Sort the lines of the graph when printing it for debug purposes, so t…

…hat random hash ordering doesn't cause the graph to have a different output

src/edu/stanford/nlp/graph/DirectedMultiGraph.java

@@ -664,17 +664,30 @@ public String toString() {
  StringBuilder s = new StringBuilder();
  s.append("{\n");
  s.append("Vertices:\n");
+
+ List<String> lines = new ArrayList<>();
  for (V vertex : outgoingEdges.keySet()) {
- s.append(" ").append(vertex).append('\n');
+ lines.add(" " + vertex + '\n');
+ }
+ Collections.sort(lines);
+ for (String line : lines) {
+ s.append(line);
  }
+
  s.append("Edges:\n");
+ lines = new ArrayList<>();
  for (V source : outgoingEdges.keySet()) {
  for (V dest : outgoingEdges.get(source).keySet()) {
  for (E edge : outgoingEdges.get(source).get(dest)) {
- s.append(" ").append(source).append(" -> ").append(dest).append(" : ").append(edge).append('\n');
+ lines.add(" " + source + " -> " + dest + " : " + edge + "\n");
  }
  }
  }
+ Collections.sort(lines);
+ for (String line : lines) {
+ s.append(line);
+ }
+
  s.append('}');
  return s.toString();
  }