public void setTags(List<String> _tags){
		if(_tags.size() != 0){
			this.tags.clear();
			this.tags = _tags;
			
			Iterator<String> itr = this.tags.iterator();
			
			this.map.clear();
			while(itr.hasNext()){
				String o = itr.next();
				int occurrences = Collections.frequency(this.tags, o);
				this.map.put(o, occurrences);
			}
			
			setChanged();
			notifyObservers(this);
		}
	}