block_mutex.notify();
block_mutex.notifyAll();
    public void receiveDownEvent(Event evt) {	if(evt.getType() == Event.BLOCK_OK) { // priority handling, otherwise FLUSH would block !	    synchronized(down_queue) {		Event event;		try {		    while(down_queue.size() > 0) {			event=(Event)down_queue.remove(10); // wait 10ms at most; queue is *not* empty !			down(event);		    }		}		catch(Exception e) {}	    }	    synchronized(block_mutex) {		block_mutex.notify();	    }	    return;	}	super.receiveDownEvent(evt);    }