package org.webswing.audio;

import javax.sound.sampled.Mixer;
import javax.sound.sampled.Mixer.Info;
import javax.sound.sampled.spi.MixerProvider;

public class AudioMixerProvider extends MixerProvider {
	
	private static AudioMixer globalmixer;
	private static Info globalmixerInfo;

    static Thread lockthread;

    static final Object mutex = new Object();

    @Override
    public Mixer getMixer(Info info) {
    	initGlobalMixer();
    	
        if (!(info == null || info == globalmixerInfo)) {
            throw new IllegalArgumentException("Mixer " + info.toString() + " not supported by this provider.");
        }
        
        synchronized (mutex) {
            if (lockthread != null) {
            	if (Thread.currentThread() == lockthread) {
            		throw new IllegalArgumentException("Mixer " + info.toString() + " not supported by this provider.");
            	}
            }
            return globalmixer;
        }
    }

    @Override
    public Info[] getMixerInfo() {
    	initGlobalMixer();
        return new Info[] { globalmixerInfo };
    }
    
    private void initGlobalMixer() {
    	if (globalmixer == null) {
    		globalmixer = new AudioMixer();
    		globalmixerInfo = globalmixer.getMixerInfo();
    	}
    }

}