model.addNode(this, n2, root);
model.addNode(this, n3, root);
model.addNode(this, n4, root);
model.addNode(this, n5, root);
Edge e1 = model.createEdge("e1");
Edge e2 = model.createEdge("e2");
Edge e3 = model.createEdge("e3");
Edge e4 = model.createEdge("e4");
Edge e5 = model.createEdge("e5");
model.connectEdge(this, e1, s0, n1);
model.connectEdge(this, e2, s0, n2);
model.connectEdge(this, e3, s0, n3);
model.connectEdge(this, e4, s0, n4);
model.connectEdge(this, e5, s0, n5);
// another cluster
ArrayList set1 = new ArrayList();
Object o11 = Integer.valueOf(15);
Object o12 = Integer.valueOf(15);
Node s1 = model.createNode(set1);
Node n11 = model.createNode(o11);
Node n12 = model.createNode(o12);
model.addNode(this, s1, root);
model.addNode(this, n11, root);
model.addNode(this, n12, root);
Edge e6 = model.createEdge("e6");
Edge e7 = model.createEdge("e7");
model.connectEdge(this, e6, s1, n11);
model.connectEdge(this, e7, s1, n12);
// an empty cluster
ArrayList set2 = new ArrayList();