public SequenceListener getListener(
			Class<? extends SequenceListener> listenerClass, int preOrPost) {
		List<SequenceListener> toGet = null;
		if (preOrPost == POST)
			toGet = postTrimListeners;
		if (preOrPost == PRE)
			toGet = preTrimListeners;
		if (toGet == null)
			return null;
		for (SequenceListener l : toGet) {
			if (l.getClass().equals(listenerClass))
				return l;
		}
		return null;
	}