Resolves issue #23.

Adds audio output display and management options supporting mono and 
stereo output options.

Provides audio output supporting prioritization by talkgroup and/or 
channel selection.

Supports muting all channels, or muting individual channels and
individual audio gain/volume controls.

src/audio/AudioPanel.java

@@ -4,10 +4,21 @@ import java.awt.Color;
 import java.awt.EventQueue;
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
+import java.awt.event.MouseEvent;
+import java.awt.event.MouseListener;
 
-import javax.sound.sampled.BooleanControl;
+import javax.sound.sampled.FloatControl;
+import javax.swing.ImageIcon;
 import javax.swing.JButton;
+import javax.swing.JMenu;
+import javax.swing.JMenuItem;
+import javax.swing.JOptionPane;
 import javax.swing.JPanel;
+import javax.swing.JPopupMenu;
+import javax.swing.JSlider;
+import javax.swing.SwingUtilities;
+import javax.swing.event.ChangeEvent;
+import javax.swing.event.ChangeListener;
 
 import net.miginfocom.swing.MigLayout;
 
@@ -16,68 +27,329 @@ import org.slf4j.LoggerFactory;
 
 import sample.Listener;
 import settings.SettingsManager;
+import source.mixer.MixerChannelConfiguration;
+import source.mixer.MixerManager;
+import audio.output.AudioOutput;
 
 public class AudioPanel extends JPanel implements Listener<AudioEvent>
 {
 	private static final long serialVersionUID = 1L;
 	
 	private static final Logger mLog = LoggerFactory.getLogger( AudioPanel.class );
+	
+	private static ImageIcon MUTED_ICON = SettingsManager.getScaledIcon( 
+			new ImageIcon( "images/audio_muted.png" ), 38 );
+	private static ImageIcon UNMUTED_ICON = SettingsManager.getScaledIcon( 
+			new ImageIcon( "images/audio_unmuted.png" ), 38 );
 
 	private SettingsManager mSettingsManager;
 	private IAudioController mController;
-	private MuteButton mMuteButton;
+
+	private JButton mMuteButton;
+	private AudioChannelsPanel mAudioChannelsPanel;
 	
 	public AudioPanel( SettingsManager settingsManager, IAudioController controller )
 	{
 		mSettingsManager = settingsManager;
 		mController = controller;
 		
-		mMuteButton = new MuteButton( mController );
+		mController.addControllerListener( this );
 		
 		init();
 	}
 	
 	private void init()
 	{
-		setLayout( new MigLayout( "insets 0 0 0 0", "[grow,fill]", "[]0[]") );
+		setLayout( new MigLayout( "insets 0 0 0 0", "[]0[grow,fill]", "[fill]0[]") );
 		setBackground( Color.BLACK );
 
-		add( mMuteButton, "span" );
+		mMuteButton = new MuteButton();
+		mMuteButton.setBackground( getBackground() );
+		add( mMuteButton );
 		
-		for( String channel: mController.getAudioChannels() )
-		{
-			add( new AudioChannelPanel( mSettingsManager, mController, channel ), "span" );
-		}
+		mAudioChannelsPanel = new AudioChannelsPanel( mSettingsManager, mController );
+		
+		add( mAudioChannelsPanel );
+		
+		addMouseListener( new MouseSelectionListener() );
 	}
 	
-	public int getPreferredHeight()
-	{
-		return mMuteButton.getHeight() + 
-			( mController.getAudioChannels().size() * 20 );
-	}
-
 	@Override
 	public void receive( AudioEvent event )
 	{
-		if( event.getType() == AudioEvent.Type.AUDIO_CONFIGURATION_CHANGED )
+		switch( event.getType() )
 		{
-			mLog.debug( "Audio configuration change detected" );
+			case AUDIO_CONFIGURATION_CHANGE_STARTED:
+				break;
+			case AUDIO_CONFIGURATION_CHANGE_COMPLETE:
+				EventQueue.invokeLater( new Runnable()
+				{
+					@Override
+					public void run()
+					{
+						remove( mAudioChannelsPanel );
+
+						mAudioChannelsPanel = new AudioChannelsPanel( 
+								mSettingsManager, mController );
+						
+						add( mAudioChannelsPanel );
+
+						mAudioChannelsPanel.repaint();
+
+						revalidate();
+						repaint();
+					}
+				} );
+				break;
+			default:
+				break;
+		}
+	}
+
+	/**
+	 * Audio output mute control menu item.
+	 */
+	public class AudioOutputMuteItem extends JMenuItem
+	{
+		private static final long serialVersionUID = 1L;
+		
+		private AudioOutput mAudioOutput;
+		
+		public AudioOutputMuteItem( AudioOutput audioOutput )
+		{
+			super( audioOutput.isMuted() ? "Unmute" : "Mute" );
+			
+			mAudioOutput = audioOutput;
+			
+			addActionListener( new ActionListener()
+			{
+				@Override
+				public void actionPerformed( ActionEvent e )
+				{
+					mAudioOutput.setMuted( !mAudioOutput.isMuted() );
+				}
+			} );
 		}
 	}
 	
+	/**
+	 * Mouse listener
+	 */
+	public class MouseSelectionListener implements MouseListener
+	{
+		@Override
+		public void mouseClicked( MouseEvent event )
+		{
+			if( SwingUtilities.isRightMouseButton( event ) )
+			{
+				JPopupMenu popup = new JPopupMenu();
+
+				/* Audio mixer/output selection menus */
+				JMenu outputMenu = new JMenu( "Audio Output" );
+
+				MixerChannelConfiguration[] mixerConfigurations = 
+						MixerManager.getInstance().getOutputMixers();
+
+				for( MixerChannelConfiguration mixerConfig: mixerConfigurations )
+				{
+					MixerSelectionItem mixerItem = new MixerSelectionItem( mixerConfig );
+					
+					try
+					{
+						MixerChannelConfiguration current = mController.getMixerChannelConfiguration();
+
+						if( current != null && current.equals( mixerConfig ) )
+						{
+							mixerItem.setSelected( true );
+						}
+					}
+					catch( AudioException e )
+					{
+						mLog.debug( "Error while detecting current mixer "
+								+ "channel configuration", e );
+					}
+					
+					outputMenu.add( mixerItem );
+				}
+				
+				popup.add( outputMenu );
+
+				/* Audio output mute and volume control */
+				for( AudioOutput output: mController.getAudioOutputs() )
+				{
+					JMenu menu = new JMenu( "Channel: " + output.getChannelName() );
+					
+					menu.add( new AudioOutputMuteItem( output ) );
+					
+					if( output.hasGainControl() )
+					{
+						JMenu volume = new JMenu( "Volume" );
+						volume.add( new VolumeSlider( output.getGainControl() ) );
+						menu.add( volume );
+					}
+					
+					popup.add( menu );
+				}
+				
+				popup.show( event.getComponent(), event.getX(), event.getY() );
+			}
+		}
+
+		@Override
+		public void mousePressed( MouseEvent e ) {}
+		@Override
+		public void mouseReleased( MouseEvent e ) {}
+		@Override
+		public void mouseEntered( MouseEvent e ) {}
+		@Override
+		public void mouseExited( MouseEvent e ) {}
+	}
+	
+	/**
+	 * Audio volume (gain) adjustment slider control
+	 */
+	public class VolumeSlider extends JSlider
+	{
+		private static final long serialVersionUID = 1L;
+		
+		private FloatControl mFloatControl;
+		
+		public VolumeSlider( FloatControl control )
+		{
+			super( 0, 100, 0 );
+			
+	    	setMajorTickSpacing( 25 );
+	    	setMinorTickSpacing( 5 );
+	    	setPaintTicks( true );
+	    	setPaintLabels( true );
+
+			mFloatControl = control;
+			
+			setValue( getIntegerValue( mFloatControl.getValue() ) );
+			
+			addChangeListener( new ChangeListener() 
+			{
+				@Override
+				public void stateChanged( ChangeEvent event )
+				{
+					mFloatControl.shift( mFloatControl.getValue(), 
+						getFloatValue( VolumeSlider.this.getValue() ), 
+						1000 );
+				}
+			} );
+			
+	    	addMouseListener( new MouseListener()
+			{
+				@Override
+				public void mouseClicked( MouseEvent event )
+				{
+					if( event.getClickCount() == 2 )
+					{
+						VolumeSlider.this.setValue( 50 );
+					}
+				}
+				
+				public void mouseReleased( MouseEvent arg0 ) {}
+				public void mousePressed( MouseEvent arg0 ) {}
+				public void mouseExited( MouseEvent arg0 ) {}
+				public void mouseEntered( MouseEvent arg0 ) {}
+			} );
+		}
+
+		/**
+		 * Converts the integer value to a floating point value to use in the
+		 * float control.  Assumes an integer value of 50 is the 0.0 dB mid
+		 * point (ie no gain ) value.
+		 */
+		private int getIntegerValue( float value )
+		{
+			if( value == 0.0f )
+			{
+				return 50;
+			}
+			else if( value < 0.0f )
+			{
+				float ratio = value / mFloatControl.getMinimum();
+				
+				return 50 - (int)( ratio * 50.0f );
+			}
+			else
+			{
+				float ratio = value / mFloatControl.getMaximum();
+				
+				return 50 + (int)( ratio * 50.0f );
+			}
+		}
+		
+		private float getFloatValue( int value )
+		{
+			if( value == 50 )
+			{
+				return 0.0f;
+			}
+			else if( value < 50 )
+			{
+				return (float)( 50 - value ) / 50.0f * mFloatControl.getMinimum();
+			}
+			else
+			{
+				return (float)( value - 50 ) / 50.0f * mFloatControl.getMaximum();
+			}
+		}
+	}
+	
+	/**
+	 * Mixer/Channel configuration selection item
+	 */
+	public class MixerSelectionItem extends JMenuItem
+	{
+		private static final long serialVersionUID = 1L;
+
+		private MixerChannelConfiguration mConfiguration;
+		
+		public MixerSelectionItem( MixerChannelConfiguration config )
+		{
+			super( config.toString() );
+			
+			mConfiguration = config;
+			
+			addActionListener( new ActionListener()
+			{
+				@Override
+				public void actionPerformed( ActionEvent e )
+				{
+					try
+					{
+						mController.setMixerChannelConfiguration( mConfiguration );
+					} 
+					catch ( AudioException e1 )
+					{
+						mLog.error( "Couldn't set mixer channel configuration "
+								+ "to: " + mConfiguration.toString() );
+						
+						JOptionPane.showMessageDialog( MixerSelectionItem.this, 
+							"Couldn't set [" + mConfiguration.toString() + 
+							"] as the audio output device" );
+					}
+				}
+			} );
+		}
+	}
+
+	/**
+	 * Mute button to mute all audio output channels exposed by the audio
+	 * controller
+	 */
 	public class MuteButton extends JButton
 	{
-		private IAudioController mController;
-
+		private static final long serialVersionUID = 1L;
+		
 		private boolean mMuted = false;
 		
-		public MuteButton( IAudioController controller )
+		public MuteButton()
 		{
-			super( "Mute Audio" );
-			
-			setBackground( Color.GREEN );
-			
-			mController = controller;
+			setIcon( UNMUTED_ICON );
+			setBorderPainted( false );
 			
 			addActionListener( new ActionListener()
 			{
@@ -86,31 +358,17 @@ public class AudioPanel extends JPanel implements Listener<AudioEvent>
 				{
 					mMuted = !mMuted;
 					
-					for( String channel: mController.getAudioChannels() )
+					for( AudioOutput output: mController.getAudioOutputs() )
 					{
-						try
-						{
-							BooleanControl control = mController.getMuteControl( channel );
-							
-							if( control != null )
-							{
-								control.setValue( mMuted );
-							}
-						} 
-						catch ( AudioException e1 )
-						{
-							mLog.error( "Couldn't obtain mute control for "
-								+ "channel [" + channel + "] from audio manager", e1 );
-						}
+						output.setMuted( mMuted );
 					}
-
+					
 					EventQueue.invokeLater( new Runnable()
 					{
 						@Override
 						public void run()
 						{
-							MuteButton.this.setText( ( mMuted ? "Unmute Audio" : "Mute Audio" ) );
-							MuteButton.this.setBackground( ( mMuted ? Color.RED : Color.GREEN ) );
+							setIcon( mMuted ? MUTED_ICON : UNMUTED_ICON );
 						}
 					} );
 				}