public void setAudioData(AudioData audioData, AudioKey audioKey) {
        if (data != null) {
            throw new IllegalStateException("Cannot change data once it's set");
        }

        data = audioData;
        this.audioKey = audioKey;
    }
Set the audio data to use for the audio. Note that this method
can only be called once, if for example the audio node was initialized
without an {@link AudioData}.

@param audioData The audio data contains the audio track to play.
@param audioKey The audio key that was used to load the AudioData
jme3-core/src/main/java/com/jme3/audio/AudioNode.java