How to return audio in a method?

[ad54me]

So I am doing a "Snowman" project for school and I want to output sound/music (whatever's possible) for my program.

I made a method, playAudio(), but I don't know what to classify it as...

import java.awt.*;
import java.awt.event.*;
import java.applet.*;

public class Audio extends Applet
{


Image Buffer;
    Graphics gBuffer;
    boolean pressedLeft=true, pressedRight=false, pressedUp=false, pressedDown=false;
    AudioClip FightingDreamer;
    AudioClip Sign;
    AudioClip SadnessSorrow;
    
    
    
    public void init()
    {
       Buffer=createImage(size().width,size().height);
       gBuffer=Buffer.getGraphics();

       try
       {
            FightingDreamer=getAudioClip(getCodeBase(),"Fighting_Dreamer.wav");
            Sign=getAudioClip(getCodeBase(),"Sign.wav");
            SadnessSorrow=getAudioClip(getCodeBase(),"Sadness_and_Sorrow.wav");
       }//try
       catch (Exception e)
       {
       }//catch
    }//init
	
	public boolean keyDown(Event e, int key)
    {
       if(key==Event.LEFT)
       pressedLeft=true;

       if(key==Event.RIGHT)
       pressedRight=true;

       if(key==Event.UP)
       pressedUp=true;
       if(key==Event.DOWN)
       pressedDown=true;

       if(key=='s'||key=='S')
           Sign.play();

       repaint();

       return true;
    }
	
	public boolean keyUp(Event e, int key)
    {
       pressedLeft=pressedRight=pressedUp=pressedDown=false;

       repaint();

       return true;
    }
    
    public void playAudio(){
	if(pressedLeft)
          return Sign.loop();
      else
          return Sign.stop();
    
    if(pressedRight)
          return SadnessSorrow.loop();
      else
          return SadnessSorrow.stop();
          
    if(pressedUp)
          return FightingDreamer.loop();
      else
          return FightingDreamer.stop();
    
    if(pressedDown)
          return;
      else 
          return;
    }
        
}

I know that for a void method, you can't return anything, so what would I replace "void" with?
Also, there seems to be no error for

if(pressedDown)
          return;
      else 
          return;

So could anyone explain why please?

Thanks in advance! :)

[ozzyman]

Replace "void" with the type of Object or primitive you want to pass back.

In this case, its an AudioClip object. So your method signature should look something like:

public AudioClip getAudioClip();


As for the second question, the following code:

return;

only exits the encapsulating method (without returning anything).

It's useful in some cases, consider the following code for example:

public double calculateSomething(MyObject myObject) {
  if (myObject==null) return;
  //do some heavy processing
  ...
}

that would save doing any unnecessary processing when there is none to be done for certain values/non-values of myObject.

[ad54me]

I changed it to

public AudioClip getAudio(){
	if(pressedLeft)
          return Sign.loop();
      else
          return Sign.stop();
}

But I get an error for incompatible types. What am I doing wrong now?

[ozzyman]

Incompatible type means you are returning the wrong Object.

If I have a class like this:

class Sign {

  private static AnotherObject anotherObject;

  public static AnotherObject loop() {
    ...
    anotherObject = ...;
    return anotherObject;
  }

}

And then I create a method like this:

class SignTest {

    public AnObject getMyObject() { 
       return Sign.loop();
    }

}

Because I told the compiler that I would return AnObject, it expects me to return AnObject.

Instead I returned the whatever the result of Sign.loop() is.

In this case, Sign.loop() returned AnotherObject.

Therefore, the compiler expected AnObject but I gave it AnotherObject.

AnotherObject is not a subclass of AnObject, neither is it an instance of AnObject so it is incompatible with AnObject and there is an error thrown.

[DarrylBurke]

Replace "void" with the type of Object or primitive you want to pass back.

In this case, its an AudioClip object. So your method signature should look something like:

public AudioClip getAudioClip();


As for the second question, the following code:

return;

only exits the encapsulating method (without returning anything).

It's useful in some cases, consider the following code for example:

public double calculateSomething(MyObject myObject) {
  if (myObject==null) return;
  //do some heavy processing
  ...
}

that would save doing any unnecessary processing when there is none to be done for certain values/non-values of myObject.

You can't return; from a method that has a return type other than void. You have to return a value.

db

[ozzyman]

Oh yes of course thanks for spotting that db.