Question

I’m writing a music player. When I read data from external music file I fill a buffer with amplitude information. Since I figured it would make sense to spawn this blocking action into it’s own thread I added an interface that runs it within runnable :

public class AudioInterface implements Runnable {

 public void run() 
 {
    AudioManager am = new AudioManager();
    am.play("res/sample2.mp3");
 }
}

Here are my following questions :

• How do I create a hook from another class to poll the amplitude data? I need it to write an algorithm that will be drawn onto a JPanel canvas.
• Should the panel that enables visualization also be in a different thread?
• Currently run() only includes playing the file, how would I use this thread for other actions such as posing and seeking etc since there is only one run action.

Thanks

Answer 1

Some thoughts:

How do I create a hook from another class to poll the amplitude data? I need it to write an algorithm that will be drawn onto a JPanel canvas.

Since this is a Swing program, consider using a SwingWorker for your background thread, and then pumping the amplitude data to the GUI portion of the program via SwingWorker’s publish/process method pair.

Should the panel that enables visualization also be in a different thread?

Careful here. All Swing code should be called on one thread and one thread only, the event dispatch thread. Please have a look at the tutorial on this, Concurrency in Swing.

Currently run() only includes playing the file, how would I use this thread for other actions such as posing and seeking etc.

You don’t use “threads” for this, you call methods of objects.

Also, you’ll likely want to declare your AudioManager variable as a class field, not a local variable, since otherwise its scope is limited to the method it was declared in, preventing other code from interacting with it.