public synchronized void removeOwner(int id){
		boolean exists = false;
		for(Integer i : owner){
			if(i.intValue() == id){
				owner.remove(i);
				exists = true;
				break;
			}
		}
		if(exists){
			if(writer == id){
				writer = -1;
			}
			for(Integer i : reader_list){
				if(i.intValue() == id){
					reader_list.remove(i);
					break;
				}
			}
		}
	}