[Ch14] Book version of MiniMusicPlayer3

package ch14;

import javax.sound.midi.*;

import java.io.*;

import javax.swing.*;

import java.awt.*;

public class MiniMusicPlayer3 {

     static JFrame f = new JFrame("My First Music Video");

     static MyDrawPanel ml;

     public static void main(String[] args) {

           MiniMusicPlayer3 mini = new MiniMusicPlayer3();

           mini.go();

     } // close method

     public  void setUpGui() {

        ml = new MyDrawPanel();

        f.setContentPane(ml);

        f.setBounds(30,30, 300,300);

        f.setVisible(true);

    } // close method

    public void go() {

       setUpGui();

       try {

          Sequencer sequencer = MidiSystem.getSequencer();         

          sequencer.open();       

          sequencer.addControllerEventListener(ml, new int[] {127});

          Sequence seq = new Sequence(Sequence.PPQ, 4);

          Track track = seq.createTrack();     

          int r = 0;

          for (int i = 0; i < 60; i+= 4) {

             r = (int) ((Math.random() * 50) + 1);        

             track.add(makeEvent(144,1,r,100,i));        

             track.add(makeEvent(176,1,127,0,i));         

             track.add(makeEvent(128,1,r,100,i + 2));

          } // end loop

          sequencer.setSequence(seq);

          sequencer.start();

          sequencer.setTempoInBPM(120);

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

    } // close method

   public MidiEvent makeEvent(int comd, int chan, int one, int two, int tick) {

       MidiEvent event = null;

       try {

          ShortMessage a = new ShortMessage();

          a.setMessage(comd, chan, one, two);

           event = new MidiEvent(a, tick);

        }catch(Exception e) { }

        return event;

    } // close method

 class MyDrawPanel extends JPanel implements ControllerEventListener {     

      boolean msg = false;

      public void controlChange(ShortMessage event) {

         msg = true;       

         repaint();         

      }

      public void paintComponent(Graphics g) {

       if (msg) {

         int r = (int) (Math.random() * 250);

         int gr = (int) (Math.random() * 250);

         int b = (int) (Math.random() * 250);

         g.setColor(new Color(r,gr,b));

         int ht = (int) ((Math.random() * 120) + 10);

         int width = (int) ((Math.random() * 120) + 10);

         int x = (int) ((Math.random() * 40) + 10);

         int y = (int) ((Math.random() * 40) + 10);

         g.fillRect(x,y,ht, width);

         msg = false;

       } // close if

     } // close method

   }  // close inner class

} // close class     

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