Added additional playback controls.

src/main/java/musicplayer/Player.java

@@ -51,8 +51,12 @@ public class Player {
     public void playSong(Optional<Song> inputSong){
         if (playBin.getState() == State.PLAYING)
             stop();
-        playBin.setState(State.READY);
         if(inputSong.isPresent()) {
+            if(playBin.getState() == State.PAUSED && inputSong.get() == currentSong) {
+                resume();
+                return;
+            }
+            playBin.setState(State.READY);
             currentSong = inputSong.get();
             callbackInterface.setSongHighlighting(currentSong);
             File songFile = currentSong.getSongFile();
@@ -111,7 +115,7 @@ public class Player {
      * @return Current playback position in seconds.
      */
     public int currentSongPosition(){
-        return playBin.isPlaying() ? (int) (playBin.getClock().getTime().toSeconds() - playBin.getBaseTime().toSeconds()) : 0;
+        return playBin.isPlaying() || playBin.getState() == State.PAUSED ? (int) (playBin.getClock().getTime().toSeconds() - playBin.getBaseTime().toSeconds()) : 0;
     }
 
     /**

src/main/java/musicplayer/PlayerGUI.java

@@ -156,6 +156,11 @@ public class PlayerGUI implements PlayerCallbackInterface, LibraryCallbackInterf
         player.playSong(playlistTableModel.nextSong(player.getCurrentSong()));
     }
 
+    public void playPreviousSong() {
+        SwingUtilities.invokeLater(() -> seekBar.setValue(0));
+        player.playSong(playlistTableModel.previous(player.getCurrentSong()));
+    }
+
     /**
      * Set the maximum value of the seekBar.
      *
@@ -285,8 +290,8 @@ public class PlayerGUI implements PlayerCallbackInterface, LibraryCallbackInterf
         playList.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
         playList.getColumnModel().getColumn(0).setPreferredWidth(10);
         playList.getColumnModel().getColumn(0).setMaxWidth(10);
-        playList.getColumnModel().getColumn(1).setPreferredWidth(30);
+        playList.getColumnModel().getColumn(1).setPreferredWidth(40);
-        playList.getColumnModel().getColumn(1).setMaxWidth(30);
+        playList.getColumnModel().getColumn(1).setMaxWidth(40);
         JPopupMenu popupMenu = new JPopupMenu();
         JMenuItem menuItem = new JMenuItem("Remove");
         menuItem.addActionListener((e) -> playlistTableModel.removeSong(playList.getSelectedRows()));
@@ -304,8 +309,7 @@ public class PlayerGUI implements PlayerCallbackInterface, LibraryCallbackInterf
     private JToolBar createControlButtons() {
         JToolBar toolBar = new JToolBar();
         toolBar.setFloatable(false);
-        JButton playButton = new JButton();
+        JButton playButton = new JButton("Play");
-        playButton.setText("Play");
         playButton.setMnemonic('P');
         playButton.setDisplayedMnemonicIndex(0);
         playButton.addActionListener(e -> {
@@ -317,14 +321,20 @@ public class PlayerGUI implements PlayerCallbackInterface, LibraryCallbackInterf
             }
         });
         toolBar.add(playButton);
-        JButton stopButton = new JButton();
+        JButton pauseButton = new JButton("Pause");
-        stopButton.setText("Stop");
+        pauseButton.setMnemonic('E');
+        pauseButton.addActionListener(e -> player.pause());
+        toolBar.add(pauseButton);
+        JButton stopButton = new JButton("Stop");
         stopButton.setMnemonic('S');
         stopButton.setDisplayedMnemonicIndex(0);
         stopButton.addActionListener(e -> player.stop());
         toolBar.add(stopButton);
-        JButton nextButton = new JButton();
+        JButton previousButton = new JButton("Previous");
-        nextButton.setText("Next");
+        previousButton.setMnemonic('R');
+        previousButton.addActionListener(e -> playPreviousSong());
+        toolBar.add(previousButton);
+        JButton nextButton = new JButton("Next");
         nextButton.setMnemonic('N');
         nextButton.setDisplayedMnemonicIndex(0);
         nextButton.addActionListener(e -> playNextSong());

src/main/java/musicplayer/swingmodels/PlaylistTableModel.java

@@ -23,7 +23,7 @@ public class PlaylistTableModel extends AbstractTableModel {
 
     @Override
     public int getColumnCount() {
-        return 6;
+        return 5;
     }
 
     @Override
@@ -36,7 +36,6 @@ public class PlaylistTableModel extends AbstractTableModel {
             case 2: o = song.getTitle(); break;
             case 3: o = song.getArtist(); break;
             case 4: o = song.getAlbum(); break;
-            case 5: o = song.getDiscNumber(); break;
         }
         return o;
     }
@@ -55,7 +54,6 @@ public class PlaylistTableModel extends AbstractTableModel {
             case 2: name = "Title"; break;
             case 3: name = "Artist"; break;
             case 4: name = "Album"; break;
-            case 5: name = "DiscNo"; break;
         }
         return name;
     }
@@ -75,10 +73,10 @@ public class PlaylistTableModel extends AbstractTableModel {
         return songList.size() > 0 ? Optional.of(songList.get(index)) : Optional.empty();
     }
 
-    public Song previous(Song song){
+    public Optional<Song> previous(Song song){
         int index = songList.indexOf(song) - 1;
         if(index < 0) index = songList.size() - 1;
-        return songList.get(index);
+        return songList.size() > 0 ? Optional.of(songList.get(index)) : Optional.empty();
     }
 
     public int getSongIndex(Song song){