Java tutorial
/** * This work is licensed under the Creative Commons Attribution-NonCommercial- * NoDerivs 3.0 Unported License. To view a copy of this license, visit * http://creativecommons.org/licenses/by-nc-nd/3.0/ or send a letter to * Creative Commons, 444 Castro Street, Suite 900, Mountain View, California, * 94041, USA. * * Use of this work is permitted only in accordance with license rights granted. * Materials provided "AS IS"; no representations or warranties provided. * * Copyright 2012 Marcus Parkkinen, Aki Kkel, Fredrik hs. **/ package edu.chalmers.dat255.audiobookplayer.model; import java.io.Serializable; import java.util.Collection; import java.util.Collections; import java.util.LinkedList; import java.util.List; import org.apache.commons.lang.builder.EqualsBuilder; import org.apache.commons.lang.builder.HashCodeBuilder; import edu.chalmers.dat255.audiobookplayer.constants.Constants; import edu.chalmers.dat255.audiobookplayer.interfaces.IBookUpdates; /** * Represents a collection of Track objects. Null tracks are not allowed (and * will be ignored when added). * * @author Marcus Parkkinen, Aki Kkel * @version 0.6 */ public final class Book implements IBookUpdates, Serializable { private static final String TAG = "Book.java"; private static final int NO_TRACK_SELECTED = Constants.Value.NO_TRACK_SELECTED; private static final long serialVersionUID = 2; private List<Track> tracks; private int selectedTrackIndex = NO_TRACK_SELECTED; private String author; // immutable private String title; private int duration; /** * Used when no author is given. * * @param title * The title of the book. */ public Book(String title) { this(title, Constants.Message.NO_AUTHOR); } /** * Creates an empty book with the given title and author. */ public Book(String title, String author) { tracks = new LinkedList<Track>(); setSelectedBookTitle(title); // when a book is created, it should be ensured that the author is // appropriate. if (author == null || author.isEmpty()) { this.author = Constants.Message.NO_AUTHOR; } else { this.author = author; } } /** * Creates a book from the referenced collection of Tracks. This constructor * assumes that the provided collection holds tracks. * * @param col * The collection of tracks. * @param title * The title of the book. * @param author * The author of the book. */ public Book(Collection<Track> col, String title, String author) { this(title, author); for (Track t : col) { if (t != null) { tracks.add(t); duration += t.getDuration(); } } // adjust the track index now that we have tracks selectedTrackIndex = 0; } /** * Copy constructor. * * @param original * The book to copy. */ public Book(Book original) { this(original.getSelectedBookTitle(), original.getSelectedBookAuthor()); // copy primitive member variables this.duration = original.duration; this.selectedTrackIndex = original.selectedTrackIndex; setAuthor(original.getSelectedBookAuthor()); // also create deep copies of the tracks for (Track t : original.tracks) { this.tracks.add(new Track(t)); } } /** * Creates a book from the referenced collection of Tracks. * * @param col * Collection of tracks. * @param title * Title of the book. */ public Book(Collection<Track> col, String title) { this(col, title, Constants.Message.NO_AUTHOR); } /* IBookUpdates */ /* * (non-Javadoc) * * @see * edu.chalmers.dat255.audiobookplayer.interfaces.IBookUpdates#removeTrack * (int) */ public void removeTrack(int trackIndex) { checkTrackIndexLegal(trackIndex); // remove the track and adjust the duration duration -= tracks.remove(trackIndex).getDuration(); // check whether this was the last track if (tracks.size() == 0) { setSelectedTrackIndex(NO_TRACK_SELECTED); } else { if (trackIndex < selectedTrackIndex) { // adjust the index if we removed one earlier in the list selectedTrackIndex--; } else if (trackIndex == selectedTrackIndex) { // if we removed the selected one then mark the first selectedTrackIndex = 0; } } } /* * (non-Javadoc) * * @see * edu.chalmers.dat255.audiobookplayer.interfaces.IBookUpdates#addTrack( * edu.chalmers.dat255.audiobookplayer.model.Track) */ public void addTrack(Track t) { if (t != null) { // add the track tracks.add(t); // adjust the duration duration += t.getDuration(); if (tracks.size() == 1) { selectedTrackIndex = 0; } } } /* * (non-Javadoc) * * @see * edu.chalmers.dat255.audiobookplayer.interfaces.IBookUpdates#swapTracks * (int, int) */ public void swapTracks(int firstIndex, int secondIndex) { checkTrackIndexLegal(firstIndex); checkTrackIndexLegal(secondIndex); Collections.swap(tracks, firstIndex, secondIndex); } /* * (non-Javadoc) * * @see * edu.chalmers.dat255.audiobookplayer.interfaces.IBookUpdates#moveTrack * (int, int) */ public void moveTrack(int fromIndex, int toIndex) { checkTrackIndexLegal(fromIndex); checkTrackIndexLegal(toIndex); Track t = tracks.remove(fromIndex); tracks.add(toIndex, t); } /* * (non-Javadoc) * * @see edu.chalmers.dat255.audiobookplayer.interfaces.IBookUpdates# * setSelectedTrackIndex(int) */ public void setSelectedTrackIndex(int index) { if (index < -1 || index > this.tracks.size() + 1) { throw new IndexOutOfBoundsException(TAG + " setSelectedTrackIndex with index out of bounds: " + index + ", list size: " + this.tracks.size()); } selectedTrackIndex = index; } /* * (non-Javadoc) * * @see edu.chalmers.dat255.audiobookplayer.interfaces.IBookUpdates# * setSelectedBookTitle(java.lang.String) */ public void setSelectedBookTitle(String title) { if (title == null) { throw new IllegalArgumentException(TAG + " setBookTitle to null title is illegal"); } this.title = title; } /* * (non-Javadoc) * * @see edu.chalmers.dat255.audiobookplayer.interfaces.IBookUpdates# * updateBookDuration() */ public void updateSelectedBookDuration() { this.duration = 0; for (Track t : tracks) { this.duration += t.getDuration(); } } /* * (non-Javadoc) * * @see edu.chalmers.dat255.audiobookplayer.interfaces.IBookUpdates# * getSelectedBookAuthor() */ public String getSelectedBookAuthor() { return author; } /* * (non-Javadoc) * * @see edu.chalmers.dat255.audiobookplayer.interfaces.IBookUpdates# * getSelectedBookTitle() */ public String getSelectedBookTitle() { return title; } /* End IBookUpdates */ /** * @param author * The author to set to. */ private void setAuthor(String author) { this.author = author; } /* ITrackUpdates */ /* * (non-Javadoc) * * @see edu.chalmers.dat255.audiobookplayer.interfaces.ITrackUpdates# * setSelectedTrackElapsedTime(int) */ public void setSelectedTrackElapsedTime(int newTime) { checkTrackIndexLegal(selectedTrackIndex); this.tracks.get(selectedTrackIndex).setSelectedTrackElapsedTime(newTime); } /* * (non-Javadoc) * * @see * edu.chalmers.dat255.audiobookplayer.interfaces.ITrackUpdates#addTag(int) */ public void addTag(int time) { checkTrackIndexLegal(selectedTrackIndex); this.tracks.get(selectedTrackIndex).addTag(time); } /* * (non-Javadoc) * * @see * edu.chalmers.dat255.audiobookplayer.interfaces.ITrackUpdates#removeTagAt * (int) */ public void removeTagAt(int tagIndex) { checkTrackIndexLegal(selectedTrackIndex); this.tracks.get(selectedTrackIndex).removeTagAt(tagIndex); } /* End ITrackUpdates */ /** * Checks whether a provided index is within the legal bounds of the list of * tracks. * * @param index * Index to check. * @return True if the given index is within bounds of the track list. */ public boolean isLegalTrackIndex(int index) { return index >= 0 && index < tracks.size(); } /** * Returns the number of elements (tracks) in the book. * * @return a Number of elements (tracks). */ public int getNumberOfTracks() { return tracks.size(); } /** * Returns the index of the currently selected track. * * @return int index */ public int getSelectedTrackIndex() { return this.selectedTrackIndex; } /** * The duration of the current track in milliseconds. * * @return */ public int getSelectedTrackDuration() { checkTrackIndexLegal(selectedTrackIndex); return tracks.get(selectedTrackIndex).getDuration(); } /** * Returns the elapsed time of the selected track in the selected book. * * @return elapsed time */ public int getSelectedTrackElapsedTime() { checkTrackIndexLegal(selectedTrackIndex); return this.tracks.get(selectedTrackIndex).getElapsedTime(); } /** * Gets the track path of the currently selected track. * * @return */ public String getSelectedTrackPath() { // TODO: checkTrackLegal... return getTrackPathAt(selectedTrackIndex); } public String getTrackPathAt(int trackIndex) { // TODO: check legal return tracks.get(trackIndex).getTrackPath(); } /** * Returns a list containing references to all tracks contained in this * book. * * @return the list */ public List<String> getTrackPaths() { List<String> paths = new LinkedList<String>(); for (Track t : tracks) { paths.add(t.getTrackPath()); } return paths; } /** * Get a list of all the tracktitles of the book. * * @return The title. */ public List<String> getTrackTitles() { List<String> trackTitles = new LinkedList<String>(); for (Track t : tracks) { trackTitles.add(t.getTrackTitle()); } return trackTitles; } /** * Gets the duration of the book. * * @return duration (ms) */ public int getDuration() { return duration; } /** * Returns the elapsed time of the current book. * * @return The elapsed time of the book. */ public int getBookElapsedTime() { int bookElapsedTime = 0; // add the duration of all previous tracks for (int i = 0; i < this.selectedTrackIndex; i++) { bookElapsedTime += tracks.get(i).getDuration(); } // add the elapsed time of the current track bookElapsedTime += tracks.get(this.selectedTrackIndex).getElapsedTime(); return bookElapsedTime; } /** * Returns the duration (in ms) of the track located at the specified index. * * @param trackIndex * Index of the track * @return int duration (ms) */ public int getTrackDurationAt(int trackIndex) { checkTrackIndexLegal(trackIndex); return tracks.get(trackIndex).getDuration(); } /** * Returns the title of the track. * * @return String title */ public String getTrackTitle() { checkTrackIndexLegal(selectedTrackIndex); return this.tracks.get(selectedTrackIndex).getTrackTitle(); } /* * (non-Javadoc) * * @see java.lang.Object#hashCode() */ @Override public int hashCode() { return new HashCodeBuilder().append(tracks).append(selectedTrackIndex).append(author).append(title) .append(duration).toHashCode(); } /* * (non-Javadoc) * * @see java.lang.Object#equals(java.lang.Object) */ @Override public boolean equals(final Object obj) { if (obj instanceof Book) { final Book other = (Book) obj; return new EqualsBuilder().append(tracks, other.tracks) .append(selectedTrackIndex, other.selectedTrackIndex).append(author, other.author) .append(title, other.title).append(duration, other.duration).isEquals(); } else { return false; } } /** * Returns all tag times. * * @return Array of all tag times. */ public int[] getTagTimes() { checkTrackIndexLegal(selectedTrackIndex); return this.tracks.get(selectedTrackIndex).getTagTimes(); } /* * FOR TESTING PURPOSES ONLY */ /** * Returns a reference to the currently selected track. NOTE: Only for * testing purposes. * * @return the currently selected track */ public Track getSelectedTrack() { return tracks.get(selectedTrackIndex); } /* * END TESTING PURPOSES ONLY */ /** * Gets the track title of a given track index. * * @param trackIndex * Index to get the title from. * @return Track title at given index. */ public String getTrackTitleAt(int trackIndex) { if (trackIndex >= 0 && trackIndex < tracks.size()) { return tracks.get(trackIndex).getTrackTitle(); } return null; } /** * Throws an IndexOutOfBoundsException if the given index is not legal. * * @param trackIndex * The given index. */ private void checkTrackIndexLegal(int trackIndex) { if (!isLegalTrackIndex(trackIndex)) { throw new IndexOutOfBoundsException("Track index is illegal: " + trackIndex); } } }