在Java中使用swing实现一个录音功能

/*
 * @(#)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 &#63; 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 &#63; 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 &#63; 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);
  }
}