class Jsapi20SynthesizedOutput implements SynthesizedOutput, SpeakableListener, SynthesizerListener,
        AudioSource {

    @Override
    public void waitQueueEmpty() {
        if (LOGGER.isDebugEnabled()) {
            LOGGER.debug("waiting for empty queue...");
        }
        while (!queuedSpeakables.isEmpty()) {
            synchronized (emptyLock) {
                try {
                    emptyLock.wait(WAIT_EMPTY_TIMEINTERVALL);
                } catch (InterruptedException e) {
                    return;
                }
            }
        }
        if (LOGGER.isDebugEnabled()) {
            LOGGER.debug("...queue emptied");
        }
    }

    public  Jsapi20SynthesizedOutput(final SynthesizerMode defaultDescriptor,
            final OutputMediaLocatorFactory mediaLocatorFactory);

}