@Override
    public float getVolume() {
        return volume;
    }
For streaming music only. (May need to loop.)

@param ar for rendering audio (not null)
@param am the AssetManager for loading assets (not null)
@param fileName the path to the audio asset (not null)
jme3-niftygui/src/main/java/com/jme3/niftygui/SoundHandleJme.java