view/fantasia/Channel.java

/*
 *   JSampler - a java front-end for LinuxSampler
 *
 *   Copyright (C) 2005-2006 Grigor Iliev <grigor@grigoriliev.com>
 *
 *   This file is part of JSampler.
 *
 *   JSampler is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License version 2
 *   as published by the Free Software Foundation.
 *
 *   JSampler is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with JSampler; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 *   MA  02111-1307  USA
 */

package org.jsampler.view.fantasia;

import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.Insets;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import java.util.logging.Level;

import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.DefaultListCellRenderer;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JToggleButton;
import javax.swing.SwingConstants;

import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

import net.sf.juife.Dial;
import net.sf.juife.JuifeUtils;
import net.sf.juife.TitleBar;

import org.jsampler.AudioDeviceModel;
import org.jsampler.CC;
import org.jsampler.MidiDeviceModel;
import org.jsampler.SamplerChannelModel;
import org.jsampler.SamplerModel;

import org.jsampler.event.ListEvent;
import org.jsampler.event.ListListener;
import org.jsampler.event.MidiDeviceListEvent;
import org.jsampler.event.MidiDeviceListListener;
import org.jsampler.event.SamplerChannelAdapter;
import org.jsampler.event.SamplerChannelEvent;
import org.jsampler.event.SamplerChannelListener;

import org.linuxsampler.lscp.AudioOutputDevice;
import org.linuxsampler.lscp.MidiInputDevice;
import org.linuxsampler.lscp.MidiPort;
import org.linuxsampler.lscp.SamplerChannel;
import org.linuxsampler.lscp.SamplerEngine;

import static org.jsampler.view.fantasia.FantasiaI18n.i18n;


/**
 *
 * @author Grigor Iliev
 */
public class Channel extends org.jsampler.view.JSChannel {
        private final ChannelScreen screen = new ChannelScreen(this);
        private final ChannelOptions optionsPane = new ChannelOptions(this);
        
        private final PowerButton btnPower = new PowerButton();
        private final MuteButton btnMute = new MuteButton();
        private final SoloButton btnSolo = new SoloButton();
        private final OptionsButton btnOptions = new OptionsButton();
        
        private final EnhancedDial dialVolume = new EnhancedDial();
        
        private boolean selected = false;
        
        /**
         * Creates a new instance of <code>Channel</code> using the specified
         * non-<code>null</code> channel model.
         * @param model The model to be used by this channel.
         * @throws IllegalArgumentException If the model is <code>null</code>.
         */
        public
        Channel(SamplerChannelModel model) {
                super(model);
                
                setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
                JPanel p = new JPanel();
                p.setName("Channel");
                p.setLayout(new BoxLayout(p, BoxLayout.X_AXIS));
                
                //p.add(Box.createRigidArea(new Dimension(3, 0)));
                
                btnPower.setAlignmentY(JPanel.TOP_ALIGNMENT);
                
                TitleBar tb = new TitleBar();
                tb.setBorder(BorderFactory.createEmptyBorder(3, 3, 0, 4));
                tb.setLayout(new BoxLayout(tb, BoxLayout.X_AXIS));
                tb.setOpaque(false);
                tb.setAlignmentY(JPanel.TOP_ALIGNMENT);
                tb.add(btnPower);
                tb.setPreferredSize(new Dimension(tb.getPreferredSize().width, 58));
                tb.setMinimumSize(tb.getPreferredSize());
                tb.setMaximumSize(tb.getPreferredSize());
                p.add(tb);
                
                //p.add(Box.createRigidArea(new Dimension(4, 0)));
                
                p.add(createVSeparator());
                
                //p.add(Box.createRigidArea(new Dimension(3, 0)));
                
                JPanel p2 = new JPanel();
                p2.setOpaque(false);
                p2.setLayout(new BoxLayout(p2, BoxLayout.Y_AXIS));
                p2.setAlignmentY(JPanel.TOP_ALIGNMENT);
                p2.setBorder(BorderFactory.createEmptyBorder(5, 3, 0, 2));
                p2.add(screen);
                p.add(p2);
                
                p.add(createVSeparator());
                
                p2 = new JPanel();
                p2.setOpaque(false);
                p2.setLayout(new BoxLayout(p2, BoxLayout.Y_AXIS));
                p2.setAlignmentY(JPanel.TOP_ALIGNMENT);
                p2.setBorder(BorderFactory.createEmptyBorder(4, 0, 0, 0));
                p2.add(new JLabel(Res.iconMuteTitle));
                p2.add(btnMute);
                p2.add(new JLabel(Res.iconSoloTitle));
                p2.add(btnSolo);
                
                p.add(p2);
                
                p.add(createVSeparator());
                
                p2 = new JPanel();
                p2.setOpaque(false);
                p2.setLayout(new BoxLayout(p2, BoxLayout.Y_AXIS));
                p2.setAlignmentY(JPanel.TOP_ALIGNMENT);
                p2.setBorder(BorderFactory.createEmptyBorder(4, 0, 0, 0));
                JLabel l = new JLabel(Res.iconVolumeTitle);
                l.setAlignmentX(JPanel.CENTER_ALIGNMENT);
                l.setBorder(BorderFactory.createEmptyBorder(0, 0, 2, 0));
                p2.add(l);
                dialVolume.setDialPixmap(Res.iconVolumeDial, 30, 330);
                dialVolume.setAlignmentX(JPanel.CENTER_ALIGNMENT);
                p2.add(dialVolume);
                p.add(p2);
                
                p.add(createVSeparator());
                
                p2 = new JPanel();
                p2.setOpaque(false);
                p2.setLayout(new BoxLayout(p2, BoxLayout.Y_AXIS));
                p2.setAlignmentY(JPanel.TOP_ALIGNMENT);
                p2.setBorder(BorderFactory.createEmptyBorder(27, 0, 0, 0));
                l = new JLabel(Res.iconOptionsTitle);
                l.setAlignmentX(JPanel.CENTER_ALIGNMENT);
                l.setBorder(BorderFactory.createEmptyBorder(0, 0, 2, 0));
                p2.add(l);
                
                p2.add(Box.createRigidArea(new Dimension(0, 3)));
                
                btnOptions.setAlignmentX(JPanel.CENTER_ALIGNMENT);
                p2.add(btnOptions);
                p.add(p2);
                
                
                p.setPreferredSize(new Dimension(420, 60));
                p.setMinimumSize(p.getPreferredSize());
                p.setMaximumSize(p.getPreferredSize());
                //p.setBorder(BorderFactory.createEmptyBorder(1, 0, 1, 0));

                p.setAlignmentX(JPanel.CENTER_ALIGNMENT);
                optionsPane.setAlignmentX(JPanel.CENTER_ALIGNMENT);
                add(p);
                add(optionsPane);
                
                setOpaque(true);
                
                getModel().addSamplerChannelListener(getHandler());
                
                updateChannelInfo();
        }
        
        private JPanel
        createVSeparator() {
                JPanel p = new JPanel();
                p.setName("VSeparator");
                p.setOpaque(false);
                p.setAlignmentY(JPanel.TOP_ALIGNMENT);
                p.setPreferredSize(new Dimension(2, 60));
                p.setMinimumSize(p.getPreferredSize());
                p.setMaximumSize(p.getPreferredSize());
                return p;
        }
        
        /**
         * Determines whether the channel is selected.
         * @return <code>true</code> if the channel is selected, <code>false</code> otherwise.
         */
        public boolean isSelected() { return selected; }
        
        /**
         * Sets the selection state of this channel.
         * This method is invoked when the selection state of the channel has changed.
         * @param select Specifies the new selection state of this channel;
         * <code>true</code> to select the channel, <code>false</code> otherwise.
         */
        public void
        setSelected(boolean select) {
                
                selected = select;
        }
        
        /** Shows the channel properties. */
        public void
        expandChannel() { if(!btnOptions.isSelected()) btnOptions.doClick(); }
        
        
        /** Invoked when the user changes the volume */
        private void
        setVolume() {
                screen.updateVolumeInfo(dialVolume.getValue());
                
                if(dialVolume.getValueIsAdjusting()) return;
                
                int vol = (int)(getChannelInfo().getVolume() * 100);
                
                if(vol == dialVolume.getValue()) return;
                
                
                /*
                 * If the model's volume is not equal to the dial knob
                 * value we assume that the change is due to user input.
                 * So we must update the volume at the backend too.
                 */
                float volume = dialVolume.getValue();
                volume /= 100;
                getModel().setBackendVolume(volume);
        }
        
        /**
         * Updates the channel settings. This method is invoked when changes to the
         * channel were made.
         */
        private void
        updateChannelInfo() {
                SamplerChannel sc = getChannelInfo();
                
                screen.updateScreenInfo(sc);
                updateMuteIcon(sc);
                
                if(sc.isSoloChannel()) btnSolo.setIcon(Res.iconSoloOn);
                else btnSolo.setIcon(Res.iconSoloOff);
                
                dialVolume.setValue((int)(sc.getVolume() * 100));
                
                boolean b = sc.getEngine() != null;
                dialVolume.setEnabled(b);
                btnSolo.setEnabled(b);
                btnMute.setEnabled(b);
        }
        
        /**
         * Updates the mute button with the proper icon regarding to information obtained
         * from <code>channel</code>.
         * @param channel A <code>SamplerChannel</code> instance containing the new settings
         * for this channel.
         */
        private void
        updateMuteIcon(SamplerChannel channel) {
                if(channel.isMutedBySolo()) btnMute.setIcon(Res.iconMutedBySolo);
                else if(channel.isMuted()) btnMute.setIcon(Res.iconMuteOn);
                else btnMute.setIcon(Res.iconMuteOff);
        }
        
        private class EnhancedDial extends Dial {
                EnhancedDial() {
                        super(0, 100);
                        
                        setMouseHandlerMode(MouseHandlerMode.LEFT_TO_RIGHT_AND_DOWN_TO_UP);
                        
                        addMouseListener(new MouseAdapter() {
                                public void
                                mouseClicked(MouseEvent e) {
                                        if(e.getButton() == e.BUTTON3) {
                                                setValue(getMaximum() / 2);
                                                return;
                                        }
                                        
                                        if(e.getButton() != e.BUTTON1) return;
                                        
                                        if(e.getClickCount() < 2) return;
                                        setValue(getValueByPoint(e.getPoint()));
                                }
                        });
                        
                        addChangeListener(new ChangeListener() {
                                public void
                                stateChanged(ChangeEvent e) { setVolume(); }
                        });
                }
        }
        
        private final EventHandler eventHandler = new EventHandler();
        
        private EventHandler
        getHandler() { return eventHandler; }
        
        private class EventHandler implements SamplerChannelListener {
                /**
                 * Invoked when changes are made to a sampler channel.
                 * @param e A <code>SamplerChannelEvent</code> instance
                 * containing event information.
                 */
                public void
                channelChanged(SamplerChannelEvent e) { updateChannelInfo(); }
        
                /**
                 * Invoked when the number of active disk streams has changed.
                 * @param e A <code>SamplerChannelEvent</code> instance
                 * containing event information.
                 */
                public void
                streamCountChanged(SamplerChannelEvent e) {
                        screen.updateStreamCount(getModel().getStreamCount());
                }
        
                /**
                 * Invoked when the number of active voices has changed.
                 * @param e A <code>SamplerChannelEvent</code> instance
                 * containing event information.
                 */
                public void
                voiceCountChanged(SamplerChannelEvent e) {
                        screen.updateVoiceCount(getModel().getVoiceCount());
                }
        }
        
        
        private class PowerButton extends PixmapToggleButton implements ActionListener {
                PowerButton() {
                        super(Res.iconPowerOff, Res.iconPowerOn);
                
                        setSelected(true);
                        addActionListener(this);
                }
                
                public void
                actionPerformed(ActionEvent e) {
                        CC.getSamplerModel().removeBackendChannel(getChannelId());
                }
                
                public boolean
                contains(int x, int y) { return (x - 11)*(x - 11) + (y - 11)*(y - 11) < 71; }
        }
        
        private class MuteButton extends PixmapButton implements ActionListener {
                MuteButton() {
                        super(Res.iconMuteOff);
                        setDisabledIcon(Res.iconMuteSoloDisabled);
                        addActionListener(this);
                }
                
                public void
                actionPerformed(ActionEvent e) {
                        SamplerChannel sc = getChannelInfo();
                        boolean b = true;
                
                        /*
                         * Changing the mute button icon now instead of
                         * leaving the work to the notification mechanism of the LinuxSampler.
                         */
                        if(sc.isMuted() && !sc.isMutedBySolo()) {
                                b = false;
                                boolean hasSolo = CC.getSamplerModel().hasSoloChannel();
                        
                                if(sc.isSoloChannel() || !hasSolo) setIcon(Res.iconMuteOff);
                                else setIcon(Res.iconMutedBySolo);
                        } else setIcon(Res.iconMuteOn);
                        
                        Channel.this.getModel().setBackendMute(b);
                }
                
                public boolean
                contains(int x, int y) { return (x > 5 && x < 23) && (y > 5 && y < 16); }
        }
        
        private class SoloButton extends PixmapButton implements ActionListener {
                SoloButton() {
                        super(Res.iconSoloOff);
                        setDisabledIcon(Res.iconMuteSoloDisabled);
                        addActionListener(this);
                }
                
                public void
                actionPerformed(ActionEvent e) {
                        SamplerChannel sc = getChannelInfo();
                        boolean b = !sc.isSoloChannel();
                
                        /*
                         * Changing the solo button icon (and related) now instead of
                         * leaving the work to the notification mechanism of the LinuxSampler.
                         */
                        if(b) {
                                setIcon(Res.iconSoloOn);
                                if(sc.isMutedBySolo()) btnMute.setIcon(Res.iconMuteOff);
                        } else {
                                setIcon(Res.iconSoloOff);
                                if(!sc.isMuted() && CC.getSamplerModel().getSoloChannelCount() > 1)
                                        btnMute.setIcon(Res.iconMutedBySolo);
                        }
                
                        Channel.this.getModel().setBackendSolo(b);
                }
                
                public boolean
                contains(int x, int y) { return (x > 5 && x < 23) && (y > 5 && y < 16); }
        }
        
        private class OptionsButton extends PixmapToggleButton implements ActionListener {
                OptionsButton() {
                        super(Res.iconOptionsOff, Res.iconOptionsOn);
                        setRolloverIcon(Res.iconOptionsOffRO);
                        this.setRolloverSelectedIcon(Res.iconOptionsOnRO);
                        addActionListener(this);
                }
                
                public void
                actionPerformed(ActionEvent e) {
                        showOptionsPane(isSelected());
                        
                        String s;
                        if(isSelected()) s = i18n.getButtonLabel("OptionsButton.ttHideOptions");
                        else s = i18n.getButtonLabel("OptionsButton.ttShowOptions");
                        
                        setToolTipText(s);
                }
                
                private void
                showOptionsPane(boolean show) {
                        optionsPane.setVisible(show);
                        MainFrame.repack(CC.getMainFrame());
                }
                
                public boolean
                contains(int x, int y) { return super.contains(x, y) & y < 13; }
        }
}

class ChannelScreen extends JPanel {
        private final Channel channel;
        private JButton btnInstr = new ScreenButton(i18n.getButtonLabel("ChannelScreen.btnInstr"));
        private JButton btnReset = new ScreenButton(i18n.getButtonLabel("ChannelScreen.btnReset"));
        private JButton btnDuplicate =
                new ScreenButton(i18n.getButtonLabel("ChannelScreen.btnDuplicate"));
        
        private final JLabel lVolume = new JLabel();
        private final JLabel lStreams = new JLabel("--");
        private final JLabel lVoices = new JLabel("--");
        
        ChannelScreen(Channel channel) {
                this.channel = channel;
                
                setName("ChannelScreen");
                setOpaque(true);
                
                setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
                
                btnInstr.setBorder(BorderFactory.createEmptyBorder(10, 0, 0, 0));
                btnInstr.setAlignmentX(CENTER_ALIGNMENT);
                
                add(btnInstr);
                
                JPanel p = new JPanel();
                p.setOpaque(false);
                p.setLayout(new BoxLayout(p, BoxLayout.X_AXIS));
                p.setAlignmentX(CENTER_ALIGNMENT);
                p.setBorder(BorderFactory.createEmptyBorder(10, 0, 0, 0));
                //lVolume.setFont(lVolume.getFont().deriveFont(java.awt.Font.PLAIN));
                
                p.add(btnDuplicate);
                
                p.add(Box.createRigidArea(new Dimension(6, 0)));
                
                p.add(new JLabel("|"));
                
                p.add(Box.createRigidArea(new Dimension(6, 0)));
                
                p.add(btnReset);
                
                p.add(Box.createGlue());
                
                p.add(lStreams);
                p.add(new JLabel("/"));
                p.add(lVoices);
                
                p.add(Box.createRigidArea(new Dimension(12, 0)));
                
                lVolume.setAlignmentX(RIGHT_ALIGNMENT);
                p.add(lVolume);
                p.setPreferredSize(new Dimension(250, p.getPreferredSize().height));
                p.setMinimumSize(p.getPreferredSize());
                p.setMaximumSize(p.getPreferredSize());
                
                add(p);
                
                
                setPreferredSize(new Dimension(270, 48));
                setMinimumSize(getPreferredSize());
                setMaximumSize(getPreferredSize());
                
                installListeners();
        }
        
        private void
        installListeners() {
                btnInstr.addActionListener(new ActionListener() {
                        public void
                        actionPerformed(ActionEvent e) { loadInstrument(); }
                });
        
                btnReset.addActionListener(new ActionListener() {
                        public void
                        actionPerformed(ActionEvent e) { channel.getModel().resetBackendChannel(); }
                });
                
                btnDuplicate.addActionListener(new ActionListener() {
                        public void
                        actionPerformed(ActionEvent e) {
                                channel.getModel().duplicateBackendChannel();
                        }
                });
        }

        private void
        loadInstrument() {
                InstrumentChooser dlg = new InstrumentChooser(CC.getMainFrame());
                dlg.setVisible(true);
                
                if(!dlg.isCancelled()) {
                        SamplerChannelModel m = channel.getModel();
                        m.loadBackendInstrument(dlg.getFileName(), dlg.getInstrumentIndex());
                }
        }
        
        protected void
        updateScreenInfo(SamplerChannel sc) {
                int status = sc.getInstrumentStatus();
                if(status >= 0 && status < 100) {
                        btnInstr.setText(i18n.getLabel("ChannelScreen.loadingInstrument", status));
                } else if(status == -1) {
                        btnInstr.setText(i18n.getButtonLabel("ChannelScreen.btnInstr"));
                } else if(status < -1) {
                         btnInstr.setText(i18n.getLabel("ChannelScreen.errorLoadingInstrument"));
                } else {
                        if(sc.getInstrumentName() != null) btnInstr.setText(sc.getInstrumentName());
                        else btnInstr.setText(i18n.getButtonLabel("ChannelScreen.btnInstr"));
                }
        
                
        }
        
        protected void
        updateVolumeInfo(int volume) {
                lVolume.setText(i18n.getLabel("ChannelScreen.volume", volume));
                
        }
        
        /**
         * Updates the number of active disk streams.
         * @param count The new number of active disk streams.
         */
        protected void
        updateStreamCount(int count) {
                Dimension d = lStreams.getPreferredSize();
                lStreams.setText(count == 0 ? "--" : String.valueOf(count));
                d = JuifeUtils.getUnionSize(d, lStreams.getPreferredSize());
                lStreams.setMinimumSize(d);
                lStreams.setPreferredSize(d);
                lStreams.setMaximumSize(d);
        }
        
        /**
         * Updates the number of active voices.
         * @param count The new number of active voices.
         */
        protected void
        updateVoiceCount(int count) {
                Dimension d = lVoices.getPreferredSize();
                lVoices.setText(count == 0 ? "--" : String.valueOf(count));
                d = JuifeUtils.getUnionSize(d, lVoices.getPreferredSize());
                lVoices.setMinimumSize(d);
                lVoices.setPreferredSize(d);
                lVoices.setMaximumSize(d);
        }
        
        static class ScreenButton extends JButton {
                ScreenButton(String s) {
                        super(s);
                        setContentAreaFilled(false);
                        setFocusPainted(false);
                        setBorder(BorderFactory.createEmptyBorder(0, 0, 0, 0));
                        setMargin(new Insets(0, 0, 0, 0));
                        setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
                }
        }
}

class ChannelOptions extends JPanel {
        private final Channel channel;
        
        private final JComboBox cbMidiDevice = new JComboBox();
        private final JComboBox cbMidiPort = new JComboBox();
        private final JComboBox cbMidiChannel = new JComboBox();
        private final JComboBox cbEngine = new JComboBox();
        private final JComboBox cbAudioDevice = new JComboBox();
        
        private boolean update = false;
        
        ChannelOptions(Channel channel) {
                this.channel = channel;
                
                setName("ChannelOptions");
                setVisible(false);
                setBorder(BorderFactory.createEmptyBorder(5, 4, 5, 4));
                setLayout(new BoxLayout(this, BoxLayout.X_AXIS));
                
                setPreferredSize(new Dimension(420, 44));
                setMinimumSize(getPreferredSize());
                setMaximumSize(getPreferredSize());
                
                JPanel p = new JPanel();
                p.setOpaque(true);
                p.setBorder(BorderFactory.createEmptyBorder(3, 4, 3, 4));
                p.setLayout(new BoxLayout(p, BoxLayout.Y_AXIS));
                JLabel l = new JLabel(Res.iconMidiInputTitle);
                l.setAlignmentX(LEFT_ALIGNMENT);
                p.add(l);
                
                JPanel p2 = new JPanel();
                p2.setBorder(BorderFactory.createEmptyBorder(3, 0, 0, 0));
                p2.setLayout(new BoxLayout(p2, BoxLayout.X_AXIS));
                
                Object o = cbMidiDevice.getRenderer();
                if(o instanceof JLabel) ((JLabel )o).setHorizontalAlignment(SwingConstants.CENTER);
                
                cbMidiDevice.setPreferredSize(new Dimension(40, 18));
                cbMidiDevice.setMinimumSize(cbMidiDevice.getPreferredSize());
                cbMidiDevice.setMaximumSize(cbMidiDevice.getPreferredSize());
                p2.add(cbMidiDevice);
                
                p2.add(Box.createRigidArea(new Dimension(3, 0)));
                
                o = cbMidiPort.getRenderer();
                if(o instanceof JLabel) ((JLabel )o).setHorizontalAlignment(SwingConstants.CENTER);
                
                cbMidiPort.setPreferredSize(new Dimension(67, 18));
                cbMidiPort.setMinimumSize(cbMidiPort.getPreferredSize());
                cbMidiPort.setMaximumSize(cbMidiPort.getPreferredSize());
                p2.add(cbMidiPort);
                
                p2.add(Box.createRigidArea(new Dimension(3, 0)));
                
                o = cbMidiChannel.getRenderer();
                if(o instanceof JLabel) ((JLabel )o).setHorizontalAlignment(SwingConstants.CENTER);
                
                cbMidiChannel.addItem("All");
                for(int i = 1; i <= 16; i++) cbMidiChannel.addItem("Channel " + String.valueOf(i));
                cbMidiChannel.setPreferredSize(new Dimension(80, 18));
                cbMidiChannel.setMinimumSize(cbMidiChannel.getPreferredSize());
                cbMidiChannel.setMaximumSize(cbMidiChannel.getPreferredSize());
                
                p2.add(cbMidiChannel);
                p2.setAlignmentX(LEFT_ALIGNMENT);
                p.add(p2);
                
                add(p);
                
                add(Box.createRigidArea(new Dimension(4, 0)));
                
                p = new JPanel();
                p.setOpaque(true);
                p.setBorder(BorderFactory.createEmptyBorder(3, 4, 3, 4));
                p.setLayout(new BoxLayout(p, BoxLayout.Y_AXIS));
                l = new JLabel(Res.iconEngineTitle);
                l.setAlignmentX(LEFT_ALIGNMENT);
                l.setAlignmentX(LEFT_ALIGNMENT);
                p.add(l);
                
                p.add(Box.createRigidArea(new Dimension(0, 3)));
                
                o = cbEngine.getRenderer();
                if(o instanceof JLabel) ((JLabel )o).setHorizontalAlignment(SwingConstants.CENTER);
                
                for(SamplerEngine e : CC.getSamplerModel().getEngines()) cbEngine.addItem(e);
                cbEngine.setPreferredSize(new Dimension(125, 18));
                cbEngine.setMinimumSize(cbEngine.getPreferredSize());
                cbEngine.setMaximumSize(cbEngine.getPreferredSize());
                cbEngine.setAlignmentX(LEFT_ALIGNMENT);
                p.add(cbEngine);
                
                add(p);
                
                add(Box.createRigidArea(new Dimension(4, 0)));
                
                p = new JPanel();
                p.setOpaque(true);
                p.setBorder(BorderFactory.createEmptyBorder(3, 4, 3, 4));
                p.setLayout(new BoxLayout(p, BoxLayout.Y_AXIS));
                l = new JLabel(Res.iconAudioOutputTitle);
                l.setAlignmentX(LEFT_ALIGNMENT);
                l.setAlignmentX(LEFT_ALIGNMENT);
                p.add(l);
                
                p.add(Box.createRigidArea(new Dimension(0, 3)));
                
                o = cbAudioDevice.getRenderer();
                if(o instanceof JLabel) ((JLabel )o).setHorizontalAlignment(SwingConstants.RIGHT);
                
                cbAudioDevice.setPreferredSize(new Dimension(61, 18));
                cbAudioDevice.setMinimumSize(cbAudioDevice.getPreferredSize());
                cbAudioDevice.setMaximumSize(cbAudioDevice.getPreferredSize());
                cbAudioDevice.setAlignmentX(LEFT_ALIGNMENT);
                p.add(cbAudioDevice);
                
                add(p);
                
                cbMidiDevice.addActionListener(new ActionListener() {
                        public void
                        actionPerformed(ActionEvent e) { setMidiDevice(); }
                });
                
                cbMidiPort.addActionListener(new ActionListener() {
                        public void
                        actionPerformed(ActionEvent e) { setMidiPort(); }
                });
                
                cbMidiChannel.addActionListener(new ActionListener() {
                        public void
                        actionPerformed(ActionEvent e) { setMidiChannel(); }
                });
                
                cbEngine.addActionListener(new ActionListener() {
                        public void
                        actionPerformed(ActionEvent e) { setEngineType(); }
                });
                
                cbAudioDevice.addActionListener(new ActionListener() {
                        public void
                        actionPerformed(ActionEvent e) { setBackendAudioDevice(); }
                });
                
                channel.getModel().addSamplerChannelListener(new SamplerChannelAdapter() {
                        public void
                        channelChanged(SamplerChannelEvent e) { updateChannelProperties(); }
                });
                
                CC.getSamplerModel().addMidiDeviceListListener(getHandler());
                CC.getSamplerModel().addAudioDeviceListListener(getHandler());
                
                updateMidiDevices();
                updateAudioDevices();
                updateChannelProperties();
        }
        
        /**
         * Updates the channel settings. This method is invoked when changes to the
         * channel were made.
         */
        private void
        updateChannelProperties() {
                SamplerModel sm = CC.getSamplerModel();
                SamplerChannel sc = channel.getModel().getChannelInfo();
                
                MidiDeviceModel mm = sm.getMidiDeviceModel(sc.getMidiInputDevice());
                AudioDeviceModel am = sm.getAudioDeviceModel(sc.getAudioOutputDevice());
                
                if(isUpdate()) CC.getLogger().warning("Unexpected update state!");
                
                setUpdate(true);
                
                try {
                        cbMidiDevice.setSelectedItem(mm == null ? null : mm.getDeviceInfo());
                        
                        cbEngine.setSelectedItem(sc.getEngine());
                        
                        cbAudioDevice.setSelectedItem(am == null ? null : am.getDeviceInfo());
                } catch(Exception x) {
                        CC.getLogger().log(Level.WARNING, "Unkown error", x);
                }
                
                setUpdate(false);
        }
        
        /**
         * Updates the MIDI device list.
         */
        private void
        updateMidiDevices() {
                SamplerModel sm = CC.getSamplerModel();
                SamplerChannel sc = channel.getModel().getChannelInfo();
                
                setUpdate(true);
                
                try {
                        cbMidiDevice.removeAllItems();
                
                        for(MidiDeviceModel m : sm.getMidiDeviceModels())
                                cbMidiDevice.addItem(m.getDeviceInfo());
                
                        MidiDeviceModel mm = sm.getMidiDeviceModel(sc.getMidiInputDevice());
                        cbMidiDevice.setSelectedItem(mm == null ? null : mm.getDeviceInfo());
                } catch(Exception x) {
                        CC.getLogger().log(Level.WARNING, "Unkown error", x);
                }
                 
                setUpdate(false);
        }
        
        /**
         * Updates the audio device list.
         */
        private void
        updateAudioDevices() {
                SamplerModel sm = CC.getSamplerModel();
                SamplerChannel sc = channel.getModel().getChannelInfo();
                
                setUpdate(true);
                
                try {
                        cbAudioDevice.removeAllItems();
                
                        for(AudioDeviceModel m : sm.getAudioDeviceModels()) 
                                cbAudioDevice.addItem(m.getDeviceInfo());
                
                        AudioDeviceModel am = sm.getAudioDeviceModel(sc.getAudioOutputDevice());
                        cbAudioDevice.setSelectedItem(am == null ? null : am.getDeviceInfo());
                } catch(Exception x) {
                        CC.getLogger().log(Level.WARNING, "Unkown error", x);
                }
                
                setUpdate(false);
        }
        
        private void
        setMidiDevice() {
                MidiInputDevice mid = (MidiInputDevice)cbMidiDevice.getSelectedItem();
                
                if(!isUpdate()) {
                        if(mid != null) {
                                channel.getModel().setBackendMidiInputDevice(mid.getDeviceId());
                        }
                        
                        return;
                }
                
                cbMidiPort.removeAllItems();
                
                if(mid == null) {
                        cbMidiPort.setEnabled(false);
                        
                        cbMidiChannel.setSelectedItem(null);
                        cbMidiChannel.setEnabled(false);
                } else {
                        cbMidiPort.setEnabled(true);
                        
                        MidiPort[] ports = mid.getMidiPorts();
                        for(MidiPort port : ports) cbMidiPort.addItem(port);
                        
                        int p = channel.getModel().getChannelInfo().getMidiInputPort();
                        cbMidiPort.setSelectedItem(p >= 0 && p < ports.length ? ports[p] : null);
                        
                        cbMidiChannel.setEnabled(true);
                        int c = channel.getModel().getChannelInfo().getMidiInputChannel();
                        cbMidiChannel.setSelectedItem(c == -1 ? "All" : "Channel " + (c + 1));
                }
        }
        
        private void
        setMidiPort() {
                if(isUpdate()) return;
                
                channel.getModel().setBackendMidiInputPort(cbMidiPort.getSelectedIndex());
        }
        
        private void
        setMidiChannel() {
                if(isUpdate()) return;
                
                Object o = cbMidiChannel.getSelectedItem();
                if(o == null) return;
                String s = o.toString();
                
                int c = s.equals("All") ? -1 : Integer.parseInt(s.substring(8)) - 1;
                
                channel.getModel().setBackendMidiInputChannel(c);
        }
        
        /** Invoked when the user selects an engine. */
        private void
        setEngineType() {
                Object oldEngine = channel.getModel().getChannelInfo().getEngine();
                SamplerEngine newEngine = (SamplerEngine)cbEngine.getSelectedItem();
                
                if(oldEngine != null) { if(oldEngine.equals(newEngine)) return; }
                else if(newEngine == null) return;
                
                channel.getModel().setBackendEngineType(newEngine.getName());
                
        }
        
        private void
        setBackendAudioDevice() {
                if(isUpdate()) return;
                AudioOutputDevice dev = (AudioOutputDevice)cbAudioDevice.getSelectedItem();
                if(dev != null) channel.getModel().setBackendAudioOutputDevice(dev.getDeviceId());
        }
        
        /**
         * Determines whether the currently processed changes are due to update.
         * @return <code>true</code> if the currently processed changes are due to update and
         * <code>false</code> if the currently processed changes are due to user input.
         */
        private boolean
        isUpdate() { return update; }
        
        /**
         * Sets whether the currently processed changes are due to update.
         * @param b Specify <code>true</code> to indicate that the currently 
         * processed changes are due to update; <code>false</code> 
         * indicates that the currently processed changes are due to user input.
         */
        private void
        setUpdate(boolean b) { update = b; }
        
        private final Handler handler = new Handler();
        
        private Handler
        getHandler() { return handler; }
        
        private class Handler implements MidiDeviceListListener, ListListener<AudioDeviceModel> {
                /**
                 * Invoked when a new MIDI device is created.
                 * @param e A <code>MidiDeviceListEvent</code>
                 * instance providing the event information.
                 */
                public void
                deviceAdded(MidiDeviceListEvent e) {
                        cbMidiDevice.addItem(e.getMidiDeviceModel().getDeviceInfo());
                }
        
                /**
                 * Invoked when a MIDI device is removed.
                 * @param e A <code>MidiDeviceListEvent</code>
                 * instance providing the event information.
                 */
                public void
                deviceRemoved(MidiDeviceListEvent e) {
                        cbMidiDevice.removeItem(e.getMidiDeviceModel().getDeviceInfo());
                }
                
                /**
                 * Invoked when a new audio device is created.
                 * @param e An <code>AudioDeviceListEvent</code>
                 * instance providing the event information.
                 */
                public void
                entryAdded(ListEvent<AudioDeviceModel> e) {
                        cbAudioDevice.addItem(e.getEntry().getDeviceInfo());
                }
        
                /**
                 * Invoked when an audio device is removed.
                 * @param e An <code>AudioDeviceListEvent</code>
                 * instance providing the event information.
                 */
                public void
                entryRemoved(ListEvent<AudioDeviceModel> e) {
                        cbAudioDevice.removeItem(e.getEntry().getDeviceInfo());
                }
        }
}