@Override
	public Collection<Session> getSessionsForTopic(String topic) {
		Collection<Session> result;
		if (map.containsKey(topic)) {
			return Collections.unmodifiableCollection(map.get(topic));
		} else {
			result = Collections.EMPTY_LIST;
		}
		return result;
	}
@ Override public Collection < Session > getSessionsForTopic ( String topic ) { Collection < Session > result ; if ( map . containsKey ( topic ) ) { return Collections . unmodifiableCollection ( map . get ( topic ) ) ; } else { result = Collections . EMPTY_LIST ; } return result ; }
Get Sessions for topics

@param topic
@return