private static BasicDBObject docForQuery(Person person){
		
		BasicDBObject docQuery = new BasicDBObject();
		
		if( !person.getFirstName().equals("")){
			docQuery.append("firstName", person.getFirstName());
		}
		if(!person.getLastName().equals("")){
			docQuery.append("lastName", person.getLastName());
		}
		if(person.getAge()!=0){
			docQuery.append("age", person.getAge());
		}
		
		return docQuery;
		
	}