Implemented seek functionality.

src/main/java/musicplayer/Player.java

@@ -2,6 +2,7 @@ package musicplayer;
 
 import musicplayer.callbacks.PlayerCallbackInterface;
 import musicplayer.model.Song;
+import org.gstreamer.ClockTime;
 import org.gstreamer.ElementFactory;
 import org.gstreamer.Gst;
 import org.gstreamer.State;
@@ -115,7 +116,7 @@ public class Player {
      * @return Current playback position in seconds.
      */
     public int currentSongPosition(){
-        return playBin.isPlaying() || playBin.getState() == State.PAUSED ? (int) (playBin.getClock().getTime().toSeconds() - playBin.getBaseTime().toSeconds()) : 0;
+        return playBin.isPlaying() || playBin.getState() == State.PAUSED ? (int) playBin.queryPosition().toSeconds() : 0;
     }
 
     /**
@@ -134,6 +135,14 @@ public class Player {
         return playBin.getVolumePercent();
     }
 
+    /**
+     * Seek to a position in the song.
+     * @param position Position (in seconds) to seek to.
+     */
+    public void seek(int position){
+        playBin.seek(ClockTime.fromSeconds(position));
+    }
+
     private class InternalThread implements Runnable {
 
         @Override

src/main/java/musicplayer/PlayerGUI.java

@@ -16,10 +16,12 @@ import java.awt.*;
 import java.awt.event.ItemEvent;
 import java.awt.event.MouseAdapter;
 import java.awt.event.MouseEvent;
+import java.awt.event.MouseListener;
 import java.io.File;
 import java.nio.file.Path;
 import java.util.*;
 import java.util.List;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.stream.Collectors;
 
 public class PlayerGUI implements PlayerCallbackInterface, LibraryCallbackInterface {
@@ -32,6 +34,7 @@ public class PlayerGUI implements PlayerCallbackInterface, LibraryCallbackInterf
     private PlaylistTableModel playlistTableModel = new PlaylistTableModel(new ArrayList<>());
     private static DefaultMutableTreeNode updatingNode = new DefaultMutableTreeNode();
     private boolean libraryUpdating = false;
+    private AtomicBoolean seeking = new AtomicBoolean(false);
 
     private Map<String, Runnable> libraryDisplayVariants = createDisplayVariantMap();
 
@@ -69,7 +72,10 @@ public class PlayerGUI implements PlayerCallbackInterface, LibraryCallbackInterf
      * @param position New seekBar value.
      */
     public void setSeekBarPosition(int position) {
-        SwingUtilities.invokeLater(() -> seekBar.setValue(position));
+        SwingUtilities.invokeLater(() -> {
+            if(!seeking.get())
+                seekBar.setValue(position);
+        });
     }
 
     /**
@@ -153,6 +159,9 @@ public class PlayerGUI implements PlayerCallbackInterface, LibraryCallbackInterf
         player.playSong(playlistTableModel.nextSong(player.getCurrentSong()));
     }
 
+    /**
+     * Get the previous song in the playlist and dispatch it to the Player to be played.
+     */
     public void playPreviousSong() {
         SwingUtilities.invokeLater(() -> seekBar.setValue(0));
         player.playSong(playlistTableModel.previous(player.getCurrentSong()));
@@ -222,6 +231,9 @@ public class PlayerGUI implements PlayerCallbackInterface, LibraryCallbackInterf
         ((DefaultTreeModel)libraryView.getModel()).nodeChanged(updatingNode);
     }
 
+    /**
+     * @return Map of display types for the library paired code to populate the library with data in the correct format.
+     */
     private Map<String, Runnable> createDisplayVariantMap() {
         Map<String, Runnable> value = new HashMap<>();
         value.put("Song", () -> Gateway.listAllSongs().ifPresent(this::populateLibrary));
@@ -272,11 +284,15 @@ public class PlayerGUI implements PlayerCallbackInterface, LibraryCallbackInterf
         seekBar = new JSlider();
         seekBar.setMinorTickSpacing(1);
         seekBar.setValue(0);
+        seekBar.addMouseListener(new SeekbarMouseListener());
         controlPane.add(seekBar, BorderLayout.NORTH);
         controlPane.add(createControlButtons(), BorderLayout.SOUTH);
         mainPanel.add(createMenuBar(), BorderLayout.NORTH);
     }
 
+    /**
+     * @return Area containing the library.
+     */
     private JTree createLibraryArea() {
         libraryView.setRootVisible(false);
         libraryView.setToggleClickCount(1);
@@ -285,6 +301,9 @@ public class PlayerGUI implements PlayerCallbackInterface, LibraryCallbackInterf
         return libraryView;
     }
 
+    /**
+     * @return Area containing the playlist.
+     */
     private JScrollPane createPlaylistArea() {
         JScrollPane playlistScroll = new JScrollPane();
         playList.setRowSelectionAllowed(true);
@@ -308,6 +327,9 @@ public class PlayerGUI implements PlayerCallbackInterface, LibraryCallbackInterf
         return playlistScroll;
     }
 
+    /**
+     * @return Playback control buttons (play, stop, etc.)
+     */
     private JToolBar createControlButtons() {
         JToolBar toolBar = new JToolBar();
         toolBar.setFloatable(false);
@@ -345,6 +367,9 @@ public class PlayerGUI implements PlayerCallbackInterface, LibraryCallbackInterf
         return toolBar;
     }
 
+    /**
+     * @return Volume controls.
+     */
     private JPanel createVolumeControls() {
         JPanel panel = new JPanel();
         panel.setLayout(new FlowLayout());
@@ -410,4 +435,29 @@ public class PlayerGUI implements PlayerCallbackInterface, LibraryCallbackInterf
             }
         }
     }
+
+    /**
+     * MouseListener implementation for the seekbar.
+     * Using this instead of the ChangeListener so that the polling for the current song position
+     * doesn't repeatedly fire seek events.
+     */
+    private class SeekbarMouseListener implements MouseListener {
+        @Override
+        public void mouseClicked(MouseEvent e) { seeking.set(true); }
+
+        @Override
+        public void mousePressed(MouseEvent e) { seeking.set(true); }
+
+        @Override
+        public void mouseReleased(MouseEvent e) {
+            player.seek(seekBar.getValue());
+            seeking.set(false);
+        }
+
+        @Override
+        public void mouseEntered(MouseEvent e) {}
+
+        @Override
+        public void mouseExited(MouseEvent e) {}
+    }
 }

src/main/java/musicplayer/callbacks/LibraryCallbackInterface.java

@@ -2,7 +2,15 @@ package musicplayer.callbacks;
 
 public interface LibraryCallbackInterface {
 
+    /**
+     * Call this after performing library updates so the front-end knows that updating has completed.
+     * @param successful Was the update function successful.
+     */
     void libraryUpdated(boolean successful);
 
+    /**
+     * Update the current display with the file/folder currently being parsed.
+     * @param name Data about the file/folder to be shown to the user.
+     */
     void currentlyUpdating(String name);
 }

src/main/java/musicplayer/callbacks/PlayerCallbackInterface.java

@@ -6,14 +6,32 @@ import java.util.Optional;
 
 public interface PlayerCallbackInterface {
 
+    /**
+     * Set the song currently shown to the user as playing.
+     * @param playingSong Song currently playing.
+     */
     void setSongHighlighting(Song playingSong);
 
+    /**
+     * Set the seekbar position.
+     * @param seconds Position to set the seekbar to.
+     */
     void setSeekBarDuration(int seconds);
 
+    /**
+     * Remove a song from the current playlist.
+     * @param invalidSong Song to remove.
+     */
     void removeInvalidSong(Song invalidSong);
 
+    /**
+     * Playback has ceased.
+     */
     void playerStopped();
 
+    /**
+     * Start playing the next song.
+     */
     void playNextSong();
 
 }