Node node5 = graphModel.factory().newNode("4");
directedGraph.addNode(node1);
directedGraph.addNode(node2);
directedGraph.addNode(node3);
directedGraph.addNode(node4);
directedGraph.addNode(node5);
Edge edge13 = graphModel.factory().newEdge(node1, node3);
Edge edge32 = graphModel.factory().newEdge(node3, node2);
Edge edge21 = graphModel.factory().newEdge(node2, node1);
Edge edge34 = graphModel.factory().newEdge(node3, node4);
Edge edge45 = graphModel.factory().newEdge(node4, node5);