List<GraphvizNode> nodes = graph.getGraphvizNodes();
String[] nodeNames = new String[nodes.size()];
for (int i = 0; i < nodeNames.length; i++) {
GraphvizNode gNode = nodes.get(i);
nodeNames[i] = gNode.getId() + " [label=\"" + gNode.getLabel() +
"\" color=\"" + gNode.getColor() + "\"]";
}
// We sort the nodes so we get a deterministic output every time regardless
// of the implementation of the graph data structure.
Arrays.sort(nodeNames);