protected abstract EdgeType createEdge(VertexType source, VertexType target);
public EdgeType createEdge(VertexType source, VertexType target) { EdgeType edge = allocateEdge(source, target); edgeList.add(edge); source.addOutgoingEdge(edge); target.addIncomingEdge(edge); edge.setLabel(maxEdgeLabel++); return edge; }
	protected abstract EdgeType createEdge(VertexType source, VertexType target);