Node node2=graphModel.factory().newNode("1");
Node node3=graphModel.factory().newNode("2");
directedGraph.addNode(node1);
directedGraph.addNode(node2);
directedGraph.addNode(node3);
Edge edge12=graphModel.factory().newEdge(node1, node2);
Edge edge21=graphModel.factory().newEdge(node2, node1);
Edge edge23=graphModel.factory().newEdge(node2, node3);
Edge edge32=graphModel.factory().newEdge(node3, node2);