Godaigo's plea for help!

[godaigo]

Ben, something like this perhaps? http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=17

[benthehutt]

Yeah! That's a pretty sweet app. I'm more interested in actual synthesis than just adding sound files to an application. Anyway, I started some work on this, but I've got some questions on Java as a whole. What is the difference between Java and J2EE? Also, what good is the Runnable class? I've seen some examples where a guy instantiates a Runnable object and I don't know what the point was.

Here is my code so far. It's pretty simple, it just generates a sine wave and a square wave and plays them back. But let me know if I'm doing anything in Java that's stupid (I'm using Eclipse 3.4.1 Ganymede):

Code Select Expand

import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.SourceDataLine;
import javax.sound.sampled.LineUnavailableException;

import javax.swing.*;
import javax.swing.border.*;
import java.awt.*;
import java.awt.event.*;

public class BasicSound {
	
	// CD Quality audio (well, almost)
	public final float SAMPLE_RATE = 44100;
	
	// Main GUI component
	JFrame mainFrame; 
	
	public static void main( String[] args ){
		BasicSound my_sound = new BasicSound();
		my_sound.showDialog();
	}
	
	public BasicSound(){
		setUpDialog();
	}
	
	public void setUpDialog(){
	    // Main frame
	    mainFrame = new JFrame("Pure Wave Generator");
	    mainFrame.setSize( 300, 300 );
	    Container content = mainFrame.getContentPane();
	    content.setBackground(Color.white);
	    content.setLayout(new FlowLayout()); 
	    
	    // Frequency slider
	    final JSlider slider_hertz = new JSlider( JSlider.HORIZONTAL, 20, 20000, 440 );
	    slider_hertz.setPaintLabels( true );
	    slider_hertz.setToolTipText("In Hertz");
	    slider_hertz.setBorder( new TitledBorder( "Frequency" ) );
	    content.add( slider_hertz );
	    
	    // Sine wave button
	    final JButton btn_play_sine = new JButton( "Play Sine Wave" );
	    btn_play_sine.addActionListener( new ActionListener(){
	    	public void actionPerformed( ActionEvent actionEvent ){
	    		try{
	    			System.out.println("Play sine wave at " + slider_hertz.getValue() + " hertz.");
					generateSineWave( slider_hertz.getValue() );
				}catch( LineUnavailableException err ){
					System.out.println("Line is unavailable.");
				}
	    	}
	    } );
	    content.add( btn_play_sine );
	    
	    // Square wave button
	    final JButton btn_play_square = new JButton( "Play Square Wave" );
	    btn_play_square.addActionListener( new ActionListener(){
	    	public void actionPerformed( ActionEvent actionEvent ){
	    		try{
	    			System.out.println("Play square wave at " + slider_hertz.getValue() + " hertz.");
					generateSquareWave( slider_hertz.getValue() );
				}catch( LineUnavailableException err ){
					System.out.println("Line is unavailable.");
				}
	    	}
	    } );
	    content.add( btn_play_square );
	    
	    mainFrame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
	}
	
	public void showDialog(){
	    mainFrame.setVisible( true );
	}
	
	// Generate a sine wave at a specified frequency
	public void generateSineWave( float hertz ) throws LineUnavailableException{
	    byte[] buf = new byte[1];
	    
	    AudioFormat af = new AudioFormat( SAMPLE_RATE, 8, 1, true, false );
	    
    	SourceDataLine source_dl = AudioSystem.getSourceDataLine( af );
    	source_dl.open( af );
    	
    	for( int i=0; i < SAMPLE_RATE; i++ ){
      		double angle = i / ( SAMPLE_RATE / hertz ) * 2.0 * Math.PI;
      		buf[0]=( byte )( Math.sin( angle ) * 100 );
        	source_dl.write( buf, 0, 1 );
		}
		
		System.out.println("Finished playback.");
		
		source_dl.start();
		source_dl.drain();
		source_dl.stop();
		source_dl.close();
	}
	
	// Generate a square wave at a specified frequency
	public void generateSquareWave( float hertz ) throws LineUnavailableException{
	    byte[] buf = new byte[1];
	    
	    AudioFormat af = new AudioFormat( SAMPLE_RATE, 8, 1, true, false );
	    
    	SourceDataLine source_dl = AudioSystem.getSourceDataLine( af );
    	source_dl.open( af );
    	
    	for( int i=0; i < SAMPLE_RATE; i++ ){
      		double angle = i / ( SAMPLE_RATE / hertz ) * 2.0 * Math.PI;
      		buf[0]=( byte )( ( Math.sin( angle ) > 0 ) ? 100 : -100  );
        	source_dl.write( buf, 0, 1 );
		}
		
		System.out.println("Finished playback.");
		
		source_dl.start();
		source_dl.drain();
		source_dl.stop();
		source_dl.close();
	}
	
}

Also, what is the difference between an ActionListener and an EventListener?

Any help would be appreciated. Thanks!