Question

Is it possible to cast from an InputStream to an AudioInputStream?

I want to play little sound files at certain events, so I made following SoundThread

import java.io.*;
import javax.sound.sampled.*;

public class SoundThread implements Runnable{

    private String filename;

    SoundThread(String filename) {
        this.filename = filename;
    }

    public void run() {
        try {
            InputStream in = ClassLoader.getSystemResourceAsStream("sounds/"+filename+".wav");
            Clip clip = AudioSystem.getClip();
            clip.open((AudioInputStream)in);
            clip.start();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (NullPointerException e) {
            e.printStackTrace();
        } catch (LineUnavailableException e){
            e.printStackTrace();
        } 
    }
}

I run it with

new Thread(new SoundThread("nameOfTheSoundFile")).start();

At the beginning I handled it with the sun.audio.AudioPlayer and sun.audio.AudioStream, but as soon I put that code in eclipse, it showed me errors. So I tried

AudioInputStream in = (AudioInputStream)ClassLoader.getSystemResourceAsStream("sounds/"+filename+".wav");

to cast the InputStream to AudioInputStream (eclipse didn’t show any errors), but running it it throws an ClassCastException. Is there any solution for this problem?

Answer 1

Use the AudioSystem to get an AudioInputStream directly from the URL to the resource.

URL url = ClassLoader.getResource("/sounds/"+filename+".wav");
AudioInputStream ais = AudioSystem.getAudioInputStream(url);
Clip clip = AudioSystem.getClip();
clip.open(ais);

See also AudioSystem.getAudioInputStream(InputStream) but this is ‘more dangerous’. Java Sound will typically require a repositionable input stream. For some reason that I am not quite clear on, the Class.getResourceAsStream() variants sometimes return a non-repositionable stream.