public void add(Object o) {
		int nodeLoc = v.findEmpty();
		if(nodeLoc == -1) {
			nodeLoc = v.size();
		}
		v.set(nodeLoc, new Node(o, -1));
		if ( last != -1 ) {
			Node lastNode = (Node)v.get(last);
			lastNode.next = nodeLoc;
		}
		last = nodeLoc;

		if ( first == -1) {
			first = nodeLoc;
		}
		size++;
	}