List<GraphvizEdge> edges = graph.getGraphvizEdges();
String[] edgeNames = new String[edges.size()];
for (int i = 0; i < edgeNames.length; i++) {
GraphvizEdge edge = edges.get(i);
edgeNames[i] = edge.getNode1Id() + edgeSymbol + edge.getNode2Id();
}
// Again, we sort the edges as well.
Arrays.sort(edgeNames);