public static Digraph merge(Digraph destination, DigraphIteration graphToMerge) {
for (Iterator i = graphToMerge.vertexIterator(); i.hasNext(); ) {
destination.addVertex(i.next());
}
for (ArcIterator i = graphToMerge.arcIterator(); i.hasNext(); ) {
Object arc = i.next();
Object origin = i.getOrigin();
Object dst = i.getDestination();
destination.putArc(origin, dst, arc);
}
return destination;
}
public static List findCycles(DigraphIteration graph) {
ArrayStack stack = new ArrayStack();
ArrayStack path = new ArrayStack();
Set seen = new HashSet();
List cycles = new ArrayList();
Iterator vertexIterator = graph.vertexIterator();
while (vertexIterator.hasNext()) {
while (vertexIterator.hasNext()) {
Object vertex = vertexIterator.next();
if (seen.add(vertex)) {
stack.push(graph.outgoingIterator(vertex));
path.push(vertex);
break;
}
}
while (!stack.isEmpty()) {
ArcIterator i = (ArcIterator) stack.peek();
Object origin = i.getOrigin();
boolean subtreeIsTraversed = true;
while (i.hasNext()) {
i.next();
Object dst = i.getDestination();
int index = path.indexOf(dst);
if (index < 0) {
seen.add(dst);
stack.push(graph.outgoingIterator(dst));
path.push(dst);
subtreeIsTraversed = false;
break;
} else {
cycles.add(new ArrayList(path.subList(index, path.size())));
}
}
if (subtreeIsTraversed) {
stack.pop();
path.pop();
}
}
}
return cycles;
}
public static Digraph transform(
Digraph result,
DigraphIteration source,
Transformer vertexTransform,
Transformer arcTransform) {
for (Iterator i = new TransformIterator(source.vertexIterator(), vertexTransform);
i.hasNext(); ) {
result.addVertex(i.next());
}
for (ArcIterator i =
new TransformArcIterator(source.arcIterator(), vertexTransform, arcTransform);
i.hasNext(); ) {
Object arc = i.next();
Object origin = i.getOrigin();
Object dst = i.getDestination();
result.putArc(origin, dst, arc);
}
return result;
}