ArrayList<String> processQueryCollection() throws BusinessException{
		
		ArrayList<String> commonSpaceIDs = new ArrayList<String>();
		ArrayList<String> firstSetOfIds = new ArrayList<String>();

		Set<Triple> currentQueryTriples = null;
		
		for(int i=0; i< queryCollection.size();i++){
			String temp = queryCollection.get(i);
			currentQueryTriples = (Set<Triple>) KnowledgeGraph.getInstance().executeQuery(temp);
			if(currentQueryTriples == null) throw new BusinessException("No OfficeSpcae matches your search criteria.");
			
			Iterator<Triple> spaceTriple = currentQueryTriples.iterator();
			if(i == 0){
				while(spaceTriple.hasNext()){
					Triple curTriple = spaceTriple.next();
					firstSetOfIds.add(curTriple.getSubject().getIdentifier());
				}
			}
			if(i > 0){
				while(spaceTriple.hasNext()){
					Triple curTriple = spaceTriple.next();
					String foundID = curTriple.getSubject().getIdentifier();
					if(!commonSpaceIDs.contains(foundID)) commonSpaceIDs.add(foundID);
				}
				firstSetOfIds.retainAll(commonSpaceIDs);		// Get only common office space matching all criteria of each query.
			}
			
		}
		if (firstSetOfIds.size() == 0) throw new BusinessException("No OfficeSpcae matches your search criteria.");
		
		return firstSetOfIds;
	}