void setHead(LNode n) { head = n; if (head != null) { head.addArc(this, (directed) ? LEdge.INCOMING : LEdge.UNDIRECTED); } }
void setTail(LNode n) { tail = n; if (tail != null) { tail.addArc(this, (directed) ? LEdge.OUTGOING : LEdge.UNDIRECTED); } }