Java swing实现支持录音等功能的钢琴程序

今天给大家介绍一下Java实现钢琴的小程序，程序虽小，功能挺多，支持循环播放，录音等功能，首先简单介绍下源码结构：
先看看钢琴界面实现，添加相应滴监听事件：
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									/*

									 * @(#)MidiSynth.java 1.15 99/12/03

									 *

									 * Copyright (c) 1999 Sun Microsystems, Inc. All Rights Reserved.

									 *

									 * Sun grants you ("Licensee") a non-exclusive, royalty free, license to use,

									 * modify and redistribute this software in source and binary code form,

									 * provided that i) this copyright notice and license appear on all copies of

									 * the software; and ii) Licensee does not utilize the software in a manner

									 * which is disparaging to Sun.

									 *

									 * This software is provided "AS IS," without a warranty of any kind. ALL

									 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY

									 * IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR

									 * NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE

									 * LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING

									 * OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS

									 * LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,

									 * INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER

									 * CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF

									 * OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE

									 * POSSIBILITY OF SUCH DAMAGES.

									 *

									 * This software is not designed or intended for use in on-line control of

									 * aircraft, air traffic, aircraft navigation or aircraft communications; or in

									 * the design, construction, operation or maintenance of any nuclear

									 * facility. Licensee represents and warrants that it will not use or

									 * redistribute the Software for such purposes.

									 */

									import java.awt.*;

									import java.awt.event.*;

									import javax.swing.*;

									import javax.swing.border.*;

									import javax.swing.table.*;

									import javax.swing.event.*;

									import javax.sound.midi.*;

									import java.util.Vector;

									import java.io.File;

									import java.io.IOException;

									/**

									 * Illustrates general MIDI melody instruments and MIDI controllers.

									 *

									 * @version @(#)MidiSynth.java 1.15 99/12/03

									 * @author Brian Lichtenwalter 

									 */

									public class MidiSynth extends JPanel implements ControlContext {

									  final int PROGRAM = 192;

									  final int NOTEON = 144;

									  final int NOTEOFF = 128;

									  final int SUSTAIN = 64;

									  final int REVERB = 91;

									  final int ON = 0, OFF = 1;

									  final Color jfcBlue = new Color(204, 204, 255);

									  final Color pink = new Color(255, 175, 175);

									  Sequencer sequencer;

									  Sequence sequence;

									  Synthesizer synthesizer;

									  Instrument instruments[];

									  ChannelData channels[];

									  ChannelData cc;  // current channel

									  JCheckBox mouseOverCB = new JCheckBox("mouseOver", true);

									  JSlider veloS, presS, bendS, revbS;

									  JCheckBox soloCB, monoCB, muteCB, sustCB; 

									  Vector keys = new Vector();

									  Vector whiteKeys = new Vector();

									  JTable table;

									  Piano piano;

									  boolean record;

									  Track track;

									  long startTime;

									  RecordFrame recordFrame;

									  Controls controls;

									  public MidiSynth() {

									    setLayout(new BorderLayout());

									    JPanel p = new JPanel();

									    p.setLayout(new BoxLayout(p, BoxLayout.Y_AXIS));

									    EmptyBorder eb = new EmptyBorder(5,5,5,5);

									    BevelBorder bb = new BevelBorder(BevelBorder.LOWERED);

									    CompoundBorder cb = new CompoundBorder(eb,bb);

									    p.setBorder(new CompoundBorder(cb,eb));

									    JPanel pp = new JPanel(new BorderLayout());

									    pp.setBorder(new EmptyBorder(10,20,10,5));

									    pp.add(piano = new Piano());

									    p.add(pp);

									    p.add(controls = new Controls());

									    p.add(new InstrumentsTable());

									    add(p);

									  }

									  public void open() {

									    try {

									      if (synthesizer == null) {

									        if ((synthesizer = MidiSystem.getSynthesizer()) == null) {

									          System.out.println("getSynthesizer() failed!");

									          return;

									        }

									      } 

									      synthesizer.open();

									      sequencer = MidiSystem.getSequencer();

									      sequence = new Sequence(Sequence.PPQ, 10);

									    } catch (Exception ex) { ex.printStackTrace(); return; }

									    Soundbank sb = synthesizer.getDefaultSoundbank();

									 if (sb != null) {

									      instruments = synthesizer.getDefaultSoundbank().getInstruments();

									      synthesizer.loadInstrument(instruments[0]);

									    }

									    MidiChannel midiChannels[] = synthesizer.getChannels();

									    channels = new ChannelData[midiChannels.length];

									    for (int i = 0; i < channels.length; i++) {

									      channels[i] = new ChannelData(midiChannels[i], i);

									    }

									    cc = channels[0];

									    ListSelectionModel lsm = table.getSelectionModel();

									    lsm.setSelectionInterval(0,0);

									    lsm = table.getColumnModel().getSelectionModel();

									    lsm.setSelectionInterval(0,0);

									  }

									  public void close() {

									    if (synthesizer != null) {

									      synthesizer.close();

									    }

									    if (sequencer != null) {

									      sequencer.close();

									    }

									    sequencer = null;

									    synthesizer = null;

									    instruments = null;

									    channels = null;

									    if (recordFrame != null) {

									      recordFrame.dispose();

									      recordFrame = null;

									    }

									  }

									  /**

									   * given 120 bpm:

									   *  (120 bpm) / (60 seconds per minute) = 2 beats per second

									   *  2 / 1000 beats per millisecond

									   *  (2 * resolution) ticks per second

									   *  (2 * resolution)/1000 ticks per millisecond, or 

									   *   (resolution / 500) ticks per millisecond

									   *  ticks = milliseconds * resolution / 500

									   */

									  public void createShortEvent(int type, int num) {

									    ShortMessage message = new ShortMessage();

									    try {

									      long millis = System.currentTimeMillis() - startTime;

									      long tick = millis * sequence.getResolution() / 500;

									      message.setMessage(type+cc.num, num, cc.velocity); 

									      MidiEvent event = new MidiEvent(message, tick);

									      track.add(event);

									    } catch (Exception ex) { ex.printStackTrace(); }

									  }

									  /**

									   * Black and white keys or notes on the piano.

									   */

									  class Key extends Rectangle {

									    int noteState = OFF;

									    int kNum;

									    public Key(int x, int y, int width, int height, int num) {

									      super(x, y, width, height);

									      kNum = num;

									    }

									    public boolean isNoteOn() {

									      return noteState == ON;

									    }

									    public void on() {

									      setNoteState(ON);

									      cc.channel.noteOn(kNum, cc.velocity);

									      if (record) {

									        createShortEvent(NOTEON, kNum);

									      }

									    }

									    public void off() {

									      setNoteState(OFF);

									      cc.channel.noteOff(kNum, cc.velocity);

									      if (record) {

									        createShortEvent(NOTEOFF, kNum);

									      }

									    }

									    public void setNoteState(int state) {

									      noteState = state;

									    }

									  } // End class Key

									  /**

									   * Piano renders black & white keys and plays the notes for a MIDI 

									   * channel. 

									   */

									  class Piano extends JPanel implements MouseListener {

									    Vector blackKeys = new Vector();

									    Key prevKey;

									    final int kw = 16, kh = 80;

									    public Piano() {

									      setLayout(new BorderLayout());

									      setPreferredSize(new Dimension(42*kw, kh+1));

									      int transpose = 24; 

									      int whiteIDs[] = { 0, 2, 4, 5, 7, 9, 11 }; 

									      for (int i = 0, x = 0; i < 6; i++) {

									        for (int j = 0; j < 7; j++, x += kw) {

									          int keyNum = i * 12 + whiteIDs[j] + transpose;

									          whiteKeys.add(new Key(x, 0, kw, kh, keyNum));

									        }

									      }

									      for (int i = 0, x = 0; i < 6; i++, x += kw) {

									        int keyNum = i * 12 + transpose;

									        blackKeys.add(new Key((x += kw)-4, 0, kw/2, kh/2, keyNum+1));

									        blackKeys.add(new Key((x += kw)-4, 0, kw/2, kh/2, keyNum+3));

									        x += kw;

									        blackKeys.add(new Key((x += kw)-4, 0, kw/2, kh/2, keyNum+6));

									        blackKeys.add(new Key((x += kw)-4, 0, kw/2, kh/2, keyNum+8));

									        blackKeys.add(new Key((x += kw)-4, 0, kw/2, kh/2, keyNum+10));

									      }

									      keys.addAll(blackKeys);

									      keys.addAll(whiteKeys);

									      addMouseMotionListener(new MouseMotionAdapter() {

									        public void mouseMoved(MouseEvent e) {

									          if (mouseOverCB.isSelected()) {

									            Key key = getKey(e.getPoint());

									            if (prevKey != null && prevKey != key) {

									              prevKey.off();

									            } 

									            if (key != null && prevKey != key) {

									              key.on();

									            }

									            prevKey = key;

									            repaint();

									          }

									        }

									      });

									      addMouseListener(this);

									    }

									    public void mousePressed(MouseEvent e) { 

									      prevKey = getKey(e.getPoint());

									      if (prevKey != null) {

									        prevKey.on();

									        repaint();

									      }

									    }

									    public void mouseReleased(MouseEvent e) { 

									      if (prevKey != null) {

									        prevKey.off();

									        repaint();

									      }

									    }

									    public void mouseExited(MouseEvent e) { 

									      if (prevKey != null) {

									        prevKey.off();

									        repaint();

									        prevKey = null;

									      }

									    }

									    public void mouseClicked(MouseEvent e) { }

									    public void mouseEntered(MouseEvent e) { }

									    public Key getKey(Point point) {

									      for (int i = 0; i < keys.size(); i++) {

									        if (((Key) keys.get(i)).contains(point)) {

									          return (Key) keys.get(i);

									        }

									      }

									      return null;

									    }

									    public void paint(Graphics g) {

									      Graphics2D g2 = (Graphics2D) g;

									      Dimension d = getSize();

									      g2.setBackground(getBackground());

									      g2.clearRect(0, 0, d.width, d.height);

									      g2.setColor(Color.white);

									      g2.fillRect(0, 0, 42*kw, kh);

									      for (int i = 0; i < whiteKeys.size(); i++) {

									        Key key = (Key) whiteKeys.get(i);

									        if (key.isNoteOn()) {

									          g2.setColor(record ? pink : jfcBlue);

									          g2.fill(key);

									        }

									        g2.setColor(Color.black);

									        g2.draw(key);

									      }

									      for (int i = 0; i < blackKeys.size(); i++) {

									        Key key = (Key) blackKeys.get(i);

									        if (key.isNoteOn()) {

									          g2.setColor(record ? pink : jfcBlue);

									          g2.fill(key);

									          g2.setColor(Color.black);

									          g2.draw(key);

									        } else {

									          g2.setColor(Color.black);

									          g2.fill(key);

									        }

									      }

									    }

									  } // End class Piano

									  /**

									   * Stores MidiChannel information.

									   */

									  class ChannelData {

									    MidiChannel channel;

									    boolean solo, mono, mute, sustain;

									    int velocity, pressure, bend, reverb;

									    int row, col, num;

									    public ChannelData(MidiChannel channel, int num) {

									      this.channel = channel;

									      this.num = num;

									      velocity = pressure = bend = reverb = 64;

									    }

									    public void setComponentStates() {

									      table.setRowSelectionInterval(row, row);

									      table.setColumnSelectionInterval(col, col);

									      soloCB.setSelected(solo);

									      monoCB.setSelected(mono);

									      muteCB.setSelected(mute);

									      //sustCB.setSelected(sustain);

									      JSlider slider[] = { veloS, presS, bendS, revbS };

									      int v[] = { velocity, pressure, bend, reverb };

									      for (int i = 0; i < slider.length; i++) {

									        TitledBorder tb = (TitledBorder) slider[i].getBorder();

									        String s = tb.getTitle();

									        tb.setTitle(s.substring(0, s.indexOf('=')+1)+s.valueOf(v[i]));

									        slider[i].repaint();

									      }

									    }

									  } // End class ChannelData

									  /**

									   * Table for 128 general MIDI melody instuments.

									   */

									  class InstrumentsTable extends JPanel {

									    private String names[] = { 

									      "Piano", "Chromatic Perc.", "Organ", "Guitar", 

									      "Bass", "Strings", "Ensemble", "Brass", 

									      "Reed", "Pipe", "Synth Lead", "Synth Pad",

									      "Synth Effects", "Ethnic", "Percussive", "Sound Effects" };

									    private int nRows = 8;

									    private int nCols = names.length; // just show 128 instruments

									    public InstrumentsTable() {

									      setLayout(new BorderLayout());

									      TableModel dataModel = new AbstractTableModel() {

									        public int getColumnCount() { return nCols; }

									        public int getRowCount() { return nRows;}

									        public Object getValueAt(int r, int c) { 

									          if (instruments != null) {

									            return instruments[c*nRows+r].getName();

									          } else {

									            return Integer.toString(c*nRows+r);

									          }

									        }

									        public String getColumnName(int c) { 

									          return names[c];

									        }

									        public Class getColumnClass(int c) {

									          return getValueAt(0, c).getClass();

									        }

									        public boolean isCellEditable(int r, int c) {return false;}

									        public void setValueAt(Object obj, int r, int c) {}

									      };

									      table = new JTable(dataModel);

									      table.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);

									      // Listener for row changes

									      ListSelectionModel lsm = table.getSelectionModel();

									      lsm.addListSelectionListener(new ListSelectionListener() {

									        public void valueChanged(ListSelectionEvent e) {

									          ListSelectionModel sm = (ListSelectionModel) e.getSource();

									          if (!sm.isSelectionEmpty()) {

									            cc.row = sm.getMinSelectionIndex();

									          }

									          programChange(cc.col*nRows+cc.row);

									        }

									      });

									      // Listener for column changes

									      lsm = table.getColumnModel().getSelectionModel();

									      lsm.addListSelectionListener(new ListSelectionListener() {

									        public void valueChanged(ListSelectionEvent e) {

									          ListSelectionModel sm = (ListSelectionModel) e.getSource();

									          if (!sm.isSelectionEmpty()) {

									            cc.col = sm.getMinSelectionIndex();

									          }

									          programChange(cc.col*nRows+cc.row);

									        }

									      });

									      table.setPreferredScrollableViewportSize(new Dimension(nCols*110, 200));

									      table.setCellSelectionEnabled(true);

									      table.setColumnSelectionAllowed(true);

									      for (int i = 0; i < names.length; i++) {

									        TableColumn column = table.getColumn(names[i]);

									        column.setPreferredWidth(110);

									      }

									      table.setAutoResizeMode(table.AUTO_RESIZE_OFF);

									      JScrollPane sp = new JScrollPane(table);

									      sp.setVerticalScrollBarPolicy(sp.VERTICAL_SCROLLBAR_NEVER);

									      sp.setHorizontalScrollBarPolicy(sp.HORIZONTAL_SCROLLBAR_ALWAYS);

									      add(sp);

									    }

									    public Dimension getPreferredSize() {

									      return new Dimension(800,170);

									    }

									    public Dimension getMaximumSize() {

									      return new Dimension(800,170);

									    }

									    private void programChange(int program) {

									      if (instruments != null) {

									        synthesizer.loadInstrument(instruments[program]);

									      }

									      cc.channel.programChange(program);

									      if (record) {

									        createShortEvent(PROGRAM, program);

									      }

									    }

									  }

									  /**

									   * A collection of MIDI controllers.

									   */

									  class Controls extends JPanel implements ActionListener, ChangeListener, ItemListener {

									    public JButton recordB;

									    JMenu menu;

									    int fileNum = 0;

									    public Controls() {

									      setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));

									      setBorder(new EmptyBorder(5,10,5,10));

									      JPanel p = new JPanel();

									      p.setLayout(new BoxLayout(p, BoxLayout.X_AXIS));

									      veloS = createSlider("Velocity", p);

									      presS = createSlider("Pressure", p);

									      revbS = createSlider("Reverb", p);

									  // create a slider with a 14-bit range of values for pitch-bend

									      bendS = create14BitSlider("Bend", p);

									      p.add(Box.createHorizontalStrut(10));

									      add(p);

									      p = new JPanel();

									      p.setBorder(new EmptyBorder(10,0,10,0));

									      p.setLayout(new BoxLayout(p, BoxLayout.X_AXIS));

									      JComboBox combo = new JComboBox();

									      combo.setPreferredSize(new Dimension(120,25));

									      combo.setMaximumSize(new Dimension(120,25));

									      for (int i = 1; i <= 16; i++) {

									        combo.addItem("Channel " + String.valueOf(i));

									      } 

									      combo.addItemListener(this);

									      p.add(combo);

									      p.add(Box.createHorizontalStrut(20));

									      muteCB = createCheckBox("Mute", p);

									      soloCB = createCheckBox("Solo", p);

									      monoCB = createCheckBox("Mono", p);

									      //sustCB = createCheckBox("Sustain", p);

									      createButton("All Notes Off", p);

									      p.add(Box.createHorizontalStrut(10));

									      p.add(mouseOverCB);

									      p.add(Box.createHorizontalStrut(10));

									      recordB = createButton("Record...", p);

									      add(p);

									    }

									    public JButton createButton(String name, JPanel p) {

									      JButton b = new JButton(name);

									      b.addActionListener(this);

									      p.add(b);

									      return b;

									    }

									    private JCheckBox createCheckBox(String name, JPanel p) {

									      JCheckBox cb = new JCheckBox(name);

									      cb.addItemListener(this);

									      p.add(cb);

									      return cb;

									    }

									    private JSlider createSlider(String name, JPanel p) {

									      JSlider slider = new JSlider(JSlider.HORIZONTAL, 0, 127, 64);

									      slider.addChangeListener(this);

									      TitledBorder tb = new TitledBorder(new EtchedBorder());

									      tb.setTitle(name + " = 64");

									      slider.setBorder(tb);

									      p.add(slider);

									      p.add(Box.createHorizontalStrut(5));

									      return slider;

									    }

									    private JSlider create14BitSlider(String name, JPanel p) {

									      JSlider slider = new JSlider(JSlider.HORIZONTAL, 0, 16383, 8192);

									      slider.addChangeListener(this);

									      TitledBorder tb = new TitledBorder(new EtchedBorder());

									      tb.setTitle(name + " = 8192");

									      slider.setBorder(tb);

									      p.add(slider);

									      p.add(Box.createHorizontalStrut(5));

									      return slider;

									    }

									    public void stateChanged(ChangeEvent e) {

									      JSlider slider = (JSlider) e.getSource();

									      int value = slider.getValue();

									      TitledBorder tb = (TitledBorder) slider.getBorder();

									      String s = tb.getTitle();

									      tb.setTitle(s.substring(0, s.indexOf('=')+1) + s.valueOf(value));

									      if (s.startsWith("Velocity")) {

									        cc.velocity = value;

									      } else if (s.startsWith("Pressure")) {

									        cc.channel.setChannelPressure(cc.pressure = value);

									      } else if (s.startsWith("Bend")) {

									        cc.channel.setPitchBend(cc.bend = value);

									      } else if (s.startsWith("Reverb")) {

									        cc.channel.controlChange(REVERB, cc.reverb = value);

									      }

									      slider.repaint();

									    }

									    public void itemStateChanged(ItemEvent e) {

									      if (e.getSource() instanceof JComboBox) {

									        JComboBox combo = (JComboBox) e.getSource();

									        cc = channels[combo.getSelectedIndex()];

									        cc.setComponentStates();

									      } else {

									        JCheckBox cb = (JCheckBox) e.getSource();

									        String name = cb.getText();

									        if (name.startsWith("Mute")) {

									          cc.channel.setMute(cc.mute = cb.isSelected());

									        } else if (name.startsWith("Solo")) {

									          cc.channel.setSolo(cc.solo = cb.isSelected());

									        } else if (name.startsWith("Mono")) {

									          cc.channel.setMono(cc.mono = cb.isSelected());

									        } else if (name.startsWith("Sustain")) {

									          cc.sustain = cb.isSelected();

									          cc.channel.controlChange(SUSTAIN, cc.sustain ? 127 : 0);

									        }

									      }

									    }

									    public void actionPerformed(ActionEvent e) {

									      JButton button = (JButton) e.getSource();

									      if (button.getText().startsWith("All")) {

									        for (int i = 0; i < channels.length; i++) {

									          channels[i].channel.allNotesOff();

									        }

									        for (int i = 0; i < keys.size(); i++) {

									          ((Key) keys.get(i)).setNoteState(OFF);

									        }

									      } else if (button.getText().startsWith("Record")) {

									        if (recordFrame != null) {

									          recordFrame.toFront();

									        } else {

									          recordFrame = new RecordFrame();

									        }

									      }

									    }

									  } // End class Controls

									  /**

									   * A frame that allows for midi capture & saving the captured data.

									   */

									  class RecordFrame extends JFrame implements ActionListener, MetaEventListener {

									    public JButton recordB, playB, saveB;

									    Vector tracks = new Vector();

									    DefaultListModel listModel = new DefaultListModel();

									    TableModel dataModel;

									    JTable table;

									    public RecordFrame() {

									      super("Midi Capture");

									      addWindowListener(new WindowAdapter() {

									        public void windowClosing(WindowEvent e) {recordFrame = null;}

									      });

									      sequencer.addMetaEventListener(this);

									      try {

									        sequence = new Sequence(Sequence.PPQ, 10);

									      } catch (Exception ex) { ex.printStackTrace(); }

									      JPanel p1 = new JPanel(new BorderLayout());

									      JPanel p2 = new JPanel();

									      p2.setBorder(new EmptyBorder(5,5,5,5));

									      p2.setLayout(new BoxLayout(p2, BoxLayout.X_AXIS));

									      recordB = createButton("Record", p2, true);

									      playB = createButton("Play", p2, false);

									      saveB = createButton("Save...", p2, false);

									      getContentPane().add("North", p2);

									      final String[] names = { "Channel #", "Instrument" };

									      dataModel = new AbstractTableModel() {

									        public int getColumnCount() { return names.length; }

									        public int getRowCount() { return tracks.size();}

									        public Object getValueAt(int row, int col) { 

									          if (col == 0) {

									            return ((TrackData) tracks.get(row)).chanNum;

									          } else if (col == 1) {

									            return ((TrackData) tracks.get(row)).name;

									          } 

									          return null;

									        }

									        public String getColumnName(int col) {return names[col]; }

									        public Class getColumnClass(int c) {

									          return getValueAt(0, c).getClass();

									        }

									        public boolean isCellEditable(int row, int col) {

									          return false;

									        }

									        public void setValueAt(Object val, int row, int col) { 

									          if (col == 0) {

									            ((TrackData) tracks.get(row)).chanNum = (Integer) val;

									          } else if (col == 1) {

									            ((TrackData) tracks.get(row)).name = (String) val;

									          } 

									        }

									      };

									      table = new JTable(dataModel);

									      TableColumn col = table.getColumn("Channel #");

									      col.setMaxWidth(65);

									      table.sizeColumnsToFit(0);

									      JScrollPane scrollPane = new JScrollPane(table);

									      EmptyBorder eb = new EmptyBorder(0,5,5,5);

									      scrollPane.setBorder(new CompoundBorder(eb,new EtchedBorder()));

									   getContentPane().add("Center", scrollPane);

									   pack();

									      Dimension d = Toolkit.getDefaultToolkit().getScreenSize();

									      int w = 210;

									      int h = 160;

									      setLocation(d.width/2 - w/2, d.height/2 - h/2);

									      setSize(w, h);

									   setVisible(true);

									    }

									    public JButton createButton(String name, JPanel p, boolean state) {

									      JButton b = new JButton(name);

									      b.setFont(new Font("serif", Font.PLAIN, 10));

									      b.setEnabled(state);

									      b.addActionListener(this);

									      p.add(b);

									      return b;

									    }

									    public void actionPerformed(ActionEvent e) {

									      JButton button = (JButton) e.getSource();

									      if (button.equals(recordB)) {

									        record = recordB.getText().startsWith("Record");

									        if (record) {

									          track = sequence.createTrack();

									          startTime = System.currentTimeMillis();

									          // add a program change right at the beginning of 

									          // the track for the current instrument

									          createShortEvent(PROGRAM,cc.col*8+cc.row);

									          recordB.setText("Stop");

									          playB.setEnabled(false);

									          saveB.setEnabled(false);

									        } else {

									          String name = null;

									          if (instruments != null) {

									            name = instruments[cc.col*8+cc.row].getName();

									          } else {

									            name = Integer.toString(cc.col*8+cc.row);

									          }

									          tracks.add(new TrackData(cc.num+1, name, track)); 

									          table.tableChanged(new TableModelEvent(dataModel));

									          recordB.setText("Record");

									          playB.setEnabled(true);

									          saveB.setEnabled(true);

									        } 

									      } else if (button.equals(playB)) {

									        if (playB.getText().startsWith("Play")) {

									          try {

									            sequencer.open();

									            sequencer.setSequence(sequence);

									          } catch (Exception ex) { ex.printStackTrace(); }

									          sequencer.start();

									          playB.setText("Stop");

									          recordB.setEnabled(false);

									        } else {

									          sequencer.stop();

									          playB.setText("Play");

									          recordB.setEnabled(true);

									        } 

									      } else if (button.equals(saveB)) {

									        try {

									          File file = new File(System.getProperty("user.dir"));

									          JFileChooser fc = new JFileChooser(file);

									          fc.setFileFilter(new javax.swing.filechooser.FileFilter() {

									            public boolean accept(File f) {

									              if (f.isDirectory()) {

									                return true;

									              }

									              return false;

									            }

									            public String getDescription() {

									              return "Save as .mid file.";

									            }

									          });

									          if (fc.showSaveDialog(null) == JFileChooser.APPROVE_OPTION) {

									            saveMidiFile(fc.getSelectedFile());

									          }

									        } catch (SecurityException ex) { 

									          JavaSound.showInfoDialog();

									          ex.printStackTrace();

									        } catch (Exception ex) { 

									          ex.printStackTrace();

									        }

									      }

									    }

									    public void meta(MetaMessage message) {

									      if (message.getType() == 47) { // 47 is end of track

									        playB.setText("Play");

									        recordB.setEnabled(true);

									      }

									    }

									    public void saveMidiFile(File file) {

									      try {

									        int[] fileTypes = MidiSystem.getMidiFileTypes(sequence);

									        if (fileTypes.length == 0) {

									          System.out.println("Can't save sequence");

									        } else {

									          if (MidiSystem.write(sequence, fileTypes[0], file) == -1) {

									            throw new IOException("Problems writing to file");

									          } 

									        }

									      } catch (SecurityException ex) { 

									        JavaSound.showInfoDialog();

									      } catch (Exception ex) { 

									        ex.printStackTrace(); 

									      }

									    }

									    class TrackData extends Object {

									      Integer chanNum; String name; Track track;

									      public TrackData(int chanNum, String name, Track track) {

									        this.chanNum = new Integer(chanNum);

									        this.name = name;

									        this.track = track;

									      }

									    } // End class TrackData

									  } // End class RecordFrame

									  public static void main(String args[]) {

									    final MidiSynth midiSynth = new MidiSynth();

									    midiSynth.open();

									    JFrame f = new JFrame("Midi Synthesizer");

									    f.addWindowListener(new WindowAdapter() {

									      public void windowClosing(WindowEvent e) {System.exit(0);}

									    });

									    f.getContentPane().add("Center", midiSynth);

									    f.pack();

									    Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();

									    int w = 760;

									    int h = 470;

									    f.setLocation(screenSize.width/2 - w/2, screenSize.height/2 - h/2);

									    f.setSize(w, h);

									    f.setVisible(true);

									  }

									}