Merge pull request #915 from ag2s20150909/master

Epublib优化
4 years ago · fb2d43837b
parent 41ecea7232 5b58ea45eb
commit fb2d43837b
57 changed files with 3044 additions and 3197 deletions
--- a/app/src/main/java/io/legado/app/model/localBook/EpubFile.kt
+++ b/app/src/main/java/io/legado/app/model/localBook/EpubFile.kt
@ -120,7 +120,7 @@ class EpubFile(var book: Book) {
                }
                resources.add(resource)
            } while (zipEntry != null)
-            if (resources.size() > 0) return EpubReader().readEpub(resources)
+            if (resources.size() > 0) return EpubReader().readEpubBook(resources)
        } catch (e: Exception) {
            e.printStackTrace()
        }
--- a/epublib/src/main/AndroidManifest.xml
+++ b/epublib/src/main/AndroidManifest.xml
@ -1,7 +1,4 @@
 <?xml version="1.0" encoding="utf-8"?>
-<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+<manifest package="me.ag2s.epublib">
    package="me.ag2s.epublib">
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
 </manifest>
--- a/epublib/src/main/java/me/ag2s/epublib/Constants.java
+++ b/epublib/src/main/java/me/ag2s/epublib/Constants.java
@ -6,7 +6,7 @@ public interface Constants {
  String CHARACTER_ENCODING = "UTF-8";
  String DOCTYPE_XHTML = "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD XHTML 1.1//EN\" \"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd\">";
  String NAMESPACE_XHTML = "http://www.w3.org/1999/xhtml";
-  String EPUB4J_GENERATOR_NAME = "EpubLib";
+  String EPUB_GENERATOR_NAME = "Ag2S EpubLib";
  char FRAGMENT_SEPARATOR_CHAR = '#';
  String DEFAULT_TOC_ID = "toc";
 }
--- a/epublib/src/main/java/me/ag2s/epublib/browsersupport/NavigationEvent.java
+++ b/epublib/src/main/java/me/ag2s/epublib/browsersupport/NavigationEvent.java
@ -2,7 +2,7 @@ package me.ag2s.epublib.browsersupport;
 import java.util.EventObject;
-import me.ag2s.epublib.domain.EpubBook;
+import me.ag2s.epublib.domain.Book;
 import me.ag2s.epublib.domain.Resource;
 import me.ag2s.epublib.util.StringUtil;
@ -13,6 +13,7 @@ import me.ag2s.epublib.util.StringUtil;
 * @author paul
 *
 */
@SuppressWarnings("unused")
 public class NavigationEvent extends EventObject {
  private static final long serialVersionUID = -6346750144308952762L;
@ -20,7 +21,7 @@ public class NavigationEvent extends EventObject {
  private Resource oldResource;
  private int oldSpinePos;
  private Navigator navigator;
-  private EpubBook oldBook;
+  private Book oldBook;
  private int oldSectionPos;
  private String oldFragmentId;
@ -60,7 +61,7 @@ public class NavigationEvent extends EventObject {
    this.oldFragmentId = oldFragmentId;
  }
-  public EpubBook getOldBook() {
+  public Book getOldBook() {
    return oldBook;
  }
@ -123,11 +124,11 @@ public class NavigationEvent extends EventObject {
  }
-  public void setOldBook(EpubBook oldBook) {
+  public void setOldBook(Book oldBook) {
    this.oldBook = oldBook;
  }
-  public EpubBook getCurrentBook() {
+  public Book getCurrentBook() {
    return getNavigator().getBook();
  }
@ -135,6 +136,7 @@ public class NavigationEvent extends EventObject {
    return oldResource != getCurrentResource();
  }
  @SuppressWarnings("NullableProblems")
  public String toString() {
    return StringUtil.toString(
        "oldSectionPos", oldSectionPos,
--- a/epublib/src/main/java/me/ag2s/epublib/browsersupport/NavigationEventListener.java
+++ b/epublib/src/main/java/me/ag2s/epublib/browsersupport/NavigationEventListener.java
@ -12,7 +12,7 @@ public interface NavigationEventListener {
  /**
   * Called whenever the user navigates to another position in the book.
   *
-   * @param navigationEvent
+   * @param navigationEvent f
   */
  void navigationPerformed(NavigationEvent navigationEvent);
 }
--- a/epublib/src/main/java/me/ag2s/epublib/browsersupport/NavigationHistory.java
+++ b/epublib/src/main/java/me/ag2s/epublib/browsersupport/NavigationHistory.java
@ -1,15 +1,15 @@
 package me.ag2s.epublib.browsersupport;
 import me.ag2s.epublib.domain.Book;
 import me.ag2s.epublib.domain.Resource;
 import java.util.ArrayList;
 import java.util.List;
 import me.ag2s.epublib.domain.EpubBook;
 import me.ag2s.epublib.domain.Resource;
 /**
 * A history of the user's locations with the epub.
 *
 * @author paul.siegmann
 *
 */
 public class NavigationHistory implements NavigationEventListener {
@ -36,8 +36,8 @@ public class NavigationHistory implements NavigationEventListener {
  }
  private long lastUpdateTime = 0;
-  private List<Location> locations = new ArrayList<Location>();
+  private List<Location> locations = new ArrayList<>();
-  private Navigator navigator;
+  private final Navigator navigator;
  private int currentPos = -1;
  private int currentSize = 0;
  private int maxHistorySize = DEFAULT_MAX_HISTORY_SIZE;
@ -58,11 +58,11 @@ public class NavigationHistory implements NavigationEventListener {
    return currentSize;
  }
-  public void initBook(EpubBook book) {
+  public void initBook(Book book) {
    if (book == null) {
      return;
    }
-    locations = new ArrayList<Location>();
+    locations = new ArrayList<>();
    currentPos = -1;
    currentSize = 0;
    if (navigator.getCurrentResource() != null) {
@ -103,8 +103,8 @@ public class NavigationHistory implements NavigationEventListener {
   * <br/>
   * If this nr of locations becomes larger then the historySize then the
   * first item(s) will be removed.
-   *
+   *v
-   * @param location
+   * @param location  d
   */
  public void addLocation(Location location) {
    // do nothing if the new location matches the current location
@ -149,9 +149,9 @@ public class NavigationHistory implements NavigationEventListener {
   * Moves the current positions delta positions.
   *
   * move(-1) to go one position back in history.<br/>
-   * move(1) to go one position forward.<br/>
+   * move(1) to go one position forward.<br/>发
   *
-   * @param delta
+   * @param delta f
   *
   * @return Whether we actually moved. If the requested value is illegal
   * it will return false, true otherwise.
--- a/epublib/src/main/java/me/ag2s/epublib/browsersupport/Navigator.java
+++ b/epublib/src/main/java/me/ag2s/epublib/browsersupport/Navigator.java
@ -1,12 +1,11 @@
 package me.ag2s.epublib.browsersupport;
 import me.ag2s.epublib.domain.Book;
 import me.ag2s.epublib.domain.Resource;
 import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.List;
 import me.ag2s.epublib.domain.EpubBook;
 import me.ag2s.epublib.domain.Resource;
 /**
 * A helper class for epub browser applications.
 *
@ -19,19 +18,19 @@ import me.ag2s.epublib.domain.Resource;
 public class Navigator implements Serializable {
  private static final long serialVersionUID = 1076126986424925474L;
-  private EpubBook book;
+  private Book book;
  private int currentSpinePos;
  private Resource currentResource;
  private int currentPagePos;
  private String currentFragmentId;
-  private List<NavigationEventListener> eventListeners = new ArrayList<>();
+  private final List<NavigationEventListener> eventListeners = new ArrayList<>();
  public Navigator() {
    this(null);
  }
-  public Navigator(EpubBook book) {
+  public Navigator(Book book) {
    this.book = book;
    this.currentSpinePos = 0;
    if (book != null) {
@ -136,8 +135,8 @@ public class Navigator implements Serializable {
   * Go to a specific section.
   * Illegal spine positions are silently ignored.
   *
-   * @param newSpinePos
+   * @param newSpinePos f
-   * @param source
+   * @param source f
   * @return The current position within the spine
   */
  public int gotoSpineSection(int newSpinePos, int newPagePos, Object source) {
@ -159,7 +158,7 @@ public class Navigator implements Serializable {
    return gotoSpineSection(book.getSpine().size() - 1, source);
  }
-  public void gotoBook(EpubBook book, Object source) {
+  public void gotoBook(Book book, Object source) {
    NavigationEvent navigationEvent = new NavigationEvent(source, this);
    this.book = book;
    this.currentFragmentId = null;
@ -187,14 +186,14 @@ public class Navigator implements Serializable {
   *
   * If you want the eventListeners called use gotoSection(index);
   *
-   * @param currentIndex
+   * @param currentIndex f
   */
  public void setCurrentSpinePos(int currentIndex) {
    this.currentSpinePos = currentIndex;
    this.currentResource = book.getSpine().getResource(currentIndex);
  }
-  public EpubBook getBook() {
+  public Book getBook() {
    return book;
  }
--- a/epublib/src/main/java/me/ag2s/epublib/domain/Author.java
+++ b/epublib/src/main/java/me/ag2s/epublib/domain/Author.java
@ -1,13 +1,15 @@
 package me.ag2s.epublib.domain;
 import me.ag2s.epublib.util.StringUtil;
 import java.io.Serializable;
 /**
 * Represents one of the authors of the book
 *
 * @author paul
 *
 */
 public class Author implements Serializable {
@ -42,8 +44,11 @@ public class Author implements Serializable {
        this.lastname = lastname;
    }
    @Override
    @SuppressWarnings("NullableProblems")
    public String toString() {
-    return lastname + ", " + firstname;
+        return this.lastname + ", " + this.firstname;
    }
    public int hashCode() {
@ -59,13 +64,18 @@ public class Author implements Serializable {
                && StringUtil.equals(lastname, other.lastname);
    }
-  public Relator setRole(String code) {
+    /**
     * 设置贡献者的角色
     *
     * @param code 角色编号
     */
    public void setRole(String code) {
        Relator result = Relator.byCode(code);
        if (result == null) {
            result = Relator.AUTHOR;
        }
        this.relator = result;
    return result;
    }
    public Relator getRelator() {
--- a/epublib/src/main/java/me/ag2s/epublib/domain/Book.java
+++ b/epublib/src/main/java/me/ag2s/epublib/domain/Book.java
@ -0,0 +1,323 @@
 package me.ag2s.epublib.domain;
 import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 /**
 * Representation of a Book.
 * <p>
 * All resources of a Book (html, css, xml, fonts, images) are represented
 * as Resources. See getResources() for access to these.<br/>
 * A Book as 3 indexes into these Resources, as per the epub specification.<br/>
 * <dl>
 * <dt>Spine</dt>
 * <dd>these are the Resources to be shown when a user reads the book from
 * start to finish.</dd>
 * <dt>Table of Contents<dt>
 * <dd>The table of contents. Table of Contents references may be in a
 * different order and contain different Resources than the spine, and often do.
 * <dt>Guide</dt>
 * <dd>The Guide has references to a set of special Resources like the
 * cover page, the Glossary, the copyright page, etc.
 * </dl>
 * <p/>
 * The complication is that these 3 indexes may and usually do point to
 * different pages.
 * A chapter may be split up in 2 pieces to fit it in to memory. Then the
 * spine will contain both pieces, but the Table of Contents only the first.
 * <p>
 * The Content page may be in the Table of Contents, the Guide, but not
 * in the Spine.
 * Etc.
 * <p/>
 * <p>
 * Please see the illustration at: doc/schema.svg
 *
 * @author paul
 * @author jake
 */
 public class Book implements Serializable {
    private static final long serialVersionUID = 2068355170895770100L;
    private Resources resources = new Resources();
    private Metadata metadata = new Metadata();
    private Spine spine = new Spine();
    private TableOfContents tableOfContents = new TableOfContents();
    private final Guide guide = new Guide();
    private Resource opfResource;
    private Resource ncxResource;
    private Resource coverImage;
    private String version="2.0";
    public String getVersion() {
        return version;
    }
    public void setVersion(String version) {
        this.version = version;
    }
    public boolean isEpub3() {
        return this.version.startsWith("3.");
    }
    @SuppressWarnings("UnusedReturnValue")
    public TOCReference addSection(
            TOCReference parentSection, String sectionTitle, Resource resource) {
        return addSection(parentSection, sectionTitle, resource, null);
    }
    /**
     * Adds the resource to the table of contents of the book as a child
     * section of the given parentSection
     *
     * @param parentSection parentSection
     * @param sectionTitle  sectionTitle
     * @param resource      resource
     * @param fragmentId    fragmentId
     * @return The table of contents
     */
    public TOCReference addSection(
            TOCReference parentSection, String sectionTitle, Resource resource,
            String fragmentId) {
        getResources().add(resource);
        if (spine.findFirstResourceById(resource.getId()) < 0) {
            spine.addSpineReference(new SpineReference(resource));
        }
        return parentSection.addChildSection(
                new TOCReference(sectionTitle, resource, fragmentId));
    }
    public TOCReference addSection(String title, Resource resource) {
        return addSection(title, resource, null);
    }
    /**
     * Adds a resource to the book's set of resources, table of contents and
     * if there is no resource with the id in the spine also adds it to the spine.
     *
     * @param title      title
     * @param resource   resource
     * @param fragmentId fragmentId
     * @return The table of contents
     */
    public TOCReference addSection(
            String title, Resource resource, String fragmentId) {
        getResources().add(resource);
        TOCReference tocReference = tableOfContents
                .addTOCReference(new TOCReference(title, resource, fragmentId));
        if (spine.findFirstResourceById(resource.getId()) < 0) {
            spine.addSpineReference(new SpineReference(resource));
        }
        return tocReference;
    }
    @SuppressWarnings("unused")
    public void generateSpineFromTableOfContents() {
        Spine spine = new Spine(tableOfContents);
        // in case the tocResource was already found and assigned
        spine.setTocResource(this.spine.getTocResource());
        this.spine = spine;
    }
    /**
     * The Book's metadata (titles, authors, etc)
     *
     * @return The Book's metadata (titles, authors, etc)
     */
    public Metadata getMetadata() {
        return metadata;
    }
    public void setMetadata(Metadata metadata) {
        this.metadata = metadata;
    }
    public void setResources(Resources resources) {
        this.resources = resources;
    }
    @SuppressWarnings("unused")
    public Resource addResource(Resource resource) {
        return resources.add(resource);
    }
    /**
     * The collection of all images, chapters, sections, xhtml files,
     * stylesheets, etc that make up the book.
     *
     * @return The collection of all images, chapters, sections, xhtml files,
     * stylesheets, etc that make up the book.
     */
    public Resources getResources() {
        return resources;
    }
    /**
     * The sections of the book that should be shown if a user reads the book
     * from start to finish.
     *
     * @return The Spine
     */
    public Spine getSpine() {
        return spine;
    }
    public void setSpine(Spine spine) {
        this.spine = spine;
    }
    /**
     * The Table of Contents of the book.
     *
     * @return The Table of Contents of the book.
     */
    public TableOfContents getTableOfContents() {
        return tableOfContents;
    }
    public void setTableOfContents(TableOfContents tableOfContents) {
        this.tableOfContents = tableOfContents;
    }
    /**
     * The book's cover page as a Resource.
     * An XHTML document containing a link to the cover image.
     *
     * @return The book's cover page as a Resource
     */
    public Resource getCoverPage() {
        Resource coverPage = guide.getCoverPage();
        if (coverPage == null) {
            coverPage = spine.getResource(0);
        }
        return coverPage;
    }
    public void setCoverPage(Resource coverPage) {
        if (coverPage == null) {
            return;
        }
        if (resources.notContainsByHref(coverPage.getHref())) {
            resources.add(coverPage);
        }
        guide.setCoverPage(coverPage);
    }
    /**
     * Gets the first non-blank title from the book's metadata.
     *
     * @return the first non-blank title from the book's metadata.
     */
    public String getTitle() {
        return getMetadata().getFirstTitle();
    }
    /**
     * The book's cover image.
     *
     * @return The book's cover image.
     */
    public Resource getCoverImage() {
        return coverImage;
    }
    public void setCoverImage(Resource coverImage) {
        if (coverImage == null) {
            return;
        }
        if (resources.notContainsByHref(coverImage.getHref())) {
            resources.add(coverImage);
        }
        this.coverImage = coverImage;
    }
    /**
     * The guide; contains references to special sections of the book like
     * colophon, glossary, etc.
     *
     * @return The guide; contains references to special sections of the book
     * like colophon, glossary, etc.
     */
    public Guide getGuide() {
        return guide;
    }
    /**
     * All Resources of the Book that can be reached via the Spine, the
     * TableOfContents or the Guide.
     * <p/>
     * Consists of a list of "reachable" resources:
     * <ul>
     * <li>The coverpage</li>
     * <li>The resources of the Spine that are not already in the result</li>
     * <li>The resources of the Table of Contents that are not already in the
     * result</li>
     * <li>The resources of the Guide that are not already in the result</li>
     * </ul>
     * To get all html files that make up the epub file use
     * {@link #getResources()}
     *
     * @return All Resources of the Book that can be reached via the Spine,
     * the TableOfContents or the Guide.
     */
    public List<Resource> getContents() {
        Map<String, Resource> result = new LinkedHashMap<>();
        addToContentsResult(getCoverPage(), result);
        for (SpineReference spineReference : getSpine().getSpineReferences()) {
            addToContentsResult(spineReference.getResource(), result);
        }
        for (Resource resource : getTableOfContents().getAllUniqueResources()) {
            addToContentsResult(resource, result);
        }
        for (GuideReference guideReference : getGuide().getReferences()) {
            addToContentsResult(guideReference.getResource(), result);
        }
        return new ArrayList<>(result.values());
    }
    private static void addToContentsResult(Resource resource,
                                            Map<String, Resource> allReachableResources) {
        if (resource != null && (!allReachableResources
                .containsKey(resource.getHref()))) {
            allReachableResources.put(resource.getHref(), resource);
        }
    }
    public Resource getOpfResource() {
        return opfResource;
    }
    public void setOpfResource(Resource opfResource) {
        this.opfResource = opfResource;
    }
    public void setNcxResource(Resource ncxResource) {
        this.ncxResource = ncxResource;
    }
    public Resource getNcxResource() {
        return ncxResource;
    }
 }
--- a/epublib/src/main/java/me/ag2s/epublib/domain/Date.java
+++ b/epublib/src/main/java/me/ag2s/epublib/domain/Date.java
@ -1,17 +1,17 @@
 package me.ag2s.epublib.domain;
 import me.ag2s.epublib.epub.PackageDocumentBase;
 import java.io.Serializable;
 import java.text.SimpleDateFormat;
 import java.util.Locale;
 /**
 * A Date used by the book's metadata.
- *
+ * <p>
 * Examples: creation-date, modification-date, etc
 *
 * @author paul
 *
 */
 public class Date implements Serializable {
@ -37,6 +37,8 @@ public class Date implements Serializable {
            return null;
        }
        @Override
        @SuppressWarnings("NullableProblems")
        public String toString() {
            return value;
        }
@ -65,7 +67,7 @@ public class Date implements Serializable {
    }
    public Date(java.util.Date date, String event) {
-    this((new SimpleDateFormat(PackageDocumentBase.dateFormat,Locale.US)).format(date),
+        this((new SimpleDateFormat(PackageDocumentBase.dateFormat, Locale.US)).format(date),
                event);
    }
@ -94,6 +96,8 @@ public class Date implements Serializable {
        this.event = event;
    }
    @Override
    @SuppressWarnings("NullableProblems")
    public String toString() {
        if (event == null) {
            return dateString;
--- a/epublib/src/main/java/me/ag2s/epublib/domain/EpubBook.java
+++ b/epublib/src/main/java/me/ag2s/epublib/domain/EpubBook.java
@ -1,316 +1,9 @@
 package me.ag2s.epublib.domain;
 import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 /**
- * Representation of a Book.
+ * 这个是用于其它与Book类同名时替换的
 *
 * All resources of a Book (html, css, xml, fonts, images) are represented
 * as Resources. See getResources() for access to these.<br/>
 * A Book as 3 indexes into these Resources, as per the epub specification.<br/>
 * <dl>
 * <dt>Spine</dt>
 * <dd>these are the Resources to be shown when a user reads the book from
 * start to finish.</dd>
 * <dt>Table of Contents<dt>
 * <dd>The table of contents. Table of Contents references may be in a
 * different order and contain different Resources than the spine, and often do.
 * <dt>Guide</dt>
 * <dd>The Guide has references to a set of special Resources like the
 * cover page, the Glossary, the copyright page, etc.
 * </dl>
 * <p/>
 * The complication is that these 3 indexes may and usually do point to
 * different pages.
 * A chapter may be split up in 2 pieces to fit it in to memory. Then the
 * spine will contain both pieces, but the Table of Contents only the first.
 *
 * The Content page may be in the Table of Contents, the Guide, but not
 * in the Spine.
 * Etc.
 * <p/>
 *
 * Please see the illustration at: doc/schema.svg
 *
 * @author paul
 * @author jake
 */
 public class EpubBook implements Serializable {
  private static final long serialVersionUID = 2068355170895770100L;
  private Resources resources = new Resources();
  private Metadata metadata = new Metadata();
  private Spine spine = new Spine();
  private TableOfContents tableOfContents = new TableOfContents();
  private Guide guide = new Guide();
  private Resource opfResource;
  private Resource ncxResource;
  private Resource coverImage;
  private String version;
  public String getVersion() {
    return version;
  }
  public void setVersion(String version) {
    this.version = version;
  }
  public TOCReference addSection(
      TOCReference parentSection, String sectionTitle, Resource resource) {
    return addSection(parentSection, sectionTitle, resource, null);
  }
  /**
   * Adds the resource to the table of contents of the book as a child
   * section of the given parentSection
   *
   * @param parentSection
   * @param sectionTitle
   * @param resource
   * @param fragmentId
   * @return The table of contents
   */
  public TOCReference addSection(
      TOCReference parentSection, String sectionTitle, Resource resource,
      String fragmentId) {
    getResources().add(resource);
    if (spine.findFirstResourceById(resource.getId()) < 0) {
      spine.addSpineReference(new SpineReference(resource));
    }
    return parentSection.addChildSection(
        new TOCReference(sectionTitle, resource, fragmentId));
  }
  public TOCReference addSection(String title, Resource resource) {
    return addSection(title, resource, null);
  }
  /**
   * Adds a resource to the book's set of resources, table of contents and
   * if there is no resource with the id in the spine also adds it to the spine.
   *
   * @param title
   * @param resource
   * @param fragmentId
   * @return The table of contents
   */
  public TOCReference addSection(
      String title, Resource resource, String fragmentId) {
    getResources().add(resource);
    TOCReference tocReference = tableOfContents
        .addTOCReference(new TOCReference(title, resource, fragmentId));
    if (spine.findFirstResourceById(resource.getId()) < 0) {
      spine.addSpineReference(new SpineReference(resource));
    }
    return tocReference;
  }
  public void generateSpineFromTableOfContents() {
    Spine spine = new Spine(tableOfContents);
    // in case the tocResource was already found and assigned
    spine.setTocResource(this.spine.getTocResource());
    this.spine = spine;
  }
  /**
   * The Book's metadata (titles, authors, etc)
   *
   * @return The Book's metadata (titles, authors, etc)
 */
-  public Metadata getMetadata() {
+@SuppressWarnings("unused declaration")
-    return metadata;
+public class EpubBook extends Book {
  }
  public void setMetadata(Metadata metadata) {
    this.metadata = metadata;
  }
  public void setResources(Resources resources) {
    this.resources = resources;
  }
  public Resource addResource(Resource resource) {
    return resources.add(resource);
  }
  /**
   * The collection of all images, chapters, sections, xhtml files,
   * stylesheets, etc that make up the book.
   *
   * @return The collection of all images, chapters, sections, xhtml files,
   *    stylesheets, etc that make up the book.
   */
  public Resources getResources() {
    return resources;
  }
  /**
   * The sections of the book that should be shown if a user reads the book
   * from start to finish.
   *
   * @return The Spine
   */
  public Spine getSpine() {
    return spine;
  }
  public void setSpine(Spine spine) {
    this.spine = spine;
  }
  /**
   * The Table of Contents of the book.
   *
   * @return The Table of Contents of the book.
   */
  public TableOfContents getTableOfContents() {
    return tableOfContents;
  }
  public void setTableOfContents(TableOfContents tableOfContents) {
    this.tableOfContents = tableOfContents;
  }
  /**
   * The book's cover page as a Resource.
   * An XHTML document containing a link to the cover image.
   *
   * @return The book's cover page as a Resource
   */
  public Resource getCoverPage() {
    Resource coverPage = guide.getCoverPage();
    if (coverPage == null) {
      coverPage = spine.getResource(0);
    }
    return coverPage;
  }
  public void setCoverPage(Resource coverPage) {
    if (coverPage == null) {
      return;
    }
    if (!resources.containsByHref(coverPage.getHref())) {
      resources.add(coverPage);
    }
    guide.setCoverPage(coverPage);
  }
  /**
   * Gets the first non-blank title from the book's metadata.
   *
   * @return the first non-blank title from the book's metadata.
   */
  public String getTitle() {
    return getMetadata().getFirstTitle();
  }
  /**
   * The book's cover image.
   *
   * @return The book's cover image.
   */
  public Resource getCoverImage() {
    return coverImage;
  }
  public void setCoverImage(Resource coverImage) {
    if (coverImage == null) {
      return;
    }
    if (!resources.containsByHref(coverImage.getHref())) {
      resources.add(coverImage);
    }
    this.coverImage = coverImage;
  }
  /**
   * The guide; contains references to special sections of the book like
   * colophon, glossary, etc.
   *
   * @return The guide; contains references to special sections of the book
   * like colophon, glossary, etc.
   */
  public Guide getGuide() {
    return guide;
  }
  /**
   * All Resources of the Book that can be reached via the Spine, the
   * TableOfContents or the Guide.
   * <p/>
   * Consists of a list of "reachable" resources:
   * <ul>
   * <li>The coverpage</li>
   * <li>The resources of the Spine that are not already in the result</li>
   * <li>The resources of the Table of Contents that are not already in the
   * result</li>
   * <li>The resources of the Guide that are not already in the result</li>
   * </ul>
   * To get all html files that make up the epub file use
   * {@link #getResources()}
   * @return All Resources of the Book that can be reached via the Spine,
   * the TableOfContents or the Guide.
   */
  public List<Resource> getContents() {
    Map<String, Resource> result = new LinkedHashMap<String, Resource>();
    addToContentsResult(getCoverPage(), result);
    for (SpineReference spineReference : getSpine().getSpineReferences()) {
      addToContentsResult(spineReference.getResource(), result);
    }
    for (Resource resource : getTableOfContents().getAllUniqueResources()) {
      addToContentsResult(resource, result);
    }
    for (GuideReference guideReference : getGuide().getReferences()) {
      addToContentsResult(guideReference.getResource(), result);
    }
    return new ArrayList<Resource>(result.values());
  }
  private static void addToContentsResult(Resource resource,
      Map<String, Resource> allReachableResources) {
    if (resource != null && (!allReachableResources
        .containsKey(resource.getHref()))) {
      allReachableResources.put(resource.getHref(), resource);
    }
  }
  public Resource getOpfResource() {
    return opfResource;
  }
  public void setOpfResource(Resource opfResource) {
    this.opfResource = opfResource;
  }
  public void setNcxResource(Resource ncxResource) {
    this.ncxResource = ncxResource;
  }
  public Resource getNcxResource() {
    return ncxResource;
  }
 }
--- a/epublib/src/main/java/me/ag2s/epublib/domain/Guide.java
+++ b/epublib/src/main/java/me/ag2s/epublib/domain/Guide.java
@ -25,7 +25,7 @@ public class Guide implements Serializable {
  public static final String DEFAULT_COVER_TITLE = GuideReference.COVER;
-  private List<GuideReference> references = new ArrayList<GuideReference>();
+  private List<GuideReference> references = new ArrayList<>();
  private static final int COVERPAGE_NOT_FOUND = -1;
  private static final int COVERPAGE_UNITIALIZED = -2;
@ -51,7 +51,7 @@ public class Guide implements Serializable {
    }
    return null;
  }
-
+  @SuppressWarnings("UnusedReturnValue")
  public int setCoverReference(GuideReference guideReference) {
    if (coverPageIndex >= 0) {
      references.set(coverPageIndex, guideReference);
@ -100,7 +100,7 @@ public class Guide implements Serializable {
    setCoverReference(coverpageGuideReference);
  }
-
+  @SuppressWarnings("UnusedReturnValue")
  public ResourceReference addReference(GuideReference reference) {
    this.references.add(reference);
    uncheckCoverPage();
@ -111,13 +111,13 @@ public class Guide implements Serializable {
   * A list of all GuideReferences that have the given
   * referenceTypeName (ignoring case).
   *
-   * @param referenceTypeName
+   * @param referenceTypeName referenceTypeName
   * @return A list of all GuideReferences that have the given
   *    referenceTypeName (ignoring case).
   */
  public List<GuideReference> getGuideReferencesByType(
      String referenceTypeName) {
-    List<GuideReference> result = new ArrayList<GuideReference>();
+    List<GuideReference> result = new ArrayList<>();
    for (GuideReference guideReference : references) {
      if (referenceTypeName.equalsIgnoreCase(guideReference.getType())) {
        result.add(guideReference);
--- a/epublib/src/main/java/me/ag2s/epublib/domain/GuideReference.java
+++ b/epublib/src/main/java/me/ag2s/epublib/domain/GuideReference.java
@ -20,7 +20,7 @@ public class GuideReference extends TitledResourceReference
  /**
   * the book cover(s), jacket information, etc.
   */
-  public static String COVER = "cover";
+  public static final String COVER = "cover";
  /**
   * human-readable page with title, author, publisher, and other metadata
--- a/epublib/src/main/java/me/ag2s/epublib/domain/Identifier.java
+++ b/epublib/src/main/java/me/ag2s/epublib/domain/Identifier.java
@ -15,7 +15,7 @@ import java.util.UUID;
 public class Identifier implements Serializable {
  private static final long serialVersionUID = 955949951416391810L;
-
+  @SuppressWarnings("unused")
  public interface Scheme {
    String UUID = "UUID";
@ -48,7 +48,7 @@ public class Identifier implements Serializable {
   * If no identifier has bookId == true then the first bookId identifier
   * is written as the primary.
   *
-   * @param identifiers
+   * @param identifiers i
   * @return The first identifier for which the bookId is true is made
   * 		the bookId identifier.
   */
@ -119,7 +119,8 @@ public class Identifier implements Serializable {
    return StringUtil.equals(scheme, ((Identifier) otherIdentifier).scheme)
        && StringUtil.equals(value, ((Identifier) otherIdentifier).value);
  }
-
+  @SuppressWarnings("NullableProblems")
  @Override
  public String toString() {
    if (StringUtil.isBlank(scheme)) {
      return "" + value;
--- a/epublib/src/main/java/me/ag2s/epublib/domain/LazyResource.java
+++ b/epublib/src/main/java/me/ag2s/epublib/domain/LazyResource.java
@ -3,7 +3,6 @@ package me.ag2s.epublib.domain;
 import android.util.Log;
 import me.ag2s.epublib.util.IOUtil;
 //import io.documentnode.minilog.Logger;
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.io.InputStream;
@ -15,7 +14,7 @@ import java.io.InputStream;
 public class LazyResource extends Resource {
  private static final long serialVersionUID = 5089400472352002866L;
-  private static String TAG= LazyResource.class.getName();
+  private  final String TAG= getClass().getName();
  private final LazyResourceProvider resourceProvider;
  private final long cachedSize;
@ -51,7 +50,7 @@ public class LazyResource extends Resource {
   *
   * @return The contents of the Resource.
   *
-   * @throws IOException
+   * @throws IOException IOException
   */
  public InputStream getInputStream() throws IOException {
    if (isInitialized()) {
@ -64,7 +63,7 @@ public class LazyResource extends Resource {
  /**
   * Initializes the resource by loading its data into memory.
   *
-   * @throws IOException
+   * @throws IOException IOException
   */
  public void initialize() throws IOException {
    getData();
--- a/epublib/src/main/java/me/ag2s/epublib/domain/ManifestItemProperties.java
+++ b/epublib/src/main/java/me/ag2s/epublib/domain/ManifestItemProperties.java
@ -1,5 +1,5 @@
 package me.ag2s.epublib.domain;
-
+@SuppressWarnings("unused")
 public enum ManifestItemProperties implements ManifestProperties {
  COVER_IMAGE("cover-image"),
  MATHML("mathml"),
@ -9,7 +9,7 @@ public enum ManifestItemProperties implements ManifestProperties {
  SVG("svg"),
  SWITCH("switch");
-  private String name;
+  private final String name;
  ManifestItemProperties(String name) {
    this.name = name;
--- a/epublib/src/main/java/me/ag2s/epublib/domain/ManifestItemRefProperties.java
+++ b/epublib/src/main/java/me/ag2s/epublib/domain/ManifestItemRefProperties.java
@ -1,10 +1,10 @@
 package me.ag2s.epublib.domain;
-
+@SuppressWarnings("unused")
 public enum ManifestItemRefProperties implements ManifestProperties {
 	PAGE_SPREAD_LEFT("page-spread-left"),
 	PAGE_SPREAD_RIGHT("page-spread-right");
-	private String name;
+	private final String name;
 	ManifestItemRefProperties(String name) {
 		this.name = name;
--- a/epublib/src/main/java/me/ag2s/epublib/domain/MediaType.java
+++ b/epublib/src/main/java/me/ag2s/epublib/domain/MediaType.java
@ -18,9 +18,9 @@ import java.util.Collection;
 public class MediaType implements Serializable {
  private static final long serialVersionUID = -7256091153727506788L;
-  private String name;
+  private final String name;
-  private String defaultExtension;
+  private final String defaultExtension;
-  private Collection<String> extensions;
+  private final Collection<String> extensions;
  public MediaType(String name, String defaultExtension) {
    this(name, defaultExtension, new String[]{defaultExtension});
@ -39,11 +39,11 @@ public class MediaType implements Serializable {
  }
  public MediaType(String name, String defaultExtension,
-      Collection<String> extensions) {
+      Collection<String> mextensions) {
    super();
    this.name = name;
    this.defaultExtension = defaultExtension;
-    this.extensions = extensions;
+    this.extensions = mextensions;
  }
  public String getName() {
@ -66,7 +66,7 @@ public class MediaType implements Serializable {
    }
    return name.equals(((MediaType) otherMediaType).getName());
  }
-
+  @SuppressWarnings("NullableProblems")
  public String toString() {
    return name;
  }
--- a/epublib/src/main/java/me/ag2s/epublib/domain/MediaTypes.java
+++ b/epublib/src/main/java/me/ag2s/epublib/domain/MediaTypes.java
@ -1,6 +1,5 @@
 package me.ag2s.epublib.domain;
 import me.ag2s.epublib.domain.MediaType;
 import me.ag2s.epublib.util.StringUtil;
 import java.util.HashMap;
 import java.util.Map;
@ -54,16 +53,16 @@ public class MediaTypes {
  public static final MediaType PLS = new MediaType("application/pls+xml",
      ".pls");
-  public static MediaType[] mediaTypes = new MediaType[]{
+  public static final MediaType[] mediaTypes = new MediaType[]{
      XHTML, EPUB, JPG, PNG, GIF, CSS, SVG, TTF, NCX, XPGT, OPENTYPE, WOFF,
      SMIL, PLS, JAVASCRIPT, MP3, MP4, OGG
  };
-  public static Map<String, MediaType> mediaTypesByName = new HashMap<String, MediaType>();
+  public static final Map<String, MediaType> mediaTypesByName = new HashMap<>();
  static {
-    for (int i = 0; i < mediaTypes.length; i++) {
+    for (MediaType mediaType : mediaTypes) {
-      mediaTypesByName.put(mediaTypes[i].getName(), mediaTypes[i]);
+      mediaTypesByName.put(mediaType.getName(), mediaType);
    }
  }
@ -75,7 +74,7 @@ public class MediaTypes {
   * Gets the MediaType based on the file extension.
   * Null of no matching extension found.
   *
-   * @param filename
+   * @param filename filename
   * @return the MediaType based on the file extension.
   */
  public static MediaType determineMediaType(String filename) {
--- a/epublib/src/main/java/me/ag2s/epublib/domain/Metadata.java
+++ b/epublib/src/main/java/me/ag2s/epublib/domain/Metadata.java
@ -1,11 +1,13 @@
 package me.ag2s.epublib.domain;
 import me.ag2s.epublib.util.StringUtil;
 import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import javax.xml.namespace.QName;
 /**
@ -21,27 +23,28 @@ public class Metadata implements Serializable {
    public static final String DEFAULT_LANGUAGE = "en";
-  private boolean autoGeneratedId = true;
+    private boolean autoGeneratedId;//true;
-  private List<Author> authors = new ArrayList<Author>();
+    private List<Author> authors = new ArrayList<>();
-  private List<Author> contributors = new ArrayList<Author>();
+    private List<Author> contributors = new ArrayList<>();
-  private List<Date> dates = new ArrayList<Date>();
+    private List<Date> dates = new ArrayList<>();
    private String language = DEFAULT_LANGUAGE;
-  private Map<QName, String> otherProperties = new HashMap<QName, String>();
+    private Map<QName, String> otherProperties = new HashMap<>();
-  private List<String> rights = new ArrayList<String>();
+    private List<String> rights = new ArrayList<>();
-  private List<String> titles = new ArrayList<String>();
+    private List<String> titles = new ArrayList<>();
-  private List<Identifier> identifiers = new ArrayList<Identifier>();
+    private List<Identifier> identifiers = new ArrayList<>();
-  private List<String> subjects = new ArrayList<String>();
+    private List<String> subjects = new ArrayList<>();
    private String format = MediaTypes.EPUB.getName();
-  private List<String> types = new ArrayList<String>();
+    private List<String> types = new ArrayList<>();
-  private List<String> descriptions = new ArrayList<String>();
+    private List<String> descriptions = new ArrayList<>();
-  private List<String> publishers = new ArrayList<String>();
+    private List<String> publishers = new ArrayList<>();
-  private Map<String, String> metaAttributes = new HashMap<String, String>();
+    private Map<String, String> metaAttributes = new HashMap<>();
    public Metadata() {
        identifiers.add(new Identifier());
        autoGeneratedId = true;
    }
    @SuppressWarnings("unused")
    public boolean isAutoGeneratedId() {
        return autoGeneratedId;
    }
@ -59,6 +62,7 @@ public class Metadata implements Serializable {
        this.otherProperties = otherProperties;
    }
    @SuppressWarnings("unused")
    public Date addDate(Date date) {
        this.dates.add(date);
        return date;
@ -72,6 +76,7 @@ public class Metadata implements Serializable {
        this.dates = dates;
    }
    @SuppressWarnings("UnusedReturnValue")
    public Author addAuthor(Author author) {
        authors.add(author);
        return author;
@ -85,6 +90,7 @@ public class Metadata implements Serializable {
        this.authors = authors;
    }
    @SuppressWarnings("UnusedReturnValue")
    public Author addContributor(Author contributor) {
        contributors.add(contributor);
        return contributor;
@ -154,6 +160,7 @@ public class Metadata implements Serializable {
        return titles;
    }
    @SuppressWarnings("UnusedReturnValue")
    public String addPublisher(String publisher) {
        this.publishers.add(publisher);
        return publisher;
@ -167,6 +174,7 @@ public class Metadata implements Serializable {
        return publishers;
    }
    @SuppressWarnings("UnusedReturnValue")
    public String addDescription(String description) {
        this.descriptions.add(description);
        return description;
@ -180,6 +188,7 @@ public class Metadata implements Serializable {
        return descriptions;
    }
    @SuppressWarnings("unused")
    public Identifier addIdentifier(Identifier identifier) {
        if (autoGeneratedId && (!(identifiers.isEmpty()))) {
            identifiers.set(0, identifier);
@ -207,6 +216,7 @@ public class Metadata implements Serializable {
        return format;
    }
    @SuppressWarnings("UnusedReturnValue")
    public String addType(String type) {
        this.types.add(type);
        return type;
@ -220,6 +230,7 @@ public class Metadata implements Serializable {
        this.types = types;
    }
    @SuppressWarnings("unused")
    public String getMetaAttribute(String name) {
        return metaAttributes.get(name);
    }
--- a/epublib/src/main/java/me/ag2s/epublib/domain/Resource.java
+++ b/epublib/src/main/java/me/ag2s/epublib/domain/Resource.java
@ -27,9 +27,9 @@ public class Resource implements Serializable {
  private String properties;
-  protected String originalHref;
+  protected final String originalHref;
  private MediaType mediaType;
-  private String inputEncoding = Constants.CHARACTER_ENCODING;
+  private String inputEncoding;
  protected byte[] data;
  /**
@ -147,7 +147,7 @@ public class Resource implements Serializable {
   *
   * @return The contents of the Resource.
   *
-   * @throws IOException
+   * @throws IOException IOException
   */
  public InputStream getInputStream() throws IOException {
    return new ByteArrayInputStream(getData());
@ -174,7 +174,7 @@ public class Resource implements Serializable {
   * Sets the data of the Resource.
   * If the data is a of a different type then the original data then make sure to change the MediaType.
   *
-   * @param data
+   * @param data the data of the Resource
   */
  public void setData(byte[] data) {
    this.data = data;
@ -201,7 +201,7 @@ public class Resource implements Serializable {
  /**
   * Sets the Resource's id: Make sure it is unique and a valid identifier.
   *
-   * @param id
+   * @param id Resource's id
   */
  public void setId(String id) {
    this.id = id;
@ -233,7 +233,7 @@ public class Resource implements Serializable {
  /**
   * Sets the Resource's href.
   *
-   * @param href
+   * @param href Resource's href.
   */
  public void setHref(String href) {
    this.href = href;
@ -252,7 +252,7 @@ public class Resource implements Serializable {
  /**
   * Sets the Resource's input character encoding.
   *
-   * @param encoding
+   * @param encoding Resource's input character encoding.
   */
  public void setInputEncoding(String encoding) {
    this.inputEncoding = encoding;
@ -264,7 +264,7 @@ public class Resource implements Serializable {
   * Does all sorts of smart things (courtesy of apache commons io XMLStreamREader) to handle encodings, byte order markers, etc.
   *
   * @return the contents of the Resource as Reader.
-   * @throws IOException
+   * @throws IOException IOException
   */
  public Reader getReader() throws IOException {
    return new XmlStreamReader(new ByteArrayInputStream(getData()),
@ -315,7 +315,7 @@ public class Resource implements Serializable {
  public void setProperties(String properties) {
    this.properties = properties;
  }
-
+  @SuppressWarnings("NullableProblems")
  public String toString() {
    return StringUtil.toString("id", id,
        "title", title,
--- a/epublib/src/main/java/me/ag2s/epublib/domain/ResourceReference.java
+++ b/epublib/src/main/java/me/ag2s/epublib/domain/ResourceReference.java
@ -20,7 +20,7 @@ public class ResourceReference implements Serializable {
  /**
   * Besides setting the resource it also sets the fragmentId to null.
   *
-   * @param resource
+   * @param resource resource
   */
  public void setResource(Resource resource) {
    this.resource = resource;
--- a/epublib/src/main/java/me/ag2s/epublib/domain/Resources.java
+++ b/epublib/src/main/java/me/ag2s/epublib/domain/Resources.java
@ -2,6 +2,7 @@ package me.ag2s.epublib.domain;
 import me.ag2s.epublib.Constants;
 import me.ag2s.epublib.util.StringUtil;
 import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.Arrays;
@ -15,7 +16,6 @@ import java.util.Map;
 * XHTML files, images and epub xml documents must be here.
 *
 * @author paul
 *
 */
 public class Resources implements Serializable {
@ -28,10 +28,10 @@ public class Resources implements Serializable {
    /**
     * Adds a resource to the resources.
-   *
+     * <p>
     * Fixes the resources id and href if necessary.
     *
-   * @param resource
+     * @param resource resource
     * @return the newly added resource
     */
    public Resource add(Resource resource) {
@ -44,7 +44,7 @@ public class Resources implements Serializable {
    /**
     * Checks the id of the given resource and changes to a unique identifier if it isn't one already.
     *
-   * @param resource
+     * @param resource resource
     */
    public void fixResourceId(Resource resource) {
        String resourceId = resource.getId();
@ -67,7 +67,7 @@ public class Resources implements Serializable {
    /**
     * Check if the id is a valid identifier. if not: prepend with valid identifier
     *
-   * @param resource
+     * @param resource resource
     * @return a valid id
     */
    private String makeValidId(String resourceId, Resource resource) {
@ -91,7 +91,7 @@ public class Resources implements Serializable {
    /**
     * Creates a new resource id that is guaranteed to be unique for this set of Resources
     *
-   * @param resource
+     * @param resource resource
     * @return a new resource id that is guaranteed to be unique for this set of Resources
     */
    private String createUniqueResourceId(Resource resource) {
@ -117,7 +117,7 @@ public class Resources implements Serializable {
    /**
     * Whether the map of resources already contains a resource with the given id.
     *
-   * @param id
+     * @param id id
     * @return Whether the map of resources already contains a resource with the given id.
     */
    public boolean containsId(String id) {
@ -135,7 +135,7 @@ public class Resources implements Serializable {
    /**
     * Gets the resource with the given id.
     *
-   * @param id
+     * @param id id
     * @return null if not found
     */
    public Resource getById(String id) {
@ -149,6 +149,7 @@ public class Resources implements Serializable {
        }
        return null;
    }
    public Resource getByProperties(String properties) {
        if (StringUtil.isBlank(properties)) {
            return null;
@ -164,7 +165,7 @@ public class Resources implements Serializable {
    /**
     * Remove the resource with the given href.
     *
-   * @param href
+     * @param href href
     * @return the removed resource, null if not found
     */
    public Resource remove(String href) {
@ -205,6 +206,7 @@ public class Resources implements Serializable {
    /**
     * The number of resources
     *
     * @return The number of resources
     */
    public int size() {
@ -217,6 +219,7 @@ public class Resources implements Serializable {
     *
     * @return The resources that make up this book.
     */
    @SuppressWarnings("unused")
    public Map<String, Resource> getResourceMap() {
        return resources;
    }
@ -228,21 +231,33 @@ public class Resources implements Serializable {
    /**
     * Whether there exists a resource with the given href
-   * @param href
+     *
     * @param href href
     * @return Whether there exists a resource with the given href
     */
-  public boolean containsByHref(String href) {
+    public boolean notContainsByHref(String href) {
        if (StringUtil.isBlank(href)) {
-      return false;
+            return true;
-    }
+        } else {
-    return resources.containsKey(
+            return !resources.containsKey(
                    StringUtil.substringBefore(href, Constants.FRAGMENT_SEPARATOR_CHAR));
        }
    }
    /**
     * Whether there exists a resource with the given href
     *
     * @param href href
     * @return Whether there exists a resource with the given href
     */
    @SuppressWarnings("unused")
    public boolean containsByHref(String href) {
        return !notContainsByHref(href);
    }
    /**
     * Sets the collection of Resources to the given collection of resources
     *
-   * @param resources
+     * @param resources resources
     */
    public void set(Collection<Resource> resources) {
        this.resources.clear();
@ -252,7 +267,7 @@ public class Resources implements Serializable {
    /**
     * Adds all resources from the given Collection of resources to the existing collection.
     *
-   * @param resources
+     * @param resources resources
     */
    public void addAll(Collection<Resource> resources) {
        for (Resource resource : resources) {
@ -267,7 +282,7 @@ public class Resources implements Serializable {
     * @param resources A map with as keys the resources href and as values the Resources
     */
    public void set(Map<String, Resource> resources) {
-    this.resources = new HashMap<String, Resource>(resources);
+        this.resources = new HashMap<>(resources);
    }
@ -275,7 +290,7 @@ public class Resources implements Serializable {
     * First tries to find a resource with as id the given idOrHref, if that
     * fails it tries to find one with the idOrHref as href.
     *
-   * @param idOrHref
+     * @param idOrHref idOrHref
     * @return the found Resource
     */
    public Resource getByIdOrHref(String idOrHref) {
@ -291,7 +306,7 @@ public class Resources implements Serializable {
     * Gets the resource with the given href.
     * If the given href contains a fragmentId then that fragment id will be ignored.
     *
-   * @param href
+     * @param href href
     * @return null if not found.
     */
    public Resource getByHref(String href) {
@ -299,16 +314,15 @@ public class Resources implements Serializable {
            return null;
        }
        href = StringUtil.substringBefore(href, Constants.FRAGMENT_SEPARATOR_CHAR);
-    Resource result = resources.get(href);
+        return resources.get(href);
    return result;
    }
    /**
     * Gets the first resource (random order) with the give mediatype.
-   *
+     * <p>
     * Useful for looking up the table of contents as it's supposed to be the only resource with NCX mediatype.
     *
-   * @param mediaType
+     * @param mediaType mediaType
     * @return the first resource (random order) with the give mediatype.
     */
    public Resource findFirstResourceByMediaType(MediaType mediaType) {
@ -317,10 +331,10 @@ public class Resources implements Serializable {
    /**
     * Gets the first resource (random order) with the give mediatype.
-   *
+     * <p>
     * Useful for looking up the table of contents as it's supposed to be the only resource with NCX mediatype.
     *
-   * @param mediaType
+     * @param mediaType mediaType
     * @return the first resource (random order) with the give mediatype.
     */
    public static Resource findFirstResourceByMediaType(
@ -336,11 +350,11 @@ public class Resources implements Serializable {
    /**
     * All resources that have the given MediaType.
     *
-   * @param mediaType
+     * @param mediaType mediaType
     * @return All resources that have the given MediaType.
     */
    public List<Resource> getResourcesByMediaType(MediaType mediaType) {
-    List<Resource> result = new ArrayList<Resource>();
+        List<Resource> result = new ArrayList<>();
        if (mediaType == null) {
            return result;
        }
@ -355,11 +369,12 @@ public class Resources implements Serializable {
    /**
     * All Resources that match any of the given list of MediaTypes
     *
-   * @param mediaTypes
+     * @param mediaTypes mediaType
     * @return All Resources that match any of the given list of MediaTypes
     */
    @SuppressWarnings("unused")
    public List<Resource> getResourcesByMediaTypes(MediaType[] mediaTypes) {
-    List<Resource> result = new ArrayList<Resource>();
+        List<Resource> result = new ArrayList<>();
        if (mediaTypes == null) {
            return result;
        }
--- a/epublib/src/main/java/me/ag2s/epublib/domain/Spine.java
+++ b/epublib/src/main/java/me/ag2s/epublib/domain/Spine.java
@ -22,13 +22,13 @@ public class Spine implements Serializable {
  private List<SpineReference> spineReferences;
  public Spine() {
-    this(new ArrayList<SpineReference>());
+    this(new ArrayList<>());
  }
  /**
   * Creates a spine out of all the resources in the table of contents.
   *
-   * @param tableOfContents
+   * @param tableOfContents tableOfContents
   */
  public Spine(TableOfContents tableOfContents) {
    this.spineReferences = createSpineReferences(
@ -41,7 +41,7 @@ public class Spine implements Serializable {
  public static List<SpineReference> createSpineReferences(
      Collection<Resource> resources) {
-    List<SpineReference> result = new ArrayList<SpineReference>(
+    List<SpineReference> result = new ArrayList<>(
            resources.size());
    for (Resource resource : resources) {
      result.add(new SpineReference(resource));
@ -61,7 +61,7 @@ public class Spine implements Serializable {
   * Gets the resource at the given index.
   * Null if not found.
   *
-   * @param index
+   * @param index index
   * @return the resource at the given index.
   */
  public Resource getResource(int index) {
@ -76,7 +76,7 @@ public class Spine implements Serializable {
   *
   * Null if not found.
   *
-   * @param resourceId
+   * @param resourceId resourceId
   * @return the first resource that has the given resourceId.
   */
  public int findFirstResourceById(String resourceId) {
@ -96,12 +96,12 @@ public class Spine implements Serializable {
  /**
   * Adds the given spineReference to the spine references and returns it.
   *
-   * @param spineReference
+   * @param spineReference spineReference
   * @return the given spineReference
   */
  public SpineReference addSpineReference(SpineReference spineReference) {
    if (spineReferences == null) {
-      this.spineReferences = new ArrayList<SpineReference>();
+      this.spineReferences = new ArrayList<>();
    }
    spineReferences.add(spineReference);
    return spineReference;
@ -112,6 +112,7 @@ public class Spine implements Serializable {
   *
   * @return the given spineReference
   */
  @SuppressWarnings("unused")
  public SpineReference addResource(Resource resource) {
    return addSpineReference(new SpineReference(resource));
  }
@ -130,7 +131,7 @@ public class Spine implements Serializable {
   * The epubwriter will look for it here first, followed by some clever tricks to find it elsewhere if not found.
   * Put it here to be sure of the expected behaviours.
   *
-   * @param tocResource
+   * @param tocResource tocResource
   */
  public void setTocResource(Resource tocResource) {
    this.tocResource = tocResource;
@ -149,7 +150,7 @@ public class Spine implements Serializable {
  /**
   * The position within the spine of the given resource.
   *
-   * @param currentResource
+   * @param currentResource currentResource
   * @return something &lt; 0 if not found.
   *
   */
--- a/epublib/src/main/java/me/ag2s/epublib/domain/SpineReference.java
+++ b/epublib/src/main/java/me/ag2s/epublib/domain/SpineReference.java
@ -12,7 +12,7 @@ import java.io.Serializable;
 public class SpineReference extends ResourceReference implements Serializable {
    private static final long serialVersionUID = -7921609197351510248L;
-  private boolean linear = true;
+    private boolean linear;//default = true;
    public SpineReference(Resource resource) {
        this(resource, true);
@ -28,7 +28,7 @@ public class SpineReference extends ResourceReference implements Serializable {
     * Linear denotes whether the section is Primary or Auxiliary.
     * Usually the cover page has linear set to false and all the other sections
     * have it set to true.
-   *
+     * <p>
     * It's an optional property that readers may also ignore.
     *
     * <blockquote>primary or auxiliary is useful for Reading Systems which
@ -37,9 +37,9 @@ public class SpineReference extends ResourceReference implements Serializable {
     * a popup window apart from the main window which presents the primary
     * content. (For an example of the types of content that may be considered
     * auxiliary, refer to the example below and the subsequent discussion.)</blockquote>
   * @see <a href="http://www.idpf.org/epub/20/spec/OPF_2.0.1_draft.htm#Section2.4">OPF Spine specification</a>
     *
     * @return whether the section is Primary or Auxiliary.
     * @see <a href="http://www.idpf.org/epub/20/spec/OPF_2.0.1_draft.htm#Section2.4">OPF Spine specification</a>
     */
    public boolean isLinear() {
        return linear;
--- a/epublib/src/main/java/me/ag2s/epublib/domain/TOCReference.java
+++ b/epublib/src/main/java/me/ag2s/epublib/domain/TOCReference.java
@ -17,11 +17,8 @@ public class TOCReference extends TitledResourceReference
  private static final long serialVersionUID = 5787958246077042456L;
  private List<TOCReference> children;
-  private static final Comparator<TOCReference> COMPARATOR_BY_TITLE_IGNORE_CASE =
+  private static final Comparator<TOCReference> COMPARATOR_BY_TITLE_IGNORE_CASE = (tocReference1, tocReference2) -> String.CASE_INSENSITIVE_ORDER.compare(tocReference1.getTitle(), tocReference2.getTitle());
-      (tocReference1, tocReference2) ->
+  @Deprecated
          String.CASE_INSENSITIVE_ORDER
              .compare(tocReference1.getTitle(), tocReference2.getTitle());
  public TOCReference() {
    this(null, null, null);
  }
@ -39,7 +36,7 @@ public class TOCReference extends TitledResourceReference
    super(resource, title, fragmentId);
    this.children = children;
  }
-
+  @SuppressWarnings("unused")
  public static Comparator<TOCReference> getComparatorByTitleIgnoreCase() {
    return COMPARATOR_BY_TITLE_IGNORE_CASE;
  }
--- a/epublib/src/main/java/me/ag2s/epublib/domain/TableOfContents.java
+++ b/epublib/src/main/java/me/ag2s/epublib/domain/TableOfContents.java
@ -29,7 +29,7 @@ public class TableOfContents implements Serializable {
  private List<TOCReference> tocReferences;
  public TableOfContents() {
-    this(new ArrayList<TOCReference>());
+    this(new ArrayList<>());
  }
  public TableOfContents(List<TOCReference> tocReferences) {
@ -48,6 +48,7 @@ public class TableOfContents implements Serializable {
   * Calls addTOCReferenceAtLocation after splitting the path using the DEFAULT_PATH_SEPARATOR.
   * @return the new TOCReference
   */
  @SuppressWarnings("unused")
  public TOCReference addSection(Resource resource, String path) {
    return addSection(resource, path, DEFAULT_PATH_SEPARATOR);
  }
@ -55,9 +56,9 @@ public class TableOfContents implements Serializable {
  /**
   * Calls addTOCReferenceAtLocation after splitting the path using the given pathSeparator.
   *
-   * @param resource
+   * @param resource resource
-   * @param path
+   * @param path path
-   * @param pathSeparator
+   * @param pathSeparator pathSeparator
   * @return the new TOCReference
   */
  public TOCReference addSection(Resource resource, String path,
@ -69,8 +70,8 @@ public class TableOfContents implements Serializable {
  /**
   * Finds the first TOCReference in the given list that has the same title as the given Title.
   *
-   * @param title
+   * @param title title
-   * @param tocReferences
+   * @param tocReferences tocReferences
   * @return null if not found.
   */
  private static TOCReference findTocReferenceByTitle(String title,
@ -95,8 +96,8 @@ public class TableOfContents implements Serializable {
   * will point to the given Resource</li>
   * </ul>
   *
-   * @param resource
+   * @param resource resource
-   * @param pathElements
+   * @param pathElements pathElements
   * @return the new TOCReference
   */
  public TOCReference addSection(Resource resource, String[] pathElements) {
@ -105,8 +106,7 @@ public class TableOfContents implements Serializable {
    }
    TOCReference result = null;
    List<TOCReference> currentTocReferences = this.tocReferences;
-    for (int i = 0; i < pathElements.length; i++) {
+    for (String currentTitle : pathElements) {
      String currentTitle = pathElements[i];
      result = findTocReferenceByTitle(currentTitle, currentTocReferences);
      if (result == null) {
        result = new TOCReference(currentTitle, null);
@ -130,10 +130,11 @@ public class TableOfContents implements Serializable {
   * If this TOCReference didn't exist yet it will be created and have a title of ""</li>
   * </ul>
   *
-   * @param resource
+   * @param resource resource
-   * @param pathElements
+   * @param pathElements pathElements
   * @return the new TOCReference
   */
  @SuppressWarnings("unused")
  public TOCReference addSection(Resource resource, int[] pathElements,
      String sectionTitlePrefix, String sectionNumberSeparator) {
    if (pathElements == null || pathElements.length == 0) {
--- a/epublib/src/main/java/me/ag2s/epublib/domain/TitledResourceReference.java
+++ b/epublib/src/main/java/me/ag2s/epublib/domain/TitledResourceReference.java
@ -2,6 +2,7 @@ package me.ag2s.epublib.domain;
 import me.ag2s.epublib.Constants;
 import me.ag2s.epublib.util.StringUtil;
 import java.io.Serializable;
 public class TitledResourceReference extends ResourceReference
@ -11,6 +12,13 @@ public class TitledResourceReference extends ResourceReference
    private String fragmentId;
    private String title;
    /**
     * 这会使title为null
     *
     * @param resource resource
     */
    @Deprecated
    @SuppressWarnings("unused")
    public TitledResourceReference(Resource resource) {
        this(resource, null);
    }
@ -58,8 +66,10 @@ public class TitledResourceReference extends ResourceReference
                    + fragmentId;
        }
    }
    @Override
    public Resource getResource() {
        //修复getTitle为null的bug
        resource.setTitle(title);
        return resource;
    }
--- a/epublib/src/main/java/me/ag2s/epublib/epub/BookProcessor.java
+++ b/epublib/src/main/java/me/ag2s/epublib/epub/BookProcessor.java
@ -1,6 +1,6 @@
 package me.ag2s.epublib.epub;
-import me.ag2s.epublib.domain.EpubBook;
+import me.ag2s.epublib.domain.Book;
 /**
 * Post-processes a book.
@ -16,5 +16,5 @@ public interface BookProcessor {
   */
  BookProcessor IDENTITY_BOOKPROCESSOR = book -> book;
-  EpubBook processBook(EpubBook book);
+  Book processBook(Book book);
 }
--- a/epublib/src/main/java/me/ag2s/epublib/epub/BookProcessorPipeline.java
+++ b/epublib/src/main/java/me/ag2s/epublib/epub/BookProcessorPipeline.java
@ -2,25 +2,23 @@ package me.ag2s.epublib.epub;
 import android.util.Log;
 import me.ag2s.epublib.domain.Book;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
 import me.ag2s.epublib.domain.EpubBook;
 //import io.documentnode.minilog.Logger;
 /**
 * A book processor that combines several other bookprocessors
- * <p>
+ *
 * Fixes coverpage/coverimage.
 * Cleans up the XHTML.
 *
 * @author paul.siegmann
 */
@SuppressWarnings("unused declaration")
 public class BookProcessorPipeline implements BookProcessor {
-  private static String TAG= BookProcessorPipeline.class.getName();
+  private static final String TAG= BookProcessorPipeline.class.getName();
  private List<BookProcessor> bookProcessors;
  public BookProcessorPipeline() {
@ -32,7 +30,7 @@ public class BookProcessorPipeline implements BookProcessor {
  }
  @Override
-  public EpubBook processBook(EpubBook book) {
+  public Book processBook(Book book) {
    if (bookProcessors == null) {
      return book;
    }
@ -40,7 +38,7 @@ public class BookProcessorPipeline implements BookProcessor {
      try {
        book = bookProcessor.processBook(book);
      } catch (Exception e) {
-        Log.e(TAG, e.getMessage(), e);
+        Log.e(TAG,e.getMessage(), e);
      }
    }
    return book;
@ -48,14 +46,14 @@ public class BookProcessorPipeline implements BookProcessor {
  public void addBookProcessor(BookProcessor bookProcessor) {
    if (this.bookProcessors == null) {
-      bookProcessors = new ArrayList<BookProcessor>();
+      bookProcessors = new ArrayList<>();
    }
    this.bookProcessors.add(bookProcessor);
  }
  public void addBookProcessors(Collection<BookProcessor> bookProcessors) {
    if (this.bookProcessors == null) {
-      this.bookProcessors = new ArrayList<BookProcessor>();
+      this.bookProcessors = new ArrayList<>();
    }
    this.bookProcessors.addAll(bookProcessors);
  }
--- a/epublib/src/main/java/me/ag2s/epublib/epub/DOMUtil.java
+++ b/epublib/src/main/java/me/ag2s/epublib/epub/DOMUtil.java
@ -21,10 +21,10 @@ class DOMUtil {
  /**
   * First tries to get the attribute value by doing an getAttributeNS on the element, if that gets an empty element it does a getAttribute without namespace.
   *
-   * @param element
+   * @param element element
-   * @param namespace
+   * @param namespace namespace
-   * @param attribute
+   * @param attribute attribute
-   * @return
+   * @return String Attribute
   */
  public static String getAttribute(Element element, String namespace,
      String attribute) {
@ -38,16 +38,17 @@ class DOMUtil {
  /**
   * Gets all descendant elements of the given parentElement with the given namespace and tagname and returns their text child as a list of String.
   *
-   * @param parentElement
+   * @param parentElement parentElement
-   * @param namespace
+   * @param namespace namespace
-   * @param tagname
+   * @param tagName tagName
-   * @return
+   * @return List<String>
   */
  public static List<String> getElementsTextChild(Element parentElement,
-      String namespace, String tagname) {
+      String namespace, String tagName) {
    NodeList elements = parentElement
-        .getElementsByTagNameNS(namespace, tagname);
+        .getElementsByTagNameNS(namespace, tagName);
-    List<String> result = new ArrayList<String>(elements.getLength());
+    //ArrayList 初始化时指定长度提高性能
    List<String> result = new ArrayList<>(elements.getLength());
    for (int i = 0; i < elements.getLength(); i++) {
      result.add(getTextChildrenContent((Element) elements.item(i)));
    }
@ -58,13 +59,13 @@ class DOMUtil {
   * Finds in the current document the first element with the given namespace and elementName and with the given findAttributeName and findAttributeValue.
   * It then returns the value of the given resultAttributeName.
   *
-   * @param document
+   * @param document document
-   * @param namespace
+   * @param namespace namespace
-   * @param elementName
+   * @param elementName elementName
-   * @param findAttributeName
+   * @param findAttributeName findAttributeName
-   * @param findAttributeValue
+   * @param findAttributeValue findAttributeValue
-   * @param resultAttributeName
+   * @param resultAttributeName resultAttributeName
-   * @return
+   * @return String value
   */
  public static String getFindAttributeValue(Document document,
      String namespace, String elementName, String findAttributeName,
@ -85,10 +86,10 @@ class DOMUtil {
  /**
   * Gets the first element that is a child of the parentElement and has the given namespace and tagName
   *
-   * @param parentElement
+   * @param parentElement parentElement
-   * @param namespace
+   * @param namespace namespace
-   * @param tagName
+   * @param tagName tagName
-   * @return
+   * @return Element
   */
  public static Element getFirstElementByTagNameNS(Element parentElement,
      String namespace, String tagName) {
@ -111,8 +112,8 @@ class DOMUtil {
   * when the text is Chinese characters then on Android each Characater is represented in the DOM as
   * an individual Text node.
   *
-   * @param parentElement
+   * @param parentElement parentElement
-   * @return
+   * @return String value
   */
  public static String getTextChildrenContent(Element parentElement) {
    if (parentElement == null) {
--- a/epublib/src/main/java/me/ag2s/epublib/epub/EpubProcessorSupport.java
+++ b/epublib/src/main/java/me/ag2s/epublib/epub/EpubProcessorSupport.java
@ -3,7 +3,7 @@ package me.ag2s.epublib.epub;
 import android.util.Log;
 import me.ag2s.epublib.Constants;
-//import io.documentnode.minilog.Logger;
+
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
@ -11,13 +11,14 @@ import java.io.OutputStreamWriter;
 import java.io.UnsupportedEncodingException;
 import java.io.Writer;
 import java.net.URL;
 import java.util.Objects;
 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
 import javax.xml.parsers.ParserConfigurationException;
-//import org.kxml2.io.KXmlSerializer;
+
 import org.xml.sax.EntityResolver;
 import org.xml.sax.InputSource;
 import org.xml.sax.SAXException;
 import org.xmlpull.v1.XmlPullParserFactory;
 import org.xmlpull.v1.XmlSerializer;
@ -25,11 +26,10 @@ import org.xmlpull.v1.XmlSerializer;
 * Various low-level support methods for reading/writing epubs.
 *
 * @author paul.siegmann
 *
 */
 public class EpubProcessorSupport {
-  private static String TAG= EpubProcessorSupport.class.getName();
+    private static final String TAG = EpubProcessorSupport.class.getName();
    protected static DocumentBuilderFactory documentBuilderFactory;
@ -43,7 +43,7 @@ public class EpubProcessorSupport {
        @Override
        public InputSource resolveEntity(String publicId, String systemId)
-        throws SAXException, IOException {
+                throws IOException {
            String resourcePath;
            if (systemId.startsWith("http:")) {
                URL url = new URL(systemId);
@ -55,13 +55,13 @@ public class EpubProcessorSupport {
                        previousLocation + systemId.substring(systemId.lastIndexOf('/'));
            }
-      if (this.getClass().getClassLoader().getResource(resourcePath) == null) {
+            if (Objects.requireNonNull(this.getClass().getClassLoader()).getResource(resourcePath) == null) {
                throw new RuntimeException(
                        "remote resource is not cached : [" + systemId
                                + "] cannot continue");
            }
-      InputStream in = EpubProcessorSupport.class.getClassLoader()
+            InputStream in = Objects.requireNonNull(EpubProcessorSupport.class.getClassLoader())
                    .getResourceAsStream(resourcePath);
            return new InputSource(in);
        }
@ -116,6 +116,7 @@ public class EpubProcessorSupport {
        return new EntityResolverImpl();
    }
    @SuppressWarnings("unused")
    public DocumentBuilderFactory getDocumentBuilderFactory() {
        return documentBuilderFactory;
    }
@ -131,7 +132,7 @@ public class EpubProcessorSupport {
            result = documentBuilderFactory.newDocumentBuilder();
            result.setEntityResolver(getEntityResolver());
        } catch (ParserConfigurationException e) {
-      Log.e(TAG,e.getMessage());
+            Log.e(TAG, e.getMessage());
        }
        return result;
    }
--- a/epublib/src/main/java/me/ag2s/epublib/epub/EpubReader.java
+++ b/epublib/src/main/java/me/ag2s/epublib/epub/EpubReader.java
@ -13,6 +13,7 @@ import java.util.zip.ZipFile;
 import java.util.zip.ZipInputStream;
 import me.ag2s.epublib.Constants;
 import me.ag2s.epublib.domain.Book;
 import me.ag2s.epublib.domain.EpubBook;
 import me.ag2s.epublib.domain.MediaType;
 import me.ag2s.epublib.domain.MediaTypes;
@ -21,28 +22,27 @@ import me.ag2s.epublib.domain.Resources;
 import me.ag2s.epublib.util.ResourceUtil;
 import me.ag2s.epublib.util.StringUtil;
 //import io.documentnode.minilog.Logger;
 /**
 * Reads an epub file.
 *
 * @author paul
 *
 */
 public class EpubReader {
-  private static String TAG= EpubReader.class.getName();
+    private static final String TAG = EpubReader.class.getName();
-  private BookProcessor bookProcessor = BookProcessor.IDENTITY_BOOKPROCESSOR;
+    private final BookProcessor bookProcessor = BookProcessor.IDENTITY_BOOKPROCESSOR;
-
+    @SuppressWarnings("unused")
-  public EpubBook readEpub(InputStream in) throws IOException {
+    public Book readEpub(InputStream in) throws IOException {
        return readEpub(in, Constants.CHARACTER_ENCODING);
    }
-  public EpubBook readEpub(ZipInputStream in) throws IOException {
+    @SuppressWarnings("unused")
    public Book readEpub(ZipInputStream in) throws IOException {
        return readEpub(in, Constants.CHARACTER_ENCODING);
    }
-  public EpubBook readEpub(ZipFile zipfile) throws IOException {
+    @SuppressWarnings("unused")
    public Book readEpub(ZipFile zipfile) throws IOException {
        return readEpub(zipfile, Constants.CHARACTER_ENCODING);
    }
@ -52,9 +52,9 @@ public class EpubReader {
     * @param in       the inputstream from which to read the epub
     * @param encoding the encoding to use for the html files within the epub
     * @return the Book as read from the inputstream
-   * @throws IOException
+     * @throws IOException IOException
     */
-  public EpubBook readEpub(InputStream in, String encoding) throws IOException {
+    public Book readEpub(InputStream in, String encoding) throws IOException {
        return readEpub(new ZipInputStream(in), encoding);
    }
@ -65,19 +65,20 @@ public class EpubReader {
     * @param zipFile  the file to load
     * @param encoding the encoding for XHTML files
     * @return this Book without loading all resources into memory.
-   * @throws IOException
+     * @throws IOException IOException
     */
-  public EpubBook readEpubLazy(ZipFile zipFile, String encoding)
+    @SuppressWarnings("unused")
    public Book readEpubLazy(ZipFile zipFile, String encoding)
            throws IOException {
        return readEpubLazy(zipFile, encoding,
                Arrays.asList(MediaTypes.mediaTypes));
    }
-  public EpubBook readEpub(ZipInputStream in, String encoding) throws IOException {
+    public Book readEpub(ZipInputStream in, String encoding) throws IOException {
        return readEpub(ResourcesLoader.loadResources(in, encoding));
    }
-  public EpubBook readEpub(ZipFile in, String encoding) throws IOException {
+    public Book readEpub(ZipFile in, String encoding) throws IOException {
        return readEpub(ResourcesLoader.loadResources(in, encoding));
    }
@ -88,22 +89,26 @@ public class EpubReader {
     * @param encoding        the encoding for XHTML files
     * @param lazyLoadedTypes a list of the MediaType to load lazily
     * @return this Book without loading all resources into memory.
-   * @throws IOException
+     * @throws IOException IOException
     */
-  public EpubBook readEpubLazy(ZipFile zipFile, String encoding,
+    public Book readEpubLazy(ZipFile zipFile, String encoding,
                             List<MediaType> lazyLoadedTypes) throws IOException {
        Resources resources = ResourcesLoader
                .loadResources(zipFile, encoding, lazyLoadedTypes);
        return readEpub(resources);
    }
-  public EpubBook readEpub(Resources resources) throws IOException {
+    @SuppressWarnings("unused")
-    return readEpub(resources, new EpubBook());
+    public Book readEpub(Resources resources) {
        return readEpub(resources, new Book());
    }
    public EpubBook readEpubBook(Resources resources) {
        return (EpubBook) readEpub(resources, new Book());
    }
-  public EpubBook readEpub(Resources resources, EpubBook result) throws IOException {
+    public Book readEpub(Resources resources, Book result) {
        if (result == null) {
-      result = new EpubBook();
+            result = new Book();
        }
        handleMimeType(result, resources);
        String packageResourceHref = getPackageResourceHref(resources);
@ -117,26 +122,30 @@ public class EpubReader {
    }
-  private EpubBook postProcessBook(EpubBook book) {
+    private Book postProcessBook(Book book) {
        if (bookProcessor != null) {
            book = bookProcessor.processBook(book);
        }
        return book;
    }
-  private Resource processNcxResource(Resource packageResource, EpubBook book) {
+    private Resource processNcxResource(Resource packageResource, Book book) {
        Log.d(TAG, "OPF:getHref()" + packageResource.getHref());
        if (book.isEpub3()) {
            return NCXDocumentV3.read(book, this);
        } else {
            return NCXDocumentV2.read(book, this);
        }
    return NCXDocument.read(book, this);
    }
-  private Resource processPackageResource(String packageResourceHref, EpubBook book,
+    private Resource processPackageResource(String packageResourceHref, Book book,
                                            Resources resources) {
        Resource packageResource = resources.remove(packageResourceHref);
        try {
            PackageDocumentReader.read(packageResource, this, book, resources);
        } catch (Exception e) {
-      Log.e(TAG,e.getMessage(), e);
+            Log.e(TAG, e.getMessage(), e);
        }
        return packageResource;
    }
@ -156,7 +165,7 @@ public class EpubReader {
                    .getElementsByTagName("rootfile").item(0);
            result = rootFileElement.getAttribute("full-path");
        } catch (Exception e) {
-      Log.e(TAG,e.getMessage(), e);
+            Log.e(TAG, e.getMessage(), e);
        }
        if (StringUtil.isBlank(result)) {
            result = defaultResult;
@ -164,7 +173,9 @@ public class EpubReader {
        return result;
    }
-  private void handleMimeType(EpubBook result, Resources resources) {
+    @SuppressWarnings("unused")
    private void handleMimeType(Book result, Resources resources) {
        resources.remove("mimetype");
        //result.setResources(resources);
    }
 }
--- a/epublib/src/main/java/me/ag2s/epublib/epub/EpubWriter.java
+++ b/epublib/src/main/java/me/ag2s/epublib/epub/EpubWriter.java
@ -2,8 +2,10 @@ package me.ag2s.epublib.epub;
 import android.util.Log;
-import org.xmlpull.v1.XmlSerializer;
+import me.ag2s.epublib.domain.Book;
-
+import me.ag2s.epublib.domain.MediaTypes;
 import me.ag2s.epublib.domain.Resource;
 import me.ag2s.epublib.util.IOUtil;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
@ -12,13 +14,7 @@ import java.io.Writer;
 import java.util.zip.CRC32;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipOutputStream;
-
+import org.xmlpull.v1.XmlSerializer;
 import me.ag2s.epublib.domain.EpubBook;
 import me.ag2s.epublib.domain.MediaTypes;
 import me.ag2s.epublib.domain.Resource;
 import me.ag2s.epublib.util.IOUtil;
 //import io.documentnode.minilog.Logger;
 /**
 * Generates an epub file. Not thread-safe, single use object.
@ -27,12 +23,12 @@ import me.ag2s.epublib.util.IOUtil;
 */
 public class EpubWriter {
-  private static String TAG= EpubWriter.class.getName();
+  private static final String TAG= EpubWriter.class.getName();
  // package
  static final String EMPTY_NAMESPACE_PREFIX = "";
-  private BookProcessor bookProcessor = BookProcessor.IDENTITY_BOOKPROCESSOR;
+  private BookProcessor bookProcessor;
  public EpubWriter() {
    this(BookProcessor.IDENTITY_BOOKPROCESSOR);
@ -44,7 +40,7 @@ public class EpubWriter {
  }
-  public void write(EpubBook book, OutputStream out) throws IOException {
+  public void write(Book book, OutputStream out) throws IOException {
    book = processBook(book);
    ZipOutputStream resultStream = new ZipOutputStream(out);
    writeMimeType(resultStream);
@ -55,17 +51,22 @@ public class EpubWriter {
    resultStream.close();
  }
-  private EpubBook processBook(EpubBook book) {
+  private Book processBook(Book book) {
    if (bookProcessor != null) {
      book = bookProcessor.processBook(book);
    }
    return book;
  }
-  private void initTOCResource(EpubBook book) {
+  private void initTOCResource(Book book) {
    Resource tocResource;
    try {
-      tocResource = NCXDocument.createNCXResource(book);
+      if(book.isEpub3()){
        tocResource = NCXDocumentV3.createNCXResource(book);
      }else {
        tocResource = NCXDocumentV2.createNCXResource(book);
      }
      Resource currentTocResource = book.getSpine().getTocResource();
      if (currentTocResource != null) {
        book.getResources().remove(currentTocResource.getHref());
@ -80,8 +81,7 @@ public class EpubWriter {
  }
-  private void writeResources(EpubBook book, ZipOutputStream resultStream)
+  private void writeResources(Book book, ZipOutputStream resultStream) {
          throws IOException {
    for (Resource resource : book.getResources().getAll()) {
      writeResource(resource, resultStream);
    }
@ -90,12 +90,10 @@ public class EpubWriter {
  /**
   * Writes the resource to the resultStream.
   *
-   * @param resource
+   * @param resource resource
-   * @param resultStream
+   * @param  resultStream resultStream
   * @throws IOException
   */
-  private void writeResource(Resource resource, ZipOutputStream resultStream)
+  private void writeResource(Resource resource, ZipOutputStream resultStream) {
      throws IOException {
    if (resource == null) {
      return;
    }
@ -110,7 +108,7 @@ public class EpubWriter {
  }
-  private void writePackageDocument(EpubBook book, ZipOutputStream resultStream)
+  private void writePackageDocument(Book book, ZipOutputStream resultStream)
      throws IOException {
    resultStream.putNextEntry(new ZipEntry("OEBPS/content.opf"));
    XmlSerializer xmlSerializer = EpubProcessorSupport
@ -124,8 +122,8 @@ public class EpubWriter {
  /**
   * Writes the META-INF/container.xml file.
   *
-   * @param resultStream
+   * @param  resultStream resultStream
-   * @throws IOException
+   * @throws IOException IOException
   */
  private void writeContainer(ZipOutputStream resultStream) throws IOException {
    resultStream.putNextEntry(new ZipEntry("META-INF/container.xml"));
@ -144,8 +142,8 @@ public class EpubWriter {
  /**
   * Stores the mimetype as an uncompressed file in the ZipOutputStream.
   *
-   * @param resultStream
+   * @param  resultStream resultStream
-   * @throws IOException
+   * @throws IOException IOException
   */
  private void writeMimeType(ZipOutputStream resultStream) throws IOException {
    ZipEntry mimetypeZipEntry = new ZipEntry("mimetype");
@ -175,11 +173,13 @@ public class EpubWriter {
    return MediaTypes.NCX.getName();
  }
  @SuppressWarnings("unused")
  public BookProcessor getBookProcessor() {
    return bookProcessor;
  }
-
+  @SuppressWarnings("unused")
  public void setBookProcessor(BookProcessor bookProcessor) {
    this.bookProcessor = bookProcessor;
  }
--- a/epublib/src/main/java/me/ag2s/epublib/epub/HtmlProcessor.java
+++ b/epublib/src/main/java/me/ag2s/epublib/epub/HtmlProcessor.java
@ -2,7 +2,7 @@ package me.ag2s.epublib.epub;
 import me.ag2s.epublib.domain.Resource;
 import java.io.OutputStream;
-
+@SuppressWarnings("unused")
 public interface HtmlProcessor {
  void processHtmlResource(Resource resource, OutputStream out);
--- a/epublib/src/main/java/me/ag2s/epublib/epub/Main.java
+++ b/epublib/src/main/java/me/ag2s/epublib/epub/Main.java
@ -1,5 +0,0 @@
 package me.ag2s.epublib.epub;
 public class Main {
 }
--- a/epublib/src/main/java/me/ag2s/epublib/epub/NCXDocument.java
+++ b/epublib/src/main/java/me/ag2s/epublib/epub/NCXDocument.java
@ -1,296 +0,0 @@
 package me.ag2s.epublib.epub;
 import android.util.Log;
 import org.w3c.dom.Element;
 import org.w3c.dom.NodeList;
 import org.xmlpull.v1.XmlSerializer;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.UnsupportedEncodingException;
 import java.net.URLDecoder;
 import java.util.List;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipOutputStream;
 import me.ag2s.epublib.Constants;
 import me.ag2s.epublib.domain.Author;
 import me.ag2s.epublib.domain.EpubBook;
 import me.ag2s.epublib.domain.Identifier;
 import me.ag2s.epublib.domain.MediaTypes;
 import me.ag2s.epublib.domain.Resource;
 import me.ag2s.epublib.domain.TOCReference;
 import me.ag2s.epublib.domain.TableOfContents;
 import me.ag2s.epublib.util.StringUtil;
 //import io.documentnode.minilog.Logger;
 //import javax.xml.stream.FactoryConfigurationError;
 /**
 * Writes the ncx document as defined by namespace http://www.daisy.org/z3986/2005/ncx/
 *
 * @author paul
 */
 public class NCXDocument {
    public static final String NAMESPACE_NCX = "http://www.daisy.org/z3986/2005/ncx/";
    public static final String PREFIX_NCX = "ncx";
    public static final String NCX_ITEM_ID = "ncx";
    public static final String DEFAULT_NCX_HREF = "toc.ncx";
    public static final String PREFIX_DTB = "dtb";
    private static String TAG = NCXDocument.class.getName();
    private interface NCXTags {
        String ncx = "ncx";
        String meta = "meta";
        String navPoint = "navPoint";
        String navMap = "navMap";
        String navLabel = "navLabel";
        String content = "content";
        String text = "text";
        String docTitle = "docTitle";
        String docAuthor = "docAuthor";
        String head = "head";
    }
    private interface NCXAttributes {
        String src = "src";
        String name = "name";
        String content = "content";
        String id = "id";
        String playOrder = "playOrder";
        String clazz = "class";
        String version = "version";
    }
    private interface NCXAttributeValues {
        String chapter = "chapter";
        String version = "2005-1";
    }
    public static Resource read(EpubBook book, EpubReader epubReader) {
        Log.d(TAG, book.getVersion());
        String version = book.getVersion();
        if (version.startsWith("2.")) {
            return NCXDocumentV2.read(book, epubReader);
        } else if (version.startsWith("3.")) {
            return NCXDocumentV3.read(book, epubReader);
        } else {
            return NCXDocumentV2.read(book, epubReader);
        }
    }
    private static List<TOCReference> readTOCReferences(NodeList navpoints,
                                                        EpubBook book) {
        Log.d(TAG, book.getVersion());
        String version = book.getVersion();
        if (version.startsWith("2.")) {
            return NCXDocumentV2.readTOCReferences(navpoints, book);
        } else if (version.startsWith("3.")) {
            return NCXDocumentV3.readTOCReferences(navpoints, book);
        } else {
            return NCXDocumentV2.readTOCReferences(navpoints, book);
        }
    }
    static TOCReference readTOCReference(Element navpointElement, EpubBook book) {
        Log.d(TAG, book.getVersion());
        String version = book.getVersion();
        if (version.startsWith("2.")) {
            return NCXDocumentV2.readTOCReference(navpointElement, book);
        } else if (version.startsWith("3.")) {
            return NCXDocumentV3.readTOCReference(navpointElement, book);
        } else {
            return NCXDocumentV2.readTOCReference(navpointElement, book);
        }
    }
    private static String readNavReference(Element navpointElement) {
        Element contentElement = DOMUtil
                .getFirstElementByTagNameNS(navpointElement, NAMESPACE_NCX,
                        NCXTags.content);
        String result = DOMUtil
                .getAttribute(contentElement, NAMESPACE_NCX, NCXAttributes.src);
        try {
            result = URLDecoder.decode(result, Constants.CHARACTER_ENCODING);
        } catch (UnsupportedEncodingException e) {
            Log.e(TAG, e.getMessage());
        }
        return result;
    }
    private static String readNavLabel(Element navpointElement) {
        Element navLabel = DOMUtil
                .getFirstElementByTagNameNS(navpointElement, NAMESPACE_NCX,
                        NCXTags.navLabel);
        return DOMUtil.getTextChildrenContent(DOMUtil
                .getFirstElementByTagNameNS(navLabel, NAMESPACE_NCX, NCXTags.text));
    }
    public static void write(EpubWriter epubWriter, EpubBook book,
                             ZipOutputStream resultStream) throws IOException {
        resultStream
                .putNextEntry(new ZipEntry(book.getSpine().getTocResource().getHref()));
        XmlSerializer out = EpubProcessorSupport.createXmlSerializer(resultStream);
        write(out, book);
        out.flush();
    }
    /**
     * Generates a resource containing an xml document containing the table of contents of the book in ncx format.
     *
     * @param xmlSerializer the serializer used
     * @param book          the book to serialize
     * @throws IOException
     * @throws IllegalStateException
     * @throws IllegalArgumentException
     * @1throws FactoryConfigurationError
     */
    public static void write(XmlSerializer xmlSerializer, EpubBook book)
            throws IllegalArgumentException, IllegalStateException, IOException {
        write(xmlSerializer, book.getMetadata().getIdentifiers(), book.getTitle(),
                book.getMetadata().getAuthors(), book.getTableOfContents());
    }
    public static Resource createNCXResource(EpubBook book)
            throws IllegalArgumentException, IllegalStateException, IOException {
        return createNCXResource(book.getMetadata().getIdentifiers(),
                book.getTitle(), book.getMetadata().getAuthors(),
                book.getTableOfContents());
    }
    public static Resource createNCXResource(List<Identifier> identifiers,
                                             String title, List<Author> authors, TableOfContents tableOfContents)
            throws IllegalArgumentException, IllegalStateException, IOException {
        ByteArrayOutputStream data = new ByteArrayOutputStream();
        XmlSerializer out = EpubProcessorSupport.createXmlSerializer(data);
        write(out, identifiers, title, authors, tableOfContents);
        Resource resource = new Resource(NCX_ITEM_ID, data.toByteArray(),
                DEFAULT_NCX_HREF, MediaTypes.NCX);
        return resource;
    }
    public static void write(XmlSerializer serializer,
                             List<Identifier> identifiers, String title, List<Author> authors,
                             TableOfContents tableOfContents)
            throws IllegalArgumentException, IllegalStateException, IOException {
        serializer.startDocument(Constants.CHARACTER_ENCODING, false);
        serializer.setPrefix(EpubWriter.EMPTY_NAMESPACE_PREFIX, NAMESPACE_NCX);
        serializer.startTag(NAMESPACE_NCX, NCXTags.ncx);
 //		serializer.writeNamespace("ncx", NAMESPACE_NCX);
 //		serializer.attribute("xmlns", NAMESPACE_NCX);
        serializer
                .attribute(EpubWriter.EMPTY_NAMESPACE_PREFIX, NCXAttributes.version,
                        NCXAttributeValues.version);
        serializer.startTag(NAMESPACE_NCX, NCXTags.head);
        for (Identifier identifier : identifiers) {
            writeMetaElement(identifier.getScheme(), identifier.getValue(),
                    serializer);
        }
        writeMetaElement("generator", Constants.EPUB4J_GENERATOR_NAME, serializer);
        writeMetaElement("depth", String.valueOf(tableOfContents.calculateDepth()),
                serializer);
        writeMetaElement("totalPageCount", "0", serializer);
        writeMetaElement("maxPageNumber", "0", serializer);
        serializer.endTag(NAMESPACE_NCX, "head");
        serializer.startTag(NAMESPACE_NCX, NCXTags.docTitle);
        serializer.startTag(NAMESPACE_NCX, NCXTags.text);
        // write the first title
        serializer.text(StringUtil.defaultIfNull(title));
        serializer.endTag(NAMESPACE_NCX, NCXTags.text);
        serializer.endTag(NAMESPACE_NCX, NCXTags.docTitle);
        for (Author author : authors) {
            serializer.startTag(NAMESPACE_NCX, NCXTags.docAuthor);
            serializer.startTag(NAMESPACE_NCX, NCXTags.text);
            serializer.text(author.getLastname() + ", " + author.getFirstname());
            serializer.endTag(NAMESPACE_NCX, NCXTags.text);
            serializer.endTag(NAMESPACE_NCX, NCXTags.docAuthor);
        }
        serializer.startTag(NAMESPACE_NCX, NCXTags.navMap);
        writeNavPoints(tableOfContents.getTocReferences(), 1, serializer);
        serializer.endTag(NAMESPACE_NCX, NCXTags.navMap);
        serializer.endTag(NAMESPACE_NCX, "ncx");
        serializer.endDocument();
    }
    private static void writeMetaElement(String dtbName, String content,
                                         XmlSerializer serializer)
            throws IllegalArgumentException, IllegalStateException, IOException {
        serializer.startTag(NAMESPACE_NCX, NCXTags.meta);
        serializer.attribute(EpubWriter.EMPTY_NAMESPACE_PREFIX, NCXAttributes.name,
                PREFIX_DTB + ":" + dtbName);
        serializer
                .attribute(EpubWriter.EMPTY_NAMESPACE_PREFIX, NCXAttributes.content,
                        content);
        serializer.endTag(NAMESPACE_NCX, NCXTags.meta);
    }
    private static int writeNavPoints(List<TOCReference> tocReferences,
                                      int playOrder,
                                      XmlSerializer serializer)
            throws IllegalArgumentException, IllegalStateException, IOException {
        for (TOCReference tocReference : tocReferences) {
            if (tocReference.getResource() == null) {
                playOrder = writeNavPoints(tocReference.getChildren(), playOrder,
                        serializer);
                continue;
            }
            writeNavPointStart(tocReference, playOrder, serializer);
            playOrder++;
            if (!tocReference.getChildren().isEmpty()) {
                playOrder = writeNavPoints(tocReference.getChildren(), playOrder,
                        serializer);
            }
            writeNavPointEnd(tocReference, serializer);
        }
        return playOrder;
    }
    private static void writeNavPointStart(TOCReference tocReference,
                                           int playOrder, XmlSerializer serializer)
            throws IllegalArgumentException, IllegalStateException, IOException {
        serializer.startTag(NAMESPACE_NCX, NCXTags.navPoint);
        serializer.attribute(EpubWriter.EMPTY_NAMESPACE_PREFIX, NCXAttributes.id,
                "navPoint-" + playOrder);
        serializer
                .attribute(EpubWriter.EMPTY_NAMESPACE_PREFIX, NCXAttributes.playOrder,
                        String.valueOf(playOrder));
        serializer.attribute(EpubWriter.EMPTY_NAMESPACE_PREFIX, NCXAttributes.clazz,
                NCXAttributeValues.chapter);
        serializer.startTag(NAMESPACE_NCX, NCXTags.navLabel);
        serializer.startTag(NAMESPACE_NCX, NCXTags.text);
        serializer.text(tocReference.getTitle());
        serializer.endTag(NAMESPACE_NCX, NCXTags.text);
        serializer.endTag(NAMESPACE_NCX, NCXTags.navLabel);
        serializer.startTag(NAMESPACE_NCX, NCXTags.content);
        serializer.attribute(EpubWriter.EMPTY_NAMESPACE_PREFIX, NCXAttributes.src,
                tocReference.getCompleteHref());
        serializer.endTag(NAMESPACE_NCX, NCXTags.content);
    }
    private static void writeNavPointEnd(TOCReference tocReference,
                                         XmlSerializer serializer)
            throws IllegalArgumentException, IllegalStateException, IOException {
        serializer.endTag(NAMESPACE_NCX, NCXTags.navPoint);
    }
 }
--- a/epublib/src/main/java/me/ag2s/epublib/epub/NCXDocumentV2.java
+++ b/epublib/src/main/java/me/ag2s/epublib/epub/NCXDocumentV2.java
@ -19,7 +19,7 @@ import java.util.zip.ZipOutputStream;
 import me.ag2s.epublib.Constants;
 import me.ag2s.epublib.domain.Author;
-import me.ag2s.epublib.domain.EpubBook;
+import me.ag2s.epublib.domain.Book;
 import me.ag2s.epublib.domain.Identifier;
 import me.ag2s.epublib.domain.MediaTypes;
 import me.ag2s.epublib.domain.Resource;
@ -33,15 +33,16 @@ import me.ag2s.epublib.util.StringUtil;
 *
 * @author paul
 */
-public class NCXDocumentV2 extends NCXDocument{
+public class NCXDocumentV2 {
    public static final String NAMESPACE_NCX = "http://www.daisy.org/z3986/2005/ncx/";
    @SuppressWarnings("unused")
    public static final String PREFIX_NCX = "ncx";
    public static final String NCX_ITEM_ID = "ncx";
    public static final String DEFAULT_NCX_HREF = "toc.ncx";
    public static final String PREFIX_DTB = "dtb";
-  private static String TAG= NCXDocumentV2.class.getName();
+    private static final String TAG = NCXDocumentV2.class.getName();
    private interface NCXTags {
@ -75,34 +76,38 @@ public class NCXDocumentV2 extends NCXDocument{
    }
-  public static Resource read(EpubBook book, EpubReader epubReader) {
+    @SuppressWarnings("unused")
    public static Resource read(Book book, EpubReader epubReader) {
        Resource ncxResource = null;
        if (book.getSpine().getTocResource() == null) {
            Log.e(TAG, "Book does not contain a table of contents file");
-      return ncxResource;
+            return null;
        }
        try {
            ncxResource = book.getSpine().getTocResource();
            if (ncxResource == null) {
-        return ncxResource;
+                return null;
            }
-      Log.d(TAG,ncxResource.getHref());
+            Log.d(TAG, ncxResource.getHref());
            Document ncxDocument = ResourceUtil.getAsDocument(ncxResource);
            Element navMapElement = DOMUtil
                    .getFirstElementByTagNameNS(ncxDocument.getDocumentElement(),
                            NAMESPACE_NCX, NCXTags.navMap);
            if (navMapElement == null) {
                return null;
            }
            TableOfContents tableOfContents = new TableOfContents(
                    readTOCReferences(navMapElement.getChildNodes(), book));
            book.setTableOfContents(tableOfContents);
        } catch (Exception e) {
-      Log.e(TAG,e.getMessage(), e);
+            Log.e(TAG, e.getMessage(), e);
        }
        return ncxResource;
    }
    static List<TOCReference> readTOCReferences(NodeList navpoints,
-                                              EpubBook book) {
+                                                Book book) {
        if (navpoints == null) {
            return new ArrayList<>();
        }
@ -122,7 +127,7 @@ public class NCXDocumentV2 extends NCXDocument{
        return result;
    }
-  static TOCReference readTOCReference(Element navpointElement, EpubBook book) {
+    static TOCReference readTOCReference(Element navpointElement, Book book) {
        String label = readNavLabel(navpointElement);
        //Log.d(TAG,"label:"+label);
        String tocResourceRoot = StringUtil
@ -141,8 +146,11 @@ public class NCXDocumentV2 extends NCXDocument{
                .substringAfter(reference, Constants.FRAGMENT_SEPARATOR_CHAR);
        Resource resource = book.getResources().getByHref(href);
        if (resource == null) {
-      Log.e(TAG,"Resource with href " + href + " in NCX document not found");
+            Log.e(TAG, "Resource with href " + href + " in NCX document not found");
        }
        Log.d(TAG, "label:" + label);
        Log.d(TAG, "href:" + href);
        Log.d(TAG, "fragmentId:" + fragmentId);
        TOCReference result = new TOCReference(label, resource, fragmentId);
        List<TOCReference> childTOCReferences = readTOCReferences(
                navpointElement.getChildNodes(), book);
@ -154,12 +162,15 @@ public class NCXDocumentV2 extends NCXDocument{
        Element contentElement = DOMUtil
                .getFirstElementByTagNameNS(navpointElement, NAMESPACE_NCX,
                        NCXTags.content);
        if (contentElement == null) {
            return null;
        }
        String result = DOMUtil
                .getAttribute(contentElement, NAMESPACE_NCX, NCXAttributes.src);
        try {
            result = URLDecoder.decode(result, Constants.CHARACTER_ENCODING);
        } catch (UnsupportedEncodingException e) {
-      Log.e(TAG,e.getMessage());
+            Log.e(TAG, e.getMessage());
        }
        return result;
    }
@ -169,12 +180,12 @@ public class NCXDocumentV2 extends NCXDocument{
        Element navLabel = DOMUtil
                .getFirstElementByTagNameNS(navpointElement, NAMESPACE_NCX,
                        NCXTags.navLabel);
        assert navLabel != null;
        return DOMUtil.getTextChildrenContent(DOMUtil
                .getFirstElementByTagNameNS(navLabel, NAMESPACE_NCX, NCXTags.text));
    }
-
+    @SuppressWarnings("unused")
-
+    public static void write(EpubWriter epubWriter, Book book,
  public static void write(EpubWriter epubWriter, EpubBook book,
                             ZipOutputStream resultStream) throws IOException {
        resultStream
                .putNextEntry(new ZipEntry(book.getSpine().getTocResource().getHref()));
@ -189,19 +200,17 @@ public class NCXDocumentV2 extends NCXDocument{
     *
     * @param xmlSerializer the serializer used
     * @param book          the book to serialize
-   *
+     * @throws IOException IOException
-   * @1throws FactoryConfigurationError
+     * @throws  IllegalStateException IllegalStateException
-   * @throws IOException
+     * @throws IllegalArgumentException IllegalArgumentException
   * @throws IllegalStateException
   * @throws IllegalArgumentException
     */
-  public static void write(XmlSerializer xmlSerializer, EpubBook book)
+    public static void write(XmlSerializer xmlSerializer, Book book)
            throws IllegalArgumentException, IllegalStateException, IOException {
        write(xmlSerializer, book.getMetadata().getIdentifiers(), book.getTitle(),
                book.getMetadata().getAuthors(), book.getTableOfContents());
    }
-  public static Resource createNCXResource(EpubBook book)
+    public static Resource createNCXResource(Book book)
            throws IllegalArgumentException, IllegalStateException, IOException {
        return createNCXResource(book.getMetadata().getIdentifiers(),
                book.getTitle(), book.getMetadata().getAuthors(),
@ -214,9 +223,8 @@ public class NCXDocumentV2 extends NCXDocument{
        ByteArrayOutputStream data = new ByteArrayOutputStream();
        XmlSerializer out = EpubProcessorSupport.createXmlSerializer(data);
        write(out, identifiers, title, authors, tableOfContents);
-    Resource resource = new Resource(NCX_ITEM_ID, data.toByteArray(),
+        return new Resource(NCX_ITEM_ID, data.toByteArray(),
                DEFAULT_NCX_HREF, MediaTypes.NCX);
    return resource;
    }
    public static void write(XmlSerializer serializer,
@ -238,7 +246,7 @@ public class NCXDocumentV2 extends NCXDocument{
                    serializer);
        }
-    writeMetaElement("generator", Constants.EPUB4J_GENERATOR_NAME, serializer);
+        writeMetaElement("generator", Constants.EPUB_GENERATOR_NAME, serializer);
        writeMetaElement("depth", String.valueOf(tableOfContents.calculateDepth()),
                serializer);
        writeMetaElement("totalPageCount", "0", serializer);
@ -325,7 +333,7 @@ public class NCXDocumentV2 extends NCXDocument{
                tocReference.getCompleteHref());
        serializer.endTag(NAMESPACE_NCX, NCXTags.content);
    }
-
+    @SuppressWarnings("unused")
    private static void writeNavPointEnd(TOCReference tocReference,
                                         XmlSerializer serializer)
            throws IllegalArgumentException, IllegalStateException, IOException {
--- a/epublib/src/main/java/me/ag2s/epublib/epub/NCXDocumentV3.java
+++ b/epublib/src/main/java/me/ag2s/epublib/epub/NCXDocumentV3.java
@ -6,79 +6,114 @@ import org.w3c.dom.Document;
 import org.w3c.dom.Element;
 import org.w3c.dom.Node;
 import org.w3c.dom.NodeList;
 import org.xmlpull.v1.XmlSerializer;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.UnsupportedEncodingException;
 import java.net.URLDecoder;
 import java.util.ArrayList;
 import java.util.List;
 import me.ag2s.epublib.Constants;
-import me.ag2s.epublib.domain.EpubBook;
+import me.ag2s.epublib.domain.Author;
 import me.ag2s.epublib.domain.Book;
 import me.ag2s.epublib.domain.Identifier;
 import me.ag2s.epublib.domain.MediaType;
 import me.ag2s.epublib.domain.MediaTypes;
 import me.ag2s.epublib.domain.Resource;
 import me.ag2s.epublib.domain.TOCReference;
 import me.ag2s.epublib.domain.TableOfContents;
 import me.ag2s.epublib.util.ResourceUtil;
 import me.ag2s.epublib.util.StringUtil;
-public class NCXDocumentV3 extends NCXDocument {
+/**
-    public static final String NAMESPACE_NCX = "";
+ * Writes the ncx document as defined by namespace http://www.daisy.org/z3986/2005/ncx/
-    public static final String PREFIX_NCX = "html";
+ *
-    public static final String NCX_ITEM_ID = "ncx";
+ * @author Ag2S20150909
 */
 public class NCXDocumentV3 {
    public static final String NAMESPACE_XHTML = "http://www.w3.org/1999/xhtml";
    public static final String NAMESPACE_EPUB = "http://www.idpf.org/2007/ops";
    public static final String LANGUAGE = "en";
    @SuppressWarnings("unused")
    public static final String PREFIX_XHTML = "html";
    public static final String NCX_ITEM_ID = "htmltoc";
    public static final String DEFAULT_NCX_HREF = "toc.xhtml";
-    public static final String PREFIX_DTB = "dtb";
+    public static final String V3_NCX_PROPERTIES = "nav";
-    private static String TAG = NCXDocumentV3.class.getName();
+    public static final MediaType V3_NCX_MEDIATYPE = MediaTypes.XHTML;
-    private interface NCXTags {
+    private static final String TAG = NCXDocumentV3.class.getName();
-        //String nav="nav";
+
-        //String li="li";
+    private interface XHTMLTgs {
-        //String ncx = "ncx";
+        String html = "html";
        String meta = "meta";
        String navPoint = "li";
        String navMap = "nav";
        String navLabel = "a";
        String content = "a";
        String text = "text";
        String docTitle = "docTitle";
        String docAuthor = "docAuthor";
        String head = "head";
        String title = "title";
        String meta = "meta";
        String link = "link";
        String body = "body";
        String h1 = "h1";
        String h2 = "h2";
        String nav = "nav";
        String ol = "ol";
        String li = "li";
        String a = "a";
        String span = "span";
    }
-    private interface NCXAttributes {
+    private interface XHTMLAttributes {
-
+        String xmlns = "xmlns";
-        String src = "href";
+        String xmlns_epub = "xmlns:epub";
-        String name = "name";
+        String lang = "lang";
-        String content = "content";
+        String xml_lang = "xml:lang";
        String rel = "rel";
        String type = "type";
        String epub_type = "epub:type";//nav的必须属性
        String id = "id";
-        String playOrder = "playOrder";
+        String role = "role";
-        String clazz = "class";
+        String href = "href";
-        String version = "version";
+        String http_equiv = "http-equiv";
-    }
+        String content = "content";
-    private interface NCXAttributeValues {
+    }
-        String chapter = "chapter";
+    private interface XHTMLAttributeValues {
-        String version = "2007";
+        String Content_Type = "Content-Type";
        String HTML_UTF8 = "text/html; charset=utf-8";
        String lang = "en";
        String epub_type = "toc";
        String role_toc = "doc-toc";
    }
-    public static Resource read(EpubBook book, EpubReader epubReader) {
+
    /**
     * 解析epub的目录文件
     *
     * @param book       Book
     * @param epubReader epubreader
     * @return Resource
     */
    @SuppressWarnings("unused")
    public static Resource read(Book book, EpubReader epubReader) {
        Resource ncxResource = null;
        if (book.getSpine().getTocResource() == null) {
            Log.e(TAG, "Book does not contain a table of contents file");
-            return ncxResource;
+            return null;
        }
        try {
            ncxResource = book.getSpine().getTocResource();
            if (ncxResource == null) {
-                return ncxResource;
+                return null;
            }
            //Log.d(TAG, ncxResource.getHref());
            Document ncxDocument = ResourceUtil.getAsDocument(ncxResource);
            //Log.d(TAG, ncxDocument.getNodeName());
-            Element navMapElement = (Element) ncxDocument.getElementsByTagName("nav").item(0);
+            Element navMapElement = (Element) ncxDocument.getElementsByTagName(XHTMLTgs.nav).item(0);
-            navMapElement = (Element) navMapElement.getElementsByTagName("ol").item(0);
+            navMapElement = (Element) navMapElement.getElementsByTagName(XHTMLTgs.ol).item(0);
            Log.d(TAG, navMapElement.getTagName());
            TableOfContents tableOfContents = new TableOfContents(
@ -91,46 +126,42 @@ public class NCXDocumentV3 extends NCXDocument {
        return ncxResource;
    }
-    public static List<TOCReference> doToc(Node n, EpubBook book) {
+    private static List<TOCReference> doToc(Node n, Book book) {
        List<TOCReference> result = new ArrayList<>();
        if (n == null || n.getNodeType() != Document.ELEMENT_NODE) {
            return result;
        } else {
            Element el = (Element) n;
-            NodeList nodeList = el.getElementsByTagName("li");
+            NodeList nodeList = el.getElementsByTagName(XHTMLTgs.li);
            for (int i = 0; i < nodeList.getLength(); i++) {
                result.add(readTOCReference((Element) nodeList.item(i), book));
            }
        }
        return result;
    }
    static List<TOCReference> readTOCReferences(NodeList navpoints,
-                                                EpubBook book) {
+                                                Book book) {
        if (navpoints == null) {
            return new ArrayList<>();
        }
        //Log.d(TAG, "readTOCReferences:navpoints.getLength()" + navpoints.getLength());
-        List<TOCReference> result = new ArrayList<>();
+        List<TOCReference> result = new ArrayList<>(navpoints.getLength());
        for (int i = 0; i < navpoints.getLength(); i++) {
            Node node = navpoints.item(i);
            //如果该node是null,或者不是Element,跳出本次循环
            if (node == null || node.getNodeType() != Document.ELEMENT_NODE) {
                continue;
-            } else {
+            }
            Element el = (Element) node;
-                if (el.getTagName().equals("li")) {
+            //如果该Element的name为”li“,将其添加到目录结果
            if (el.getTagName().equals(XHTMLTgs.li)) {
                result.add(readTOCReference(el, book));
            }
-                //NodeList nodeList=el.getElementsByTagName("li");
+
                //for (int i=0;i<nodeList.getLength();i++){
                //result.add(readTOCReference((Element) nodeList.item(i),book));
                // }
            }
            //result.addAll(doToc(node, book));
        }
@ -138,7 +169,8 @@ public class NCXDocumentV3 extends NCXDocument {
    }
-    static TOCReference readTOCReference(Element navpointElement, EpubBook book) {
+    static TOCReference readTOCReference(Element navpointElement, Book book) {
        //章节的名称
        String label = readNavLabel(navpointElement);
        //Log.d(TAG, "label:" + label);
        String tocResourceRoot = StringUtil
@ -160,7 +192,13 @@ public class NCXDocumentV3 extends NCXDocument {
        if (resource == null) {
            Log.e(TAG, "Resource with href " + href + " in NCX document not found");
        }
        Log.v(TAG, "label:" + label);
        Log.v(TAG, "href:" + href);
        Log.v(TAG, "fragmentId:" + fragmentId);
        //父级目录
        TOCReference result = new TOCReference(label, resource, fragmentId);
        //解析子级目录
        List<TOCReference> childTOCReferences = doToc(navpointElement, book);
        //readTOCReferences(
        //navpointElement.getChildNodes(), book);
@ -168,13 +206,24 @@ public class NCXDocumentV3 extends NCXDocument {
        return result;
    }
    /**
     * 获取目录节点的href
     *
     * @param navpointElement navpointElement
     * @return String
     */
    private static String readNavReference(Element navpointElement) {
        //https://www.w3.org/publishing/epub/epub-packages.html#sec-package-nav
        //父级节点必须是 "li"
        //Log.d(TAG, "readNavReference:" + navpointElement.getTagName());
        Element contentElement = DOMUtil
-                .getFirstElementByTagNameNS(navpointElement, NAMESPACE_NCX,
+                .getFirstElementByTagNameNS(navpointElement, "", XHTMLTgs.a);
-                        NCXDocumentV3.NCXTags.content);
+        if (contentElement == null) {
            return null;
        }
        String result = DOMUtil
-                .getAttribute(contentElement, NAMESPACE_NCX, NCXDocumentV3.NCXAttributes.src);
+                .getAttribute(contentElement, "", XHTMLAttributes.href);
        try {
            result = URLDecoder.decode(result, Constants.CHARACTER_ENCODING);
        } catch (UnsupportedEncodingException e) {
@ -185,13 +234,218 @@ public class NCXDocumentV3 extends NCXDocument {
    }
    /**
     * 获取目录节点里面的章节名
     *
     * @param navpointElement navpointElement
     * @return String
     */
    private static String readNavLabel(Element navpointElement) {
        //https://www.w3.org/publishing/epub/epub-packages.html#sec-package-nav
        //父级节点必须是 "li"
        //Log.d(TAG, "readNavLabel:" + navpointElement.getTagName());
-        Element navLabel = DOMUtil
+        String label;
-                .getFirstElementByTagNameNS(navpointElement, NAMESPACE_NCX,
+        Element labelElement = DOMUtil.getFirstElementByTagNameNS(navpointElement, "", "a");
-                        NCXDocumentV3.NCXTags.navLabel);
+        assert labelElement != null;
-        return navLabel.getTextContent();//DOMUtil.getTextChildrenContent(DOMUtil
+        label = labelElement.getTextContent();
-        //.getFirstElementByTagNameNS(navLabel, NAMESPACE_NCX, NCXDocumentV3.NCXTags.text));
+        if (StringUtil.isNotBlank(label)) {
            return label;
        } else {
            labelElement = DOMUtil.getFirstElementByTagNameNS(navpointElement, "", "span");
        }
        assert labelElement != null;
        label = labelElement.getTextContent();
        //如果通过 a 标签无法获取章节列表,则是无href章节名
        return label;
    }
    public static Resource createNCXResource(Book book)
            throws IllegalArgumentException, IllegalStateException, IOException {
        return createNCXResource(book.getMetadata().getIdentifiers(),
                book.getTitle(), book.getMetadata().getAuthors(),
                book.getTableOfContents());
    }
    public static Resource createNCXResource(List<Identifier> identifiers,
                                             String title, List<Author> authors, TableOfContents tableOfContents)
            throws IllegalArgumentException, IllegalStateException, IOException {
        ByteArrayOutputStream data = new ByteArrayOutputStream();
        XmlSerializer out = EpubProcessorSupport.createXmlSerializer(data);
        write(out, identifiers, title, authors, tableOfContents);
        Resource resource = new Resource(NCX_ITEM_ID, data.toByteArray(),
                DEFAULT_NCX_HREF, V3_NCX_MEDIATYPE);
        resource.setProperties(V3_NCX_PROPERTIES);
        return resource;
    }
    /**
     * Generates a resource containing an xml document containing the table of contents of the book in ncx format.
     *
     * @param xmlSerializer the serializer used
     * @param book          the book to serialize
     * @throws IOException              IOException
     * @throws IllegalStateException    IllegalStateException
     * @throws IllegalArgumentException IllegalArgumentException
     */
    public static void write(XmlSerializer xmlSerializer, Book book)
            throws IllegalArgumentException, IllegalStateException, IOException {
        write(xmlSerializer, book.getMetadata().getIdentifiers(), book.getTitle(),
                book.getMetadata().getAuthors(), book.getTableOfContents());
    }
    /**
     * 写入
     *
     * @param serializer      serializer
     * @param identifiers     identifiers
     * @param title           title
     * @param authors         authors
     * @param tableOfContents tableOfContents
     */
    @SuppressWarnings("unused")
    public static void write(XmlSerializer serializer,
                             List<Identifier> identifiers, String title, List<Author> authors,
                             TableOfContents tableOfContents) throws IllegalArgumentException, IllegalStateException, IOException {
        serializer.startDocument(Constants.CHARACTER_ENCODING, false);
        serializer.setPrefix(EpubWriter.EMPTY_NAMESPACE_PREFIX, NAMESPACE_XHTML);
        serializer.startTag(NAMESPACE_XHTML, XHTMLTgs.html);
        serializer.attribute(EpubWriter.EMPTY_NAMESPACE_PREFIX, XHTMLAttributes.xmlns_epub, NAMESPACE_EPUB);
        serializer.attribute(EpubWriter.EMPTY_NAMESPACE_PREFIX, XHTMLAttributes.xml_lang, XHTMLAttributeValues.lang);
        serializer.attribute(EpubWriter.EMPTY_NAMESPACE_PREFIX, XHTMLAttributes.lang, LANGUAGE);
        //写入头部head标签
        writeHead(title, serializer);
        //body开始
        serializer.startTag(NAMESPACE_XHTML, XHTMLTgs.body);
        //h1开始
        serializer.startTag(NAMESPACE_XHTML, XHTMLTgs.h1);
        serializer.text(title);
        serializer.endTag(NAMESPACE_XHTML, XHTMLTgs.h1);
        //h1关闭
        //nav开始
        serializer.startTag(NAMESPACE_XHTML, XHTMLTgs.nav);
        serializer.attribute("", XHTMLAttributes.epub_type, XHTMLAttributeValues.epub_type);
        serializer.attribute("", XHTMLAttributes.id, XHTMLAttributeValues.epub_type);
        serializer.attribute("", XHTMLAttributes.role, XHTMLAttributeValues.role_toc);
        //h2开始
        serializer.startTag(NAMESPACE_XHTML, XHTMLTgs.h2);
        serializer.text("目录");
        serializer.endTag(NAMESPACE_XHTML, XHTMLTgs.h2);
        writeNavPoints(tableOfContents.getTocReferences(), 1, serializer);
        serializer.endTag(NAMESPACE_XHTML, XHTMLTgs.nav);
        //body关闭
        serializer.endTag(NAMESPACE_XHTML, XHTMLTgs.body);
        serializer.endTag(NAMESPACE_XHTML, XHTMLTgs.html);
        serializer.endDocument();
    }
    private static int writeNavPoints(List<TOCReference> tocReferences,
                                      int playOrder,
                                      XmlSerializer serializer) throws IOException {
        writeOlStart(serializer);
        for (TOCReference tocReference : tocReferences) {
            if (tocReference.getResource() == null) {
                playOrder = writeNavPoints(tocReference.getChildren(), playOrder,
                        serializer);
                continue;
            }
            writeNavPointStart(tocReference, serializer);
            playOrder++;
            if (!tocReference.getChildren().isEmpty()) {
                playOrder = writeNavPoints(tocReference.getChildren(), playOrder,
                        serializer);
            }
            writeNavPointEnd(tocReference, serializer);
        }
        writeOlSEnd(serializer);
        return playOrder;
    }
    private static void writeNavPointStart(TOCReference tocReference, XmlSerializer serializer) throws IOException {
        writeLiStart(serializer);
        String title = tocReference.getTitle();
        String href = tocReference.getCompleteHref();
        if (StringUtil.isNotBlank(href)) {
            writeLabel(title, href, serializer);
        } else {
            writeLabel(title, serializer);
        }
    }
    @SuppressWarnings("unused")
    private static void writeNavPointEnd(TOCReference tocReference,
                                         XmlSerializer serializer) throws IOException {
        writeLiEnd(serializer);
    }
    protected static void writeLabel(String title, String href, XmlSerializer serializer) throws IOException {
        serializer.startTag(NAMESPACE_XHTML, XHTMLTgs.a);
        serializer.attribute("", XHTMLAttributes.href, href);
        //attribute必须在Text之前设置。
        serializer.text(title);
        //serializer.attribute(NAMESPACE_XHTML, XHTMLAttributes.href, href);
        serializer.endTag(NAMESPACE_XHTML, XHTMLTgs.a);
    }
    protected static void writeLabel(String title, XmlSerializer serializer) throws IOException {
        serializer.startTag(NAMESPACE_XHTML, XHTMLTgs.span);
        serializer.text(title);
        serializer.endTag(NAMESPACE_XHTML, XHTMLTgs.span);
    }
    private static void writeLiStart(XmlSerializer serializer) throws IOException {
        serializer.startTag(NAMESPACE_XHTML, XHTMLTgs.li);
        Log.d(TAG, "writeLiStart");
    }
    private static void writeLiEnd(XmlSerializer serializer) throws IOException {
        serializer.endTag(NAMESPACE_XHTML, XHTMLTgs.li);
        Log.d(TAG, "writeLiEND");
    }
    private static void writeOlStart(XmlSerializer serializer) throws IOException {
        serializer.startTag(NAMESPACE_XHTML, XHTMLTgs.ol);
        Log.d(TAG, "writeOlStart");
    }
    private static void writeOlSEnd(XmlSerializer serializer) throws IOException {
        serializer.endTag(NAMESPACE_XHTML, XHTMLTgs.ol);
        Log.d(TAG, "writeOlEnd");
    }
    private static void writeHead(String title, XmlSerializer serializer) throws IOException {
        serializer.startTag(NAMESPACE_XHTML, XHTMLTgs.head);
        //title
        serializer.startTag(NAMESPACE_XHTML, XHTMLTgs.title);
        serializer.text(StringUtil.defaultIfNull(title));
        serializer.endTag(NAMESPACE_XHTML, XHTMLTgs.title);
        //link
        serializer.startTag(NAMESPACE_XHTML, XHTMLTgs.link);
        serializer.attribute("", XHTMLAttributes.rel, "stylesheet");
        serializer.attribute("", XHTMLAttributes.type, "text/css");
        serializer.attribute("", XHTMLAttributes.href, "css/style.css");
        serializer.endTag(NAMESPACE_XHTML, XHTMLTgs.link);
        //meta
        serializer.startTag(NAMESPACE_XHTML, XHTMLTgs.meta);
        serializer.attribute("", XHTMLAttributes.http_equiv, XHTMLAttributeValues.Content_Type);
        serializer.attribute("", XHTMLAttributes.content, XHTMLAttributeValues.HTML_UTF8);
        serializer.endTag(NAMESPACE_XHTML, XHTMLTgs.meta);
        serializer.endTag(NAMESPACE_XHTML, XHTMLTgs.head);
    }
--- a/epublib/src/main/java/me/ag2s/epublib/epub/PackageDocumentBase.java
+++ b/epublib/src/main/java/me/ag2s/epublib/epub/PackageDocumentBase.java
@ -14,8 +14,11 @@ public class PackageDocumentBase {
  public static final String NAMESPACE_DUBLIN_CORE = "http://purl.org/dc/elements/1.1/";
  public static final String PREFIX_DUBLIN_CORE = "dc";
  //public static final String PREFIX_OPF = "opf";
-  //Some Epub Reader not reconize opt:packge,So just let it empty;
+  //在EPUB3标准中，packge前面没有opf头，一些epub阅读器也不支持opf头。
  //Some Epub Reader not reconize op:packge,So just let it empty;
  public static final String PREFIX_OPF = "";
  //添加 version 变量来区分Epub文件的版本
  //Add the version field to distinguish the version of EPUB file
  public static final String version="version";
  public static final String dateFormat = "yyyy-MM-dd";
@ -76,6 +79,10 @@ public class PackageDocumentBase {
    String version = "version";
    String scheme = "scheme";
    String property = "property";
    //add for epub3
    /**
     * add for epub3
     */
    String properties="properties";
  }
--- a/epublib/src/main/java/me/ag2s/epublib/epub/PackageDocumentMetadataReader.java
+++ b/epublib/src/main/java/me/ag2s/epublib/epub/PackageDocumentMetadataReader.java
@ -2,21 +2,23 @@ package me.ag2s.epublib.epub;
 import android.util.Log;
-import me.ag2s.epublib.domain.Author;
+import org.w3c.dom.Document;
-import me.ag2s.epublib.domain.Date;
+import org.w3c.dom.Element;
-import me.ag2s.epublib.domain.Identifier;
+import org.w3c.dom.Node;
-import me.ag2s.epublib.domain.Metadata;
+import org.w3c.dom.NodeList;
-import me.ag2s.epublib.util.StringUtil;
+
 //import io.documentnode.minilog.Logger;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import javax.xml.namespace.QName;
-import org.w3c.dom.Document;
+
-import org.w3c.dom.Element;
+import me.ag2s.epublib.domain.Author;
-import org.w3c.dom.Node;
+import me.ag2s.epublib.domain.Date;
-import org.w3c.dom.NodeList;
+import me.ag2s.epublib.domain.Identifier;
 import me.ag2s.epublib.domain.Metadata;
 import me.ag2s.epublib.util.StringUtil;
 /**
 * Reads the package document metadata.
@ -28,7 +30,7 @@ import org.w3c.dom.NodeList;
 // package
 class PackageDocumentMetadataReader extends PackageDocumentBase {
-  private static String TAG= PackageDocumentMetadataReader.class.getName();
+  private static final String TAG= PackageDocumentMetadataReader.class.getName();
  public static Metadata readMetadata(Document packageDocument) {
    Metadata result = new Metadata();
@ -76,12 +78,12 @@ class PackageDocumentMetadataReader extends PackageDocumentBase {
  /**
   * consumes meta tags that have a property attribute as defined in the standard. For example:
   * &lt;meta property="rendition:layout"&gt;pre-paginated&lt;/meta&gt;
-   * @param metadataElement
+   * @param metadataElement metadataElement
-   * @return
+   * @return Map<QName, String>
   */
  private static Map<QName, String> readOtherProperties(
      Element metadataElement) {
-    Map<QName, String> result = new HashMap<QName, String>();
+    Map<QName, String> result = new HashMap<>();
    NodeList metaTags = metadataElement.getElementsByTagName(OPFTags.meta);
    for (int i = 0; i < metaTags.getLength(); i++) {
@ -101,12 +103,12 @@ class PackageDocumentMetadataReader extends PackageDocumentBase {
  /**
   * consumes meta tags that have a property attribute as defined in the standard. For example:
   * &lt;meta property="rendition:layout"&gt;pre-paginated&lt;/meta&gt;
-   * @param metadataElement
+   * @param metadataElement metadataElement
-   * @return
+   * @return Map<String, String>
   */
  private static Map<String, String> readMetaProperties(
      Element metadataElement) {
-    Map<String, String> result = new HashMap<String, String>();
+    Map<String, String> result = new HashMap<>();
    NodeList metaTags = metadataElement.getElementsByTagName(OPFTags.meta);
    for (int i = 0; i < metaTags.getLength(); i++) {
@ -126,9 +128,8 @@ class PackageDocumentMetadataReader extends PackageDocumentBase {
    if (packageElement == null) {
      return null;
    }
-    String result = packageElement
+    return packageElement
        .getAttributeNS(NAMESPACE_OPF, OPFAttributes.uniqueIdentifier);
    return result;
  }
  private static List<Author> readCreators(Element metadataElement) {
@ -143,7 +144,7 @@ class PackageDocumentMetadataReader extends PackageDocumentBase {
      Element metadataElement) {
    NodeList elements = metadataElement
        .getElementsByTagNameNS(NAMESPACE_DUBLIN_CORE, authorTag);
-    List<Author> result = new ArrayList<Author>(elements.getLength());
+    List<Author> result = new ArrayList<>(elements.getLength());
    for (int i = 0; i < elements.getLength(); i++) {
      Element authorElement = (Element) elements.item(i);
      Author author = createAuthor(authorElement);
@ -158,7 +159,7 @@ class PackageDocumentMetadataReader extends PackageDocumentBase {
  private static List<Date> readDates(Element metadataElement) {
    NodeList elements = metadataElement
        .getElementsByTagNameNS(NAMESPACE_DUBLIN_CORE, DCTags.date);
-    List<Date> result = new ArrayList<Date>(elements.getLength());
+    List<Date> result = new ArrayList<>(elements.getLength());
    for (int i = 0; i < elements.getLength(); i++) {
      Element dateElement = (Element) elements.item(i);
      Date date;
@ -198,10 +199,10 @@ class PackageDocumentMetadataReader extends PackageDocumentBase {
        .getElementsByTagNameNS(NAMESPACE_DUBLIN_CORE, DCTags.identifier);
    if (identifierElements.getLength() == 0) {
      Log.e(TAG,"Package does not contain element " + DCTags.identifier);
-      return new ArrayList<Identifier>();
+      return new ArrayList<>();
    }
    String bookIdId = getBookIdId(metadataElement.getOwnerDocument());
-    List<Identifier> result = new ArrayList<Identifier>(
+    List<Identifier> result = new ArrayList<>(
            identifierElements.getLength());
    for (int i = 0; i < identifierElements.getLength(); i++) {
      Element identifierElement = (Element) identifierElements.item(i);
--- a/epublib/src/main/java/me/ag2s/epublib/epub/PackageDocumentMetadataWriter.java
+++ b/epublib/src/main/java/me/ag2s/epublib/epub/PackageDocumentMetadataWriter.java
@ -1,32 +1,29 @@
 package me.ag2s.epublib.epub;
 import org.xmlpull.v1.XmlSerializer;
 import java.io.IOException;
 import java.util.List;
 import java.util.Map;
 import javax.xml.namespace.QName;
 import me.ag2s.epublib.Constants;
 import me.ag2s.epublib.domain.Author;
 import me.ag2s.epublib.domain.Book;
 import me.ag2s.epublib.domain.Date;
 import me.ag2s.epublib.domain.EpubBook;
 import me.ag2s.epublib.domain.Identifier;
 import me.ag2s.epublib.util.StringUtil;
 import java.io.IOException;
 import java.util.List;
 import java.util.Map;
 import javax.xml.namespace.QName;
 import org.xmlpull.v1.XmlSerializer;
 public class PackageDocumentMetadataWriter extends PackageDocumentBase {
  /**
   * Writes the book's metadata.
   *
-   * @param book
+   * @param book book
-   * @param serializer
+   * @param serializer serializer
-   * @throws IOException
+   * @throws  IOException IOException
-   * @throws IllegalStateException
+   * @throws  IllegalStateException IllegalStateException
-   * @throws IllegalArgumentException
+   * @throws IllegalArgumentException IllegalArgumentException
   */
-  public static void writeMetaData(EpubBook book, XmlSerializer serializer)
+  public static void writeMetaData(Book book, XmlSerializer serializer)
      throws IllegalArgumentException, IllegalStateException, IOException {
    serializer.startTag(NAMESPACE_OPF, OPFTags.metadata);
    serializer.setPrefix(PREFIX_DUBLIN_CORE, NAMESPACE_DUBLIN_CORE);
@ -117,7 +114,7 @@ public class PackageDocumentMetadataWriter extends PackageDocumentBase {
        OPFValues.generator);
    serializer
        .attribute(EpubWriter.EMPTY_NAMESPACE_PREFIX, OPFAttributes.content,
-            Constants.EPUB4J_GENERATOR_NAME);
+            Constants.EPUB_GENERATOR_NAME);
    serializer.endTag(NAMESPACE_OPF, OPFTags.meta);
    serializer.endTag(NAMESPACE_OPF, OPFTags.metadata);
@ -142,11 +139,10 @@ public class PackageDocumentMetadataWriter extends PackageDocumentBase {
   * The first identifier for which the bookId is true is made the bookId identifier.
   * If no identifier has bookId == true then the first bookId identifier is written as the primary.
   *
-   * @param identifiers
+   * @param identifiers identifiers
-   * @param serializer
+   * @param serializer serializer
-   * @throws IOException
+   * @throws IllegalStateException e
-   * @throws IllegalStateException
+   * @throws IllegalArgumentException e
   * @throws IllegalArgumentException
   * @
   */
  private static void writeIdentifiers(List<Identifier> identifiers,
--- a/epublib/src/main/java/me/ag2s/epublib/epub/PackageDocumentReader.java
+++ b/epublib/src/main/java/me/ag2s/epublib/epub/PackageDocumentReader.java
@ -19,10 +19,8 @@ import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import javax.xml.parsers.ParserConfigurationException;
 import me.ag2s.epublib.Constants;
-import me.ag2s.epublib.domain.EpubBook;
+import me.ag2s.epublib.domain.Book;
 import me.ag2s.epublib.domain.Guide;
 import me.ag2s.epublib.domain.GuideReference;
 import me.ag2s.epublib.domain.MediaType;
@ -34,8 +32,6 @@ import me.ag2s.epublib.domain.SpineReference;
 import me.ag2s.epublib.util.ResourceUtil;
 import me.ag2s.epublib.util.StringUtil;
 //import io.documentnode.minilog.Logger;
 /**
 * Reads the opf package document as defined by namespace http://www.idpf.org/2007/opf
 *
@ -44,22 +40,22 @@ import me.ag2s.epublib.util.StringUtil;
 */
 public class PackageDocumentReader extends PackageDocumentBase {
-  private static String TAG= PackageDocumentReader.class.getName();
+  private static final String TAG= PackageDocumentReader.class.getName();
  private static final String[] POSSIBLE_NCX_ITEM_IDS = new String[]{"toc",
      "ncx", "ncxtoc","htmltoc"};
  public static void read(
-          Resource packageResource, EpubReader epubReader, EpubBook book,
+      Resource packageResource, EpubReader epubReader, Book book,
      Resources resources)
-      throws UnsupportedEncodingException, SAXException, IOException, ParserConfigurationException {
+      throws SAXException, IOException {
    Document packageDocument = ResourceUtil.getAsDocument(packageResource);
    String packageHref = packageResource.getHref();
    resources = fixHrefs(packageHref, resources);
    readGuide(packageDocument, epubReader, book, resources);
    // Books sometimes use non-identifier ids. We map these here to legal ones
-    Map<String, String> idMapping = new HashMap<String, String>();
+    Map<String, String> idMapping = new HashMap<>();
    String version=DOMUtil.getAttribute(packageDocument.getDocumentElement(),PREFIX_OPF,PackageDocumentBase.version);
    resources = readManifest(packageDocument, packageHref, epubReader,
@ -90,13 +86,14 @@ public class PackageDocumentReader extends PackageDocumentBase {
  /**
   * Reads the manifest containing the resource ids, hrefs and mediatypes.
   *
-   * @param packageDocument
+   * @param packageDocument e
-   * @param packageHref
+   * @param packageHref e
-   * @param epubReader
+   * @param epubReader e
-   * @param resources
+   * @param resources e
-   * @param idMapping
+   * @param idMapping e
   * @return a Map with resources, with their id's as key.
   */
  @SuppressWarnings("unused")
  private static Resources readManifest(Document packageDocument,
      String packageHref,
      EpubReader epubReader, Resources resources,
@ -118,7 +115,7 @@ public class PackageDocumentReader extends PackageDocumentBase {
          .getAttribute(itemElement, NAMESPACE_OPF, OPFAttributes.id);
      String href = DOMUtil
          .getAttribute(itemElement, NAMESPACE_OPF, OPFAttributes.href);
-      String properties=DOMUtil.getAttribute(itemElement,NAMESPACE_OPF,OPFAttributes.properties);
+
      try {
        href = URLDecoder.decode(href, Constants.CHARACTER_ENCODING);
      } catch (UnsupportedEncodingException e) {
@ -132,7 +129,10 @@ public class PackageDocumentReader extends PackageDocumentBase {
        continue;
      }
      resource.setId(id);
      //for epub3
      String properties=DOMUtil.getAttribute(itemElement,NAMESPACE_OPF,OPFAttributes.properties);
      resource.setProperties(properties);
      MediaType mediaType = MediaTypes.getMediaTypeByName(mediaTypeName);
      if (mediaType != null) {
        resource.setMediaType(mediaType);
@ -148,13 +148,14 @@ public class PackageDocumentReader extends PackageDocumentBase {
   * Reads the book's guide.
   * Here some more attempts are made at finding the cover page.
   *
-   * @param packageDocument
+   * @param packageDocument r
-   * @param epubReader
+   * @param epubReader  r
-   * @param book
+   * @param book r
-   * @param resources
+   * @param resources g
   */
  @SuppressWarnings("unused")
  private static void readGuide(Document packageDocument,
-                                EpubReader epubReader, EpubBook book, Resources resources) {
+      EpubReader epubReader, Book book, Resources resources) {
    Element guideElement = DOMUtil
        .getFirstElementByTagNameNS(packageDocument.getDocumentElement(),
            NAMESPACE_OPF, OPFTags.guide);
@ -204,8 +205,8 @@ public class PackageDocumentReader extends PackageDocumentBase {
   * Example:
   * If the packageHref is "OEBPS/content.opf" then a resource href like "OEBPS/foo/bar.html" will be turned into "foo/bar.html"
   *
-   * @param packageHref
+   * @param packageHref f
-   * @param resourcesByHref
+   * @param resourcesByHref g
   * @return The stripped package href
   */
  static Resources fixHrefs(String packageHref,
@ -228,9 +229,9 @@ public class PackageDocumentReader extends PackageDocumentBase {
  /**
   * Reads the document's spine, containing all sections in reading order.
   *
-   * @param packageDocument
+   * @param packageDocument b
-   * @param resources
+   * @param resources b
-   * @param idMapping
+   * @param idMapping b
   * @return the document's spine, containing all sections in reading order.
   */
  private static Spine readSpine(Document packageDocument, Resources resources,
@ -251,7 +252,7 @@ public class PackageDocumentReader extends PackageDocumentBase {
        .setTocResource(findTableOfContentsResource(tocResourceId, resources));
    NodeList spineNodes = packageDocument
        .getElementsByTagNameNS(NAMESPACE_OPF, OPFTags.itemref);
-    List<SpineReference> spineReferences = new ArrayList<SpineReference>(
+    List<SpineReference> spineReferences = new ArrayList<>(
            spineNodes.getLength());
    for (int i = 0; i < spineNodes.getLength(); i++) {
      Element spineItem = (Element) spineNodes.item(i);
@ -267,7 +268,7 @@ public class PackageDocumentReader extends PackageDocumentBase {
      }
      Resource resource = resources.getByIdOrHref(id);
      if (resource == null) {
-        Log.e(TAG,"resource with id \'" + id + "\' not found");
+        Log.e(TAG, "resource with id '" + id + "' not found");
        continue;
      }
@ -286,13 +287,12 @@ public class PackageDocumentReader extends PackageDocumentBase {
   * Creates a spine out of all resources in the resources.
   * The generated spine consists of all XHTML pages in order of their href.
   *
-   * @param resources
+   * @param resources f
   * @return a spine created out of all resources in the resources.
   */
  private static Spine generateSpineFromResources(Resources resources) {
    Spine result = new Spine();
-    List<String> resourceHrefs = new ArrayList<String>();
+    List<String> resourceHrefs = new ArrayList<>(resources.getAllHrefs());
    resourceHrefs.addAll(resources.getAllHrefs());
    Collections.sort(resourceHrefs, String.CASE_INSENSITIVE_ORDER);
    for (String resourceHref : resourceHrefs) {
      Resource resource = resources.getByHref(resourceHref);
@ -312,8 +312,8 @@ public class PackageDocumentReader extends PackageDocumentBase {
   * Here we try several ways of finding this table of contents resource.
   * We try the given attribute value, some often-used ones and finally look through all resources for the first resource with the table of contents mimetype.
   *
-   * @param tocResourceId
+   * @param tocResourceId g
-   * @param resources
+   * @param resources g
   * @return the Resource containing the table of contents
   */
  static Resource findTableOfContentsResource(String tocResourceId,
@ -331,13 +331,13 @@ public class PackageDocumentReader extends PackageDocumentBase {
    tocResource = resources.findFirstResourceByMediaType(MediaTypes.NCX);
    if (tocResource == null) {
-      for (int i = 0; i < POSSIBLE_NCX_ITEM_IDS.length; i++) {
+      for (String possibleNcxItemId : POSSIBLE_NCX_ITEM_IDS) {
-        tocResource = resources.getByIdOrHref(POSSIBLE_NCX_ITEM_IDS[i]);
+        tocResource = resources.getByIdOrHref(possibleNcxItemId);
        if (tocResource != null) {
          break;
        }
        tocResource = resources
-            .getByIdOrHref(POSSIBLE_NCX_ITEM_IDS[i].toUpperCase());
+                .getByIdOrHref(possibleNcxItemId.toUpperCase());
        if (tocResource != null) {
          break;
        }
@ -363,13 +363,13 @@ public class PackageDocumentReader extends PackageDocumentBase {
   * Find all resources that have something to do with the coverpage and the cover image.
   * Search the meta tags and the guide references
   *
-   * @param packageDocument
+   * @param packageDocument s
   * @return all resources that have something to do with the coverpage and the cover image.
   */
  // package
  static Set<String> findCoverHrefs(Document packageDocument) {
-    Set<String> result = new HashSet<String>();
+    Set<String> result = new HashSet<>();
    // try and find a meta tag with name = 'cover' and a non-blank id
    String coverResourceId = DOMUtil
@ -403,18 +403,16 @@ public class PackageDocumentReader extends PackageDocumentBase {
  /**
   * Finds the cover resource in the packageDocument and adds it to the book if found.
   * Keeps the cover resource in the resources map
-   *
+   * @param packageDocument s
-   * @param packageDocument
+   * @param book x
   * @param book
   * @1param resources
   */
-  private static void readCover(Document packageDocument, EpubBook book) {
+  private static void readCover(Document packageDocument, Book book) {
    Collection<String> coverHrefs = findCoverHrefs(packageDocument);
    for (String coverHref : coverHrefs) {
      Resource resource = book.getResources().getByHref(coverHref);
      if (resource == null) {
-        Log.e(TAG, "Cover resource " + coverHref + " not found");
+        Log.e(TAG,"Cover resource " + coverHref + " not found");
        continue;
      }
      if (resource.getMediaType() == MediaTypes.XHTML) {
--- a/epublib/src/main/java/me/ag2s/epublib/epub/PackageDocumentWriter.java
+++ b/epublib/src/main/java/me/ag2s/epublib/epub/PackageDocumentWriter.java
@ -2,16 +2,8 @@ package me.ag2s.epublib.epub;
 import android.util.Log;
 import org.xmlpull.v1.XmlSerializer;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;
 import me.ag2s.epublib.Constants;
-import me.ag2s.epublib.domain.EpubBook;
+import me.ag2s.epublib.domain.Book;
 import me.ag2s.epublib.domain.Guide;
 import me.ag2s.epublib.domain.GuideReference;
 import me.ag2s.epublib.domain.MediaTypes;
@ -20,22 +12,24 @@ import me.ag2s.epublib.domain.Spine;
 import me.ag2s.epublib.domain.SpineReference;
 import me.ag2s.epublib.util.StringUtil;
-//import io.documentnode.minilog.Logger;
+import java.io.IOException;
-//import javax.xml.stream.XMLStreamException;
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import org.xmlpull.v1.XmlSerializer;
 /**
 * Writes the opf package document as defined by namespace http://www.idpf.org/2007/opf
 *
 * @author paul
 *
 */
 public class PackageDocumentWriter extends PackageDocumentBase {
-  //private static final Logger log = Logger.create(PackageDocumentWriter.class);
+    private static final String TAG = PackageDocumentWriter.class.getName();
  private static String TAG= PackageDocumentWriter.class.getName();
    public static void write(EpubWriter epubWriter, XmlSerializer serializer,
-                           EpubBook book) throws IOException {
+                             Book book) {
        try {
            serializer.startDocument(Constants.CHARACTER_ENCODING, false);
            serializer.setPrefix(PREFIX_OPF, NAMESPACE_OPF);
@ -43,7 +37,7 @@ public class PackageDocumentWriter extends PackageDocumentBase {
            serializer.startTag(NAMESPACE_OPF, OPFTags.packageTag);
            serializer
                    .attribute(EpubWriter.EMPTY_NAMESPACE_PREFIX, OPFAttributes.version,
-                      "2.0");
+                            book.getVersion());
            serializer.attribute(EpubWriter.EMPTY_NAMESPACE_PREFIX,
                    OPFAttributes.uniqueIdentifier, BOOK_ID_ID);
@ -57,7 +51,6 @@ public class PackageDocumentWriter extends PackageDocumentBase {
            serializer.endDocument();
            serializer.flush();
        } catch (IOException e) {
      // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
@ -65,15 +58,15 @@ public class PackageDocumentWriter extends PackageDocumentBase {
    /**
     * Writes the package's spine.
     *
-   * @param book
+     * @param book e
-   * @param epubWriter
+     * @param epubWriter g
-   * @param serializer
+     * @param serializer g
-   * @throws IOException
+     * @throws IOException g
-   * @throws IllegalStateException
+     * @throws IllegalStateException g
-   * @throws IllegalArgumentException
+     * @throws IllegalArgumentException 1@throws XMLStreamException
   * 1@throws XMLStreamException
     */
-  private static void writeSpine(EpubBook book, EpubWriter epubWriter,
+    @SuppressWarnings("unused")
    private static void writeSpine(Book book, EpubWriter epubWriter,
                                   XmlSerializer serializer)
            throws IllegalArgumentException, IllegalStateException, IOException {
        serializer.startTag(NAMESPACE_OPF, OPFTags.spine);
@ -100,19 +93,26 @@ public class PackageDocumentWriter extends PackageDocumentBase {
    }
-  private static void writeManifest(EpubBook book, EpubWriter epubWriter,
+    private static void writeManifest(Book book, EpubWriter epubWriter,
                                      XmlSerializer serializer)
            throws IllegalArgumentException, IllegalStateException, IOException {
        serializer.startTag(NAMESPACE_OPF, OPFTags.manifest);
        serializer.startTag(NAMESPACE_OPF, OPFTags.item);
        //For EPUB3
        if (book.isEpub3()) {
            serializer.attribute(EpubWriter.EMPTY_NAMESPACE_PREFIX, OPFAttributes.properties,NCXDocumentV3.V3_NCX_PROPERTIES);
            serializer.attribute(EpubWriter.EMPTY_NAMESPACE_PREFIX, OPFAttributes.id, NCXDocumentV3.NCX_ITEM_ID);
            serializer.attribute(EpubWriter.EMPTY_NAMESPACE_PREFIX, OPFAttributes.href, NCXDocumentV3.DEFAULT_NCX_HREF);
            serializer.attribute(EpubWriter.EMPTY_NAMESPACE_PREFIX, OPFAttributes.media_type, NCXDocumentV3.V3_NCX_MEDIATYPE.getName());
        } else {
            serializer.attribute(EpubWriter.EMPTY_NAMESPACE_PREFIX, OPFAttributes.id,
                    epubWriter.getNcxId());
-    serializer.attribute(EpubWriter.EMPTY_NAMESPACE_PREFIX, OPFAttributes.href,
+            serializer.attribute(EpubWriter.EMPTY_NAMESPACE_PREFIX, OPFAttributes.href, epubWriter.getNcxHref());
-            epubWriter.getNcxHref());
+            serializer.attribute(EpubWriter.EMPTY_NAMESPACE_PREFIX, OPFAttributes.media_type, epubWriter.getNcxMediaType());
-    serializer
+        }
-            .attribute(EpubWriter.EMPTY_NAMESPACE_PREFIX, OPFAttributes.media_type,
+
            epubWriter.getNcxMediaType());
        serializer.endTag(NAMESPACE_OPF, OPFTags.item);
 //		writeCoverResources(book, serializer);
@ -124,29 +124,23 @@ public class PackageDocumentWriter extends PackageDocumentBase {
        serializer.endTag(NAMESPACE_OPF, OPFTags.manifest);
    }
-  private static List<Resource> getAllResourcesSortById(EpubBook book) {
+    private static List<Resource> getAllResourcesSortById(Book book) {
-    List<Resource> allResources = new ArrayList<Resource>(
+        List<Resource> allResources = new ArrayList<>(
                book.getResources().getAll());
-    Collections.sort(allResources, new Comparator<Resource>() {
+        Collections.sort(allResources, (resource1, resource2) -> resource1.getId().compareToIgnoreCase(resource2.getId()));
      @Override
      public int compare(Resource resource1, Resource resource2) {
        return resource1.getId().compareToIgnoreCase(resource2.getId());
      }
    });
        return allResources;
    }
    /**
     * Writes a resources as an item element
     *
-   * @param resource
+     * @param resource g
-   * @param serializer
+     * @param serializer g
-   * @throws IOException
+     * @throws IOException g
-   * @throws IllegalStateException
+     * @throws IllegalStateException g
     * @throws IllegalArgumentException 1@throws XMLStreamException
     */
-  private static void writeItem(EpubBook book, Resource resource,
+    private static void writeItem(Book book, Resource resource,
                                  XmlSerializer serializer)
            throws IllegalArgumentException, IllegalStateException, IOException {
        if (resource == null ||
@ -164,14 +158,14 @@ public class PackageDocumentWriter extends PackageDocumentBase {
        if (StringUtil.isBlank(resource.getHref())) {
 //      log.error("resource href must not be empty (id: " + resource.getId()
 //          + ", mediatype:" + resource.getMediaType() + ")");
-      Log.e(TAG,"resource href must not be empty (id: " + resource.getId()
+            Log.e(TAG, "resource href must not be empty (id: " + resource.getId()
                    + ", mediatype:" + resource.getMediaType() + ")");
            return;
        }
        if (resource.getMediaType() == null) {
 //      log.error("resource mediatype must not be empty (id: " + resource.getId()
 //          + ", href:" + resource.getHref() + ")");
-      Log.e(TAG,"resource mediatype must not be empty (id: " + resource.getId()
+            Log.e(TAG, "resource mediatype must not be empty (id: " + resource.getId()
                    + ", href:" + resource.getHref() + ")");
            return;
        }
@ -188,10 +182,12 @@ public class PackageDocumentWriter extends PackageDocumentBase {
    /**
     * List all spine references
-   * @throws IOException
+     *
-   * @throws IllegalStateException
+     * @throws IOException f
-   * @throws IllegalArgumentException
+     * @throws IllegalStateException f
     * @throws IllegalArgumentException f
     */
    @SuppressWarnings("unused")
    private static void writeSpineItems(Spine spine, XmlSerializer serializer)
            throws IllegalArgumentException, IllegalStateException, IOException {
        for (SpineReference spineReference : spine.getSpineReferences()) {
@ -208,7 +204,7 @@ public class PackageDocumentWriter extends PackageDocumentBase {
        }
    }
-  private static void writeGuide(EpubBook book, EpubWriter epubWriter,
+    private static void writeGuide(Book book, EpubWriter epubWriter,
                                   XmlSerializer serializer)
            throws IllegalArgumentException, IllegalStateException, IOException {
        serializer.startTag(NAMESPACE_OPF, OPFTags.guide);
@ -220,6 +216,7 @@ public class PackageDocumentWriter extends PackageDocumentBase {
        serializer.endTag(NAMESPACE_OPF, OPFTags.guide);
    }
    @SuppressWarnings("unused")
    private static void ensureCoverPageGuideReferenceWritten(Guide guide,
                                                             EpubWriter epubWriter, XmlSerializer serializer)
            throws IllegalArgumentException, IllegalStateException, IOException {
--- a/epublib/src/main/java/me/ag2s/epublib/epub/ResourcesLoader.java
+++ b/epublib/src/main/java/me/ag2s/epublib/epub/ResourcesLoader.java
@ -11,9 +11,10 @@ import me.ag2s.epublib.domain.Resource;
 import me.ag2s.epublib.domain.Resources;
 import me.ag2s.epublib.util.CollectionUtil;
 import me.ag2s.epublib.util.ResourceUtil;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Enumeration;
 import java.util.List;
 import java.util.zip.ZipEntry;
@ -26,25 +27,24 @@ import java.util.zip.ZipInputStream;
 * Loads Resources from inputStreams, ZipFiles, etc
 *
 * @author paul
 *
 */
 public class ResourcesLoader {
-  private static String TAG=ResourceUtil.class.getName();
+    private static final String TAG = ResourcesLoader.class.getName();
    /**
     * Loads the entries of the zipFile as resources.
-   *
+     * <p>
     * The MediaTypes that are in the lazyLoadedTypes will not get their
     * contents loaded, but are stored as references to entries into the
     * ZipFile and are loaded on demand by the Resource system.
     *
-   * @param zipFile
+     * @param zipFile             import epub zipfile
-   * @param defaultHtmlEncoding
+     * @param defaultHtmlEncoding epub xhtml default encoding
-   * @param lazyLoadedTypes
+     * @param lazyLoadedTypes     lazyLoadedTypes
-   * @return
+     * @return Resources
-   * @throws IOException
+     * @throws IOException IOException
     */
    public static Resources loadResources(ZipFile zipFile,
                                          String defaultHtmlEncoding,
@ -87,8 +87,8 @@ public class ResourcesLoader {
     * Whether the given href will load a mediaType that is in the
     * collection of lazilyLoadedMediaTypes.
     *
-   * @param href
+     * @param href                   href
-   * @param lazilyLoadedMediaTypes
+     * @param lazilyLoadedMediaTypes lazilyLoadedMediaTypes
     * @return Whether the given href will load a mediaType that is
     * in the collection of lazilyLoadedMediaTypes.
     */
@ -103,15 +103,15 @@ public class ResourcesLoader {
    /**
     * Loads all entries from the ZipInputStream as Resources.
-   *
+     * <p>
     * Loads the contents of all ZipEntries into memory.
     * Is fast, but may lead to memory problems when reading large books
     * on devices with small amounts of memory.
     *
-   * @param zipInputStream
+     * @param zipInputStream      zipInputStream
-   * @param defaultHtmlEncoding
+     * @param defaultHtmlEncoding defaultHtmlEncoding
-   * @return
+     * @return Resources
-   * @throws IOException
+     * @throws IOException IOException
     */
    public static Resources loadResources(ZipInputStream zipInputStream,
                                          String defaultHtmlEncoding) throws IOException {
@ -145,7 +145,7 @@ public class ResourcesLoader {
            //when reading a file that is not a real zip archive or a zero length file, zipInputStream.getNextEntry()
            //throws an exception and does not advance, so loadResources enters an infinite loop
            //log.error("Invalid or damaged zip file.", e);
-      Log.e(TAG,"",e);
+            Log.e(TAG, e.getLocalizedMessage());
            try {
                zipInputStream.closeEntry();
            } catch (Exception ignored) {
@ -156,18 +156,18 @@ public class ResourcesLoader {
    /**
     * Loads all entries from the ZipInputStream as Resources.
-   *
+     * <p>
     * Loads the contents of all ZipEntries into memory.
     * Is fast, but may lead to memory problems when reading large books
     * on devices with small amounts of memory.
     *
-   * @param zipFile
+     * @param zipFile             zipFile
-   * @param defaultHtmlEncoding
+     * @param defaultHtmlEncoding defaultHtmlEncoding
-   * @return
+     * @return Resources
-   * @throws IOException
+     * @throws IOException IOException
     */
-  public static Resources loadResources(ZipFile zipFile,
+    public static Resources loadResources(ZipFile zipFile, String defaultHtmlEncoding) throws IOException {
-      String defaultHtmlEncoding) throws IOException {
+        List<MediaType> ls = new ArrayList<>();
-    return loadResources(zipFile, defaultHtmlEncoding, Collections.emptyList());
+        return loadResources(zipFile, defaultHtmlEncoding, ls);
    }
 }
--- a/epublib/src/main/java/me/ag2s/epublib/util/CollectionUtil.java
+++ b/epublib/src/main/java/me/ag2s/epublib/util/CollectionUtil.java
@ -15,7 +15,7 @@ public class CollectionUtil {
   */
  private static class IteratorEnumerationAdapter<T> implements Enumeration<T> {
-    private Iterator<T> iterator;
+    private final Iterator<T> iterator;
    public IteratorEnumerationAdapter(Iterator<T> iter) {
      this.iterator = iter;
@ -34,21 +34,22 @@ public class CollectionUtil {
  /**
   * Creates an Enumeration out of the given Iterator.
-   * @param <T>
+   * @param <T>  g
-   * @param it
+   * @param it g
   * @return an Enumeration created out of the given Iterator.
   */
  @SuppressWarnings("unused")
  public static <T> Enumeration<T> createEnumerationFromIterator(
      Iterator<T> it) {
-    return new IteratorEnumerationAdapter<T>(it);
+    return new IteratorEnumerationAdapter<>(it);
  }
  /**
   * Returns the first element of the list, null if the list is null or empty.
   *
-   * @param <T>
+   * @param <T> f
-   * @param list
+   * @param list f
   * @return the first element of the list, null if the list is null or empty.
   */
  public static <T> T first(List<T> list) {
@ -61,7 +62,7 @@ public class CollectionUtil {
  /**
   * Whether the given collection is null or has no elements.
   *
-   * @param collection
+   * @param collection g
   * @return Whether the given collection is null or has no elements.
   */
  public static boolean isEmpty(Collection<?> collection) {
--- a/epublib/src/main/java/me/ag2s/epublib/util/IOUtil.java
+++ b/epublib/src/main/java/me/ag2s/epublib/util/IOUtil.java
@ -23,10 +23,10 @@ public class IOUtil {
  /**
   * Gets the contents of the Reader as a byte[], with the given character encoding.
   *
-   * @param in
+   * @param in g
-   * @param encoding
+   * @param encoding g
   * @return the contents of the Reader as a byte[], with the given character encoding.
-   * @throws IOException
+   * @throws IOException g
   */
  public static byte[] toByteArray(Reader in, String encoding)
      throws IOException {
@ -39,9 +39,9 @@ public class IOUtil {
  /**
   * Returns the contents of the InputStream as a byte[]
   *
-   * @param in
+   * @param in f
   * @return the contents of the InputStream as a byte[]
-   * @throws IOException
+   * @throws IOException f
   */
  public static byte[] toByteArray(InputStream in) throws IOException {
    ByteArrayOutputStream result = new ByteArrayOutputStream();
@ -59,7 +59,7 @@ public class IOUtil {
   * @param in the stream to read data from
   * @param size the size of the array to create
   * @return the array, or null
-   * @throws IOException
+   * @throws IOException f
   */
  public static byte[] toByteArray(InputStream in, int size)
      throws IOException {
@ -89,8 +89,8 @@ public class IOUtil {
   * (nrRead + totalNrRead) &lt; Integer.MAX_VALUE then nrRead + totalNrRead
   * is returned, -1 otherwise.
   *
-   * @param nrRead
+   * @param nrRead f
-   * @param totalNrNread
+   * @param totalNrNread f
   * @return if totalNrRead &lt; 0 then totalNrRead is returned, if
   *    (nrRead + totalNrRead) &lt; Integer.MAX_VALUE then nrRead + totalNrRead
   *    is returned, -1 otherwise.
@ -109,15 +109,15 @@ public class IOUtil {
  /**
   * Copies the contents of the InputStream to the OutputStream.
   *
-   * @param in
+   * @param in f
-   * @param out
+   * @param out f
   * @return the nr of bytes read, or -1 if the amount &gt; Integer.MAX_VALUE
-   * @throws IOException
+   * @throws IOException f
   */
  public static int copy(InputStream in, OutputStream out)
      throws IOException {
    byte[] buffer = new byte[IO_COPY_BUFFER_SIZE];
-    int readSize = -1;
+    int readSize ;
    int result = 0;
    while ((readSize = in.read(buffer)) >= 0) {
      out.write(buffer, 0, readSize);
@ -130,14 +130,14 @@ public class IOUtil {
  /**
   * Copies the contents of the Reader to the Writer.
   *
-   * @param in
+   * @param in f
-   * @param out
+   * @param out f
   * @return the nr of characters read, or -1 if the amount &gt; Integer.MAX_VALUE
-   * @throws IOException
+   * @throws IOException f
   */
  public static int copy(Reader in, Writer out) throws IOException {
    char[] buffer = new char[IO_COPY_BUFFER_SIZE];
-    int readSize = -1;
+    int readSize;
    int result = 0;
    while ((readSize = in.read(buffer)) >= 0) {
      out.write(buffer, 0, readSize);
@ -148,7 +148,7 @@ public class IOUtil {
  }
  public static String Stream2String(InputStream inputStream) {
-    String str="";
+    String str;
    try {
      BufferedInputStream bis = new BufferedInputStream(inputStream);
      ByteArrayOutputStream buf = new ByteArrayOutputStream();
--- a/epublib/src/main/java/me/ag2s/epublib/util/NoCloseOutputStream.java
+++ b/epublib/src/main/java/me/ag2s/epublib/util/NoCloseOutputStream.java
@ -11,9 +11,10 @@ import java.io.OutputStream;
 *
 * @author paul
 */
@SuppressWarnings("unused")
 public class NoCloseOutputStream extends OutputStream {
-  private OutputStream outputStream;
+  private final OutputStream outputStream;
  public NoCloseOutputStream(OutputStream outputStream) {
    this.outputStream = outputStream;
--- a/epublib/src/main/java/me/ag2s/epublib/util/NoCloseWriter.java
+++ b/epublib/src/main/java/me/ag2s/epublib/util/NoCloseWriter.java
@ -11,16 +11,17 @@ import java.io.Writer;
 *
 * @author paul
 */
@SuppressWarnings("unused")
 public class NoCloseWriter extends Writer {
-  private Writer writer;
+  private final Writer writer;
  public NoCloseWriter(Writer writer) {
    this.writer = writer;
  }
  @Override
-  public void close() throws IOException {
+  public void close() {
  }
  @Override
--- a/epublib/src/main/java/me/ag2s/epublib/util/ResourceUtil.java
+++ b/epublib/src/main/java/me/ag2s/epublib/util/ResourceUtil.java
@ -1,10 +1,9 @@
 package me.ag2s.epublib.util;
-import me.ag2s.epublib.Constants;
+import org.w3c.dom.Document;
-import me.ag2s.epublib.domain.MediaType;
+import org.xml.sax.InputSource;
-import me.ag2s.epublib.domain.Resource;
+import org.xml.sax.SAXException;
-import me.ag2s.epublib.epub.EpubProcessorSupport;
+
 import me.ag2s.epublib.domain.MediaTypes;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
@ -15,11 +14,12 @@ import java.util.zip.ZipEntry;
 import java.util.zip.ZipInputStream;
 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.ParserConfigurationException;
-import org.w3c.dom.Document;
+import me.ag2s.epublib.Constants;
-import org.xml.sax.InputSource;
+import me.ag2s.epublib.domain.MediaType;
-import org.xml.sax.SAXException;
+import me.ag2s.epublib.domain.MediaTypes;
 import me.ag2s.epublib.domain.Resource;
 import me.ag2s.epublib.epub.EpubProcessorSupport;
 /**
 * Various resource utility methods
@ -29,58 +29,61 @@ import org.xml.sax.SAXException;
 public class ResourceUtil {
    public static Resource createHTMLResource(String title, String string) {
-    String html=createHtml(title,string);
+        String html = createHtml(title, string);
        MediaType mediaTypeProperty = MediaTypes.XHTML;
        byte[] data = html.getBytes();
-    Resource result = new Resource(data, mediaTypeProperty);
+        return new Resource(data, mediaTypeProperty);
    return result;
    }
-  public static Resource createHTMLResource(String title, String string,String href) {
+
-    String html=createHtml(title,string);
+    @SuppressWarnings("unused")
    public static Resource createHTMLResource(String title, String string, String href) {
        String html = createHtml(title, string);
        MediaType mediaTypeProperty = MediaTypes.XHTML;
        byte[] data = html.getBytes();
-    Resource result = new Resource(null,data,href ,mediaTypeProperty);
+        return new Resource(null, data, href, mediaTypeProperty);
-    return result;
+    }
-  }
+
-  private static String createHtml(String title,String txt){
+    @SuppressWarnings("unused")
-    StringBuilder body= new StringBuilder();
+    private static String createHtml(String title, String txt) {
-    for(String s:txt.split("\\r?\\n")){
+        StringBuilder body = new StringBuilder();
-      s=s.trim();
+        for (String s : txt.split("\\r?\\n")) {
-      if(s!=null&&s.length()!=0) {
+            s = s.trim();
            if (s.length() != 0) {
                body.append("<p>").append(s).append("</p>");
            }
        }
-    String html="<?xml version=\"1.0\" encoding=\"utf-8\"?>";
+        String html = "<?xml version=\"1.0\" encoding=\"utf-8\"?>";
-    html+="<html xmlns=\"http://www.w3.org/1999/xhtml\" xmlns:epub=\"http://www.idpf.org/2007/ops\">";
+        html += "<html xmlns=\"http://www.w3.org/1999/xhtml\" xmlns:epub=\"http://www.idpf.org/2007/ops\">";
-    html+="<head><title>"+title+"</title>" +
+        html += "<head><title>" + title + "</title>" +
                "<link rel=\"stylesheet\" type=\"text/css\" href=\"css/style.css\"/>" +
                "<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\"/></head>";
-    html+="<body><h1>"+title+"</h1>" +
+        html += "<body><h1>" + title + "</h1>" +
-            body+
+                body +
                "</body></html>";
        return html;
    }
    @SuppressWarnings("unused")
    public static Resource createResource(File file) throws IOException {
        if (file == null) {
            return null;
        }
        MediaType mediaType = MediaTypes.determineMediaType(file.getName());
        byte[] data = IOUtil.toByteArray(new FileInputStream(file));
-    Resource result = new Resource(data, mediaType);
+        return new Resource(data, mediaType);
    return result;
    }
    /**
     * Creates a resource with as contents a html page with the given title.
     *
-   * @param title
+     * @param title v
-   * @param href
+     * @param href  v
     * @return a resource with as contents a html page with the given title.
     */
    @SuppressWarnings("unused")
    public static Resource createResource(String title, String href) {
        String content =
                "<html><head><title>" + title + "</title></head><body><h1>" + title
@ -92,10 +95,10 @@ public class ResourceUtil {
    /**
     * Creates a resource out of the given zipEntry and zipInputStream.
     *
-   * @param zipEntry
+     * @param zipEntry       v
-   * @param zipInputStream
+     * @param zipInputStream v
     * @return a resource created out of the given zipEntry and zipInputStream.
-   * @throws IOException
+     * @throws IOException v
     */
    public static Resource createResource(ZipEntry zipEntry,
                                          ZipInputStream zipInputStream) throws IOException {
@ -112,12 +115,13 @@ public class ResourceUtil {
    /**
     * Converts a given string from given input character encoding to the requested output character encoding.
     *
-   * @param inputEncoding
+     * @param inputEncoding  v
-   * @param outputEncoding
+     * @param outputEncoding v
-   * @param input
+     * @param input          v
     * @return the string from given input character encoding converted to the requested output character encoding.
-   * @throws UnsupportedEncodingException
+     * @throws UnsupportedEncodingException v
     */
    @SuppressWarnings("unused")
    public static byte[] recode(String inputEncoding, String outputEncoding,
                                byte[] input) throws UnsupportedEncodingException {
        return new String(input, inputEncoding).getBytes(outputEncoding);
@ -125,8 +129,8 @@ public class ResourceUtil {
    /**
     * Gets the contents of the Resource as an InputSource in a null-safe manner.
   *
     */
    @SuppressWarnings("unused")
    public static InputSource getInputSource(Resource resource)
            throws IOException {
        if (resource == null) {
@ -136,8 +140,7 @@ public class ResourceUtil {
        if (reader == null) {
            return null;
        }
-    InputSource inputSource = new InputSource(reader);
+        return new InputSource(reader);
    return inputSource;
    }
@ -145,7 +148,7 @@ public class ResourceUtil {
     * Reads parses the xml therein and returns the result as a Document
     */
    public static Document getAsDocument(Resource resource)
-      throws SAXException, IOException, ParserConfigurationException {
+            throws SAXException, IOException {
        return getAsDocument(resource,
                EpubProcessorSupport.createDocumentBuilder());
    }
@ -153,22 +156,20 @@ public class ResourceUtil {
    /**
     * Reads the given resources inputstream, parses the xml therein and returns the result as a Document
     *
-   * @param resource
+     * @param resource        v
-   * @param documentBuilder
+     * @param documentBuilder v
     * @return the document created from the given resource
-   * @throws UnsupportedEncodingException
+     * @throws UnsupportedEncodingException v
-   * @throws SAXException
+     * @throws SAXException                 v
-   * @throws IOException
+     * @throws IOException                  v
   * @throws ParserConfigurationException
     */
    public static Document getAsDocument(Resource resource,
                                         DocumentBuilder documentBuilder)
-      throws UnsupportedEncodingException, SAXException, IOException, ParserConfigurationException {
+            throws UnsupportedEncodingException, SAXException, IOException {
        InputSource inputSource = getInputSource(resource);
        if (inputSource == null) {
            return null;
        }
-    Document result = documentBuilder.parse(inputSource);
+        return documentBuilder.parse(inputSource);
    return result;
    }
 }
--- a/epublib/src/main/java/me/ag2s/epublib/util/StreamWriterDelegate.txt
+++ b/epublib/src/main/java/me/ag2s/epublib/util/StreamWriterDelegate.txt
@ -1,202 +0,0 @@
 package me.ag2s.epublib.util;
 /*
 * Copyright (c) 2006, John Kristian
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *      *   Redistributions of source code must retain the above copyright
 *          notice, this list of conditions and the following disclaimer.
 *
 *      *   Redistributions in binary form must reproduce the above copyright
 *          notice, this list of conditions and the following disclaimer in the
 *          documentation and/or other materials provided with the distribution.
 *
 *      *   Neither the name of StAX-Utils nor the names of its contributors
 *          may be used to endorse or promote products derived from this
 *          software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 */
 import javax.xml.namespace.NamespaceContext;
 import javax.xml.stream.XMLStreamException;
 import javax.xml.stream.XMLStreamWriter;
 /**
 * Abstract class for writing filtered XML streams. This class provides methods
 * that merely delegate to the contained stream. Subclasses should override some
 * of these methods, and may also provide additional methods and fields.
 *
 * @author <a href="mailto:jk2006@engineer.com">John Kristian</a>
 */
 public abstract class StreamWriterDelegate implements XMLStreamWriter {
  protected StreamWriterDelegate(XMLStreamWriter out) {
    this.out = out;
  }
  protected XMLStreamWriter out;
  public Object getProperty(String name)
      throws IllegalArgumentException {
    return out.getProperty(name);
  }
  public NamespaceContext getNamespaceContext() {
    return out.getNamespaceContext();
  }
  public void setNamespaceContext(NamespaceContext context)
      throws XMLStreamException {
    out.setNamespaceContext(context);
  }
  public void setDefaultNamespace(String uri)
      throws XMLStreamException {
    out.setDefaultNamespace(uri);
  }
  public void writeStartDocument() throws XMLStreamException {
    out.writeStartDocument();
  }
  public void writeStartDocument(String version)
      throws XMLStreamException {
    out.writeStartDocument(version);
  }
  public void writeStartDocument(String encoding, String version)
      throws XMLStreamException {
    out.writeStartDocument(encoding, version);
  }
  public void writeDTD(String dtd) throws XMLStreamException {
    out.writeDTD(dtd);
  }
  public void writeProcessingInstruction(String target)
      throws XMLStreamException {
    out.writeProcessingInstruction(target);
  }
  public void writeProcessingInstruction(String target, String data)
      throws XMLStreamException {
    out.writeProcessingInstruction(target, data);
  }
  public void writeComment(String data) throws XMLStreamException {
    out.writeComment(data);
  }
  public void writeEmptyElement(String localName)
      throws XMLStreamException {
    out.writeEmptyElement(localName);
  }
  public void writeEmptyElement(String namespaceURI, String localName)
      throws XMLStreamException {
    out.writeEmptyElement(namespaceURI, localName);
  }
  public void writeEmptyElement(String prefix, String localName,
      String namespaceURI) throws XMLStreamException {
    out.writeEmptyElement(prefix, localName, namespaceURI);
  }
  public void writeStartElement(String localName)
      throws XMLStreamException {
    out.writeStartElement(localName);
  }
  public void writeStartElement(String namespaceURI, String localName)
      throws XMLStreamException {
    out.writeStartElement(namespaceURI, localName);
  }
  public void writeStartElement(String prefix, String localName,
      String namespaceURI) throws XMLStreamException {
    out.writeStartElement(prefix, localName, namespaceURI);
  }
  public void writeDefaultNamespace(String namespaceURI)
      throws XMLStreamException {
    out.writeDefaultNamespace(namespaceURI);
  }
  public void writeNamespace(String prefix, String namespaceURI)
      throws XMLStreamException {
    out.writeNamespace(prefix, namespaceURI);
  }
  public String getPrefix(String uri) throws XMLStreamException {
    return out.getPrefix(uri);
  }
  public void setPrefix(String prefix, String uri)
      throws XMLStreamException {
    out.setPrefix(prefix, uri);
  }
  public void writeAttribute(String localName, String value)
      throws XMLStreamException {
    out.writeAttribute(localName, value);
  }
  public void writeAttribute(String namespaceURI, String localName,
      String value) throws XMLStreamException {
    out.writeAttribute(namespaceURI, localName, value);
  }
  public void writeAttribute(String prefix, String namespaceURI,
      String localName, String value) throws XMLStreamException {
    out.writeAttribute(prefix, namespaceURI, localName, value);
  }
  public void writeCharacters(String text) throws XMLStreamException {
    out.writeCharacters(text);
  }
  public void writeCharacters(char[] text, int start, int len)
      throws XMLStreamException {
    out.writeCharacters(text, start, len);
  }
  public void writeCData(String data) throws XMLStreamException {
    out.writeCData(data);
  }
  public void writeEntityRef(String name) throws XMLStreamException {
    out.writeEntityRef(name);
  }
  public void writeEndElement() throws XMLStreamException {
    out.writeEndElement();
  }
  public void writeEndDocument() throws XMLStreamException {
    out.writeEndDocument();
  }
  public void flush() throws XMLStreamException {
    out.flush();
  }
  public void close() throws XMLStreamException {
    out.close();
  }
 }
--- a/epublib/src/main/java/me/ag2s/epublib/util/StringUtil.java
+++ b/epublib/src/main/java/me/ag2s/epublib/util/StringUtil.java
@ -6,14 +6,13 @@ import java.util.List;
 /**
 * Various String utility functions.
- *
+ * <p>
 * Most of the functions herein are re-implementations of the ones in apache
 * commons StringUtils. The reason for re-implementing this is that the
 * functions are fairly simple and using my own implementation saves the
 * inclusion of a 200Kb jar file.
 *
 * @author paul.siegmann
 *
 */
 public class StringUtil {
@ -22,12 +21,12 @@ public class StringUtil {
     * doesn't. X/foo/../Y is changed into 'X/Y', etc. Does not handle invalid
     * paths like "../".
     *
-   * @param path
+     * @param path path
     * @return the normalized path
     */
    public static String collapsePathDots(String path) {
        String[] stringParts = path.split("/");
-    List<String> parts = new ArrayList<String>(Arrays.asList(stringParts));
+        List<String> parts = new ArrayList<>(Arrays.asList(stringParts));
        for (int i = 0; i < parts.size() - 1; i++) {
            String currentDir = parts.get(i);
            if (currentDir.length() == 0 || currentDir.equals(".")) {
@ -56,7 +55,7 @@ public class StringUtil {
     * Whether the String is not null, not zero-length and does not contain of
     * only whitespace.
     *
-   * @param text
+     * @param text text
     * @return Whether the String is not null, not zero-length and does not contain of
     */
    public static boolean isNotBlank(String text) {
@ -94,8 +93,8 @@ public class StringUtil {
     * Whether the given source string ends with the given suffix, ignoring
     * case.
     *
-   * @param source
+     * @param source source
-   * @param suffix
+     * @param suffix suffix
     * @return Whether the given source string ends with the given suffix, ignoring case.
     */
    public static boolean endsWithIgnoreCase(String source, String suffix) {
@ -115,7 +114,7 @@ public class StringUtil {
    /**
     * If the given text is null return "", the original text otherwise.
     *
-   * @param text
+     * @param text text
     * @return If the given text is null "", the original text otherwise.
     */
    public static String defaultIfNull(String text) {
@ -125,8 +124,8 @@ public class StringUtil {
    /**
     * If the given text is null return "", the given defaultValue otherwise.
     *
-   * @param text
+     * @param text         d
-   * @param defaultValue
+     * @param defaultValue d
     * @return If the given text is null "", the given defaultValue otherwise.
     */
    public static String defaultIfNull(String text, String defaultValue) {
@ -139,8 +138,8 @@ public class StringUtil {
    /**
     * Null-safe string comparator
     *
-   * @param text1
+     * @param text1 d
-   * @param text2
+     * @param text2 d
     * @return whether the two strings are equal
     */
    public static boolean equals(String text1, String text2) {
@ -153,7 +152,7 @@ public class StringUtil {
    /**
     * Pretty toString printer.
     *
-   * @param keyValues
+     * @param keyValues d
     * @return a string representation of the input values
     */
    public static String toString(Object... keyValues) {
@ -183,20 +182,20 @@ public class StringUtil {
    public static int hashCode(String... values) {
        int result = 31;
-    for (int i = 0; i < values.length; i++) {
+        for (String value : values) {
-      result ^= String.valueOf(values[i]).hashCode();
+            result ^= String.valueOf(value).hashCode();
        }
        return result;
    }
    /**
     * Gives the substring of the given text before the given separator.
-   *
+     * <p>
     * If the text does not contain the given separator then the given text is
     * returned.
     *
-   * @param text
+     * @param text      d
-   * @param separator
+     * @param separator d
     * @return the substring of the given text before the given separator.
     */
    public static String substringBefore(String text, char separator) {
@ -213,12 +212,12 @@ public class StringUtil {
    /**
     * Gives the substring of the given text before the last occurrence of the
     * given separator.
-   *
+     * <p>
     * If the text does not contain the given separator then the given text is
     * returned.
     *
-   * @param text
+     * @param text      d
-   * @param separator
+     * @param separator d
     * @return the substring of the given text before the last occurrence of the given separator.
     */
    public static String substringBeforeLast(String text, char separator) {
@ -235,11 +234,11 @@ public class StringUtil {
    /**
     * Gives the substring of the given text after the last occurrence of the
     * given separator.
-   *
+     * <p>
     * If the text does not contain the given separator then "" is returned.
     *
-   * @param text
+     * @param text      d
-   * @param separator
+     * @param separator d
     * @return the substring of the given text after the last occurrence of the given separator.
     */
    public static String substringAfterLast(String text, char separator) {
@ -255,7 +254,7 @@ public class StringUtil {
    /**
     * Gives the substring of the given text after the given separator.
-   *
+     * <p>
     * If the text does not contain the given separator then "" is returned.
     *
     * @param text the input text
--- a/epublib/src/main/java/me/ag2s/epublib/util/commons/io/BOMInputStream.java
+++ b/epublib/src/main/java/me/ag2s/epublib/util/commons/io/BOMInputStream.java
@ -85,6 +85,7 @@ public class BOMInputStream extends ProxyInputStream {
     * a {@link ByteOrderMark#UTF_8} BOM.
     * @param delegate the InputStream to delegate to
     */
    @SuppressWarnings("unused")
    public BOMInputStream(InputStream delegate) {
        this(delegate, false, ByteOrderMark.UTF_8);
    }
@ -96,6 +97,7 @@ public class BOMInputStream extends ProxyInputStream {
     * @param include true to include the UTF-8 BOM or
     * false to exclude it
     */
    @SuppressWarnings("unused")
    public BOMInputStream(InputStream delegate, boolean include) {
        this(delegate, include, ByteOrderMark.UTF_8);
    }
@ -106,6 +108,7 @@ public class BOMInputStream extends ProxyInputStream {
     * @param delegate the InputStream to delegate to
     * @param boms The BOMs to detect and exclude
     */
    @SuppressWarnings("unused")
    public BOMInputStream(InputStream delegate, ByteOrderMark... boms) {
        this(delegate, false, boms);
    }
@ -118,6 +121,7 @@ public class BOMInputStream extends ProxyInputStream {
     * false to exclude them
     * @param boms The BOMs to detect and optionally exclude
     */
    @SuppressWarnings("unused")
    public BOMInputStream(InputStream delegate, boolean include, ByteOrderMark... boms) {
        super(delegate);
        if (boms == null || boms.length == 0) {
@ -134,6 +138,7 @@ public class BOMInputStream extends ProxyInputStream {
     * if it does not
     * @throws IOException if an error reading the first bytes of the stream occurs
     */
    @SuppressWarnings("unused")
    public boolean hasBOM() throws IOException {
        return (getBOM() != null);
    }
@ -148,6 +153,7 @@ public class BOMInputStream extends ProxyInputStream {
     * is configured to detect
     * @throws IOException if an error reading the first bytes of the stream occurs
     */
    @SuppressWarnings("unused")
    public boolean hasBOM(ByteOrderMark bom) throws IOException {
        if (!boms.contains(bom)) {
            throw new IllegalArgumentException("Stream not configure to detect " + bom);
--- a/epublib/src/main/java/me/ag2s/epublib/util/commons/io/ByteOrderMark.java
+++ b/epublib/src/main/java/me/ag2s/epublib/util/commons/io/ByteOrderMark.java
@ -150,6 +150,7 @@ public class ByteOrderMark implements Serializable {
     * @return the length of the BOM's bytes
     */
    @Override
    @SuppressWarnings("NullableProblems")
    public String toString() {
        StringBuilder builder = new StringBuilder();
        builder.append(getClass().getSimpleName());
--- a/epublib/src/main/java/me/ag2s/epublib/util/commons/io/ProxyInputStream.java
+++ b/epublib/src/main/java/me/ag2s/epublib/util/commons/io/ProxyInputStream.java
@ -197,9 +197,9 @@ public abstract class ProxyInputStream extends FilterInputStream {
     *
     * @since Commons IO 2.0
     * @param n number of bytes that the caller asked to be read
     * @throws IOException if the pre-processing fails
     */
-    protected void beforeRead(int n) throws IOException {
+    @SuppressWarnings("unused")
    protected void beforeRead(int n) {
    }
    /**
@ -217,9 +217,9 @@ public abstract class ProxyInputStream extends FilterInputStream {
     *
     * @since Commons IO 2.0
     * @param n number of bytes read, or -1 if the end of stream was reached
     * @throws IOException if the post-processing fails
     */
-    protected void afterRead(int n) throws IOException {
+    @SuppressWarnings("unused")
    protected void afterRead(int n) {
    }
    /**
--- a/epublib/src/main/java/me/ag2s/epublib/util/commons/io/XmlStreamReader.java
+++ b/epublib/src/main/java/me/ag2s/epublib/util/commons/io/XmlStreamReader.java
@ -30,6 +30,7 @@ import java.net.HttpURLConnection;
 import java.net.URL;
 import java.net.URLConnection;
 import java.text.MessageFormat;
 import java.util.Objects;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@ -105,6 +106,7 @@ public class XmlStreamReader extends Reader {
     *
     * @return the default encoding to use.
     */
    @SuppressWarnings("unused")
    public String getDefaultEncoding() {
        return defaultEncoding;
    }
@ -121,6 +123,7 @@ public class XmlStreamReader extends Reader {
     * @param file File to create a Reader from.
     * @throws IOException thrown if there is a problem reading the file.
     */
    @SuppressWarnings("unused")
    public XmlStreamReader(File file) throws IOException {
        this(new FileInputStream(file));
    }
@ -224,6 +227,7 @@ public class XmlStreamReader extends Reader {
     * @throws IOException thrown if there is a problem reading the stream of
     *         the URL.
     */
    @SuppressWarnings("unused")
    public XmlStreamReader(URL url) throws IOException {
        this(url.openConnection(), null);
    }
@ -249,15 +253,16 @@ public class XmlStreamReader extends Reader {
     */
    public XmlStreamReader(URLConnection conn, String defaultEncoding) throws IOException {
        this.defaultEncoding = defaultEncoding;
        @SuppressWarnings("unused")
        boolean lenient = true;
        String contentType = conn.getContentType();
        InputStream is = conn.getInputStream();
        BOMInputStream bom = new BOMInputStream(new BufferedInputStream(is, BUFFER_SIZE), false, BOMS);
        BOMInputStream pis = new BOMInputStream(bom, true, XML_GUESS_BYTES);
        if (conn instanceof HttpURLConnection || contentType != null) {
-            this.encoding = doHttpStream(bom, pis, contentType, lenient);
+            this.encoding = doHttpStream(bom, pis, contentType, true);
        } else {
-            this.encoding = doRawStream(bom, pis, lenient);
+            this.encoding = doRawStream(bom, pis, true);
        }
        this.reader = new InputStreamReader(pis, encoding);
    }
@ -509,11 +514,11 @@ public class XmlStreamReader extends Reader {
        // BOM is UTF-8
        if (bomEnc.equals(UTF_8)) {
            if (xmlGuessEnc != null && !xmlGuessEnc.equals(UTF_8)) {
-                String msg = MessageFormat.format(RAW_EX_1, new Object[] { bomEnc, xmlGuessEnc, xmlEnc });
+                String msg = MessageFormat.format(RAW_EX_1, bomEnc, xmlGuessEnc, xmlEnc);
                throw new XmlStreamReaderException(msg, bomEnc, xmlGuessEnc, xmlEnc);
            }
            if (xmlEnc != null && !xmlEnc.equals(UTF_8)) {
-                String msg = MessageFormat.format(RAW_EX_1, new Object[] { bomEnc, xmlGuessEnc, xmlEnc });
+                String msg = MessageFormat.format(RAW_EX_1, bomEnc, xmlGuessEnc, xmlEnc);
                throw new XmlStreamReaderException(msg, bomEnc, xmlGuessEnc, xmlEnc);
            }
            return bomEnc;
@ -522,18 +527,18 @@ public class XmlStreamReader extends Reader {
        // BOM is UTF-16BE or UTF-16LE
        if (bomEnc.equals(UTF_16BE) || bomEnc.equals(UTF_16LE)) {
            if (xmlGuessEnc != null && !xmlGuessEnc.equals(bomEnc)) {
-                String msg = MessageFormat.format(RAW_EX_1, new Object[] { bomEnc, xmlGuessEnc, xmlEnc });
+                String msg = MessageFormat.format(RAW_EX_1, bomEnc, xmlGuessEnc, xmlEnc);
                throw new XmlStreamReaderException(msg, bomEnc, xmlGuessEnc, xmlEnc);
            }
            if (xmlEnc != null && !xmlEnc.equals(UTF_16) && !xmlEnc.equals(bomEnc)) {
-                String msg = MessageFormat.format(RAW_EX_1, new Object[] { bomEnc, xmlGuessEnc, xmlEnc });
+                String msg = MessageFormat.format(RAW_EX_1, bomEnc, xmlGuessEnc, xmlEnc);
                throw new XmlStreamReaderException(msg, bomEnc, xmlGuessEnc, xmlEnc);
            }
            return bomEnc;
        }
        // BOM is something else
-        String msg = MessageFormat.format(RAW_EX_2, new Object[] { bomEnc, xmlGuessEnc, xmlEnc });
+        String msg = MessageFormat.format(RAW_EX_2, bomEnc, xmlGuessEnc, xmlEnc);
        throw new XmlStreamReaderException(msg, bomEnc, xmlGuessEnc, xmlEnc);
    }
@ -697,7 +702,7 @@ public class XmlStreamReader extends Reader {
                }
                Matcher m = ENCODING_PATTERN.matcher(prolog);
                if (m.find()) {
-                    encoding = m.group(1).toUpperCase();
+                    encoding = Objects.requireNonNull(m.group(1)).toUpperCase();
                    encoding = encoding.substring(1, encoding.length() - 1);
                }
            }
--- a/epublib/src/main/java/me/ag2s/epublib/util/commons/io/XmlStreamReaderException.java
+++ b/epublib/src/main/java/me/ag2s/epublib/util/commons/io/XmlStreamReaderException.java
@ -120,6 +120,7 @@ public class XmlStreamReaderException extends IOException {
     * @return the MIME type in the content-type, null if there was not
     *         content-type or the encoding detection did not involve HTTP.
     */
    @SuppressWarnings("unused")
    public String getContentTypeMime() {
        return contentTypeMime;
    }