Head First Java Chapter 11, example on page 346

[Mark Nibert]

The issue I am having is where it says MidiEvent = null; I am not sure what is going on but it keeps failing the argument if statement. I also dont see where it is prompting for the user cmd line input. Here is the code:

import javax.sound.midi.*;


public class MiniMiniMusicCmdLine {   // this is the first one
       
     public static void main(String[] args) {
        MiniMiniMusicCmdLine mini = new MiniMiniMusicCmdLine();
        if (args.length < 2) {
            System.out.println("Don't forget the instrument and note args");
        } else {
            int instrument = Integer.parseInt(args[0]);
            int note = Integer.parseInt(args[1]);
            mini.play(instrument, note);
            
        }
     }

    public void play(int instrument, int note) {

      try {
 
         Sequencer player = MidiSystem.getSequencer();         
         player.open();
        
         Sequence seq = new Sequence(Sequence.PPQ, 4);         
         Track track = seq.createTrack();  
          
         MidiEvent event = null;

         ShortMessage first = new ShortMessage();
         first.setMessage(192, 1, instrument, 0);
         MidiEvent changeInstrument = new MidiEvent(first, 1); 
         track.add(changeInstrument);

         
         ShortMessage a = new ShortMessage();
         a.setMessage(144, 1, note, 100);
         MidiEvent noteOn = new MidiEvent(a, 1); 
         track.add(noteOn);

         ShortMessage b = new ShortMessage();
         b.setMessage(128, 1, note, 100);
         MidiEvent noteOff = new MidiEvent(b, 16); 
         track.add(noteOff);
         player.setSequence(seq); 
         player.start();
         // new
	     Thread.sleep(5000);
	     player.close();
         System.exit(0);

      } catch (Exception ex) {ex.printStackTrace();}
  } // close play

} // close class

[Rob Spoor]

Please Use Code Tags. You can edit your post to add them.

[David Newton]

It doesn't prompt for input, it gets the arguments from the command line.

it keeps failing the argument if statement.

I'm not sure what that means.

[Mark Nibert]

When I run it just processes this line System.out.println("Don't forget the instrument and note args");
I am not sure how to get the information in to the program from the command line. I am still pretty new to this and I cant figure it out.

[Nitish Bangera]

I hope you are using the cmd for this.

Now while you give java MiniMiniMusicCmdLine 1 2. any integer should be specified as it takes the input from the command line.

If you want to take the input in the program it self then i guess you can use scanner and console.

[Mark Nibert]

Is that where I am screwing up? I am using eclipse for coding it. I will read through the tutorial and run it from the command line tonight. I swear sometimes my brain doesnt function properly.

[Nitish Bangera]

Well i for starters i don't prefer using an IDE. You better use notepad or Textpad(can compile and execute from inside also) and compile and execute using the command line only. Also if you are using eclipse, find out where can you pass in the parameters. Every IDE has that option where you can specify the command line parameters which needs to be passed.

[Mark Nibert]

Are there any good websites w/ labs that I can work through to help enforce the theories and ideas. I have taken programming classes and I am working on an idea for a program to write that I can use as a demo and to hopefully learn some of the more advanced ideas. I wish I would have kept the ones from college.

[Campbell Ritchie]

Nitish Bangera wrote:Well i for starters i don't prefer using an IDE. You better use notepad or Textpad . . .

Agree. But NotePad is pretty bad for programming. Download NotePad2 or NotePad++ which despite the names are quite different from NotePad.