public void setStrongDependents(Collection<T> deps) {
strongDependents = new LinkedList<T>(deps);
strongBackDependents = new LinkedList<T>();
for (T dependent : strongDependents) {
if (dependent.id < id) strongBackDependents.add(dependent);
}
Set<T> nonStrongDependents = HashSetFactory.make(dependents);
nonStrongDependents.removeAll(strongDependents);
this.nonStrongDependents = new LinkedList<T>(nonStrongDependents);
}
public static <T extends GraphNode<T>> Collection<Collection<T>> getConnectedComponents(
Set<T> constraints) {
Collection<T> unvisited = HashSetFactory.make();
for (T constraint : constraints) {
unvisited.add(constraint);
}
// DFS of the constraints graph
LinkedList<T> rPostorder = new LinkedList<T>();
while (!unvisited.isEmpty()) {
Iterator<T> it = unvisited.iterator();
T constraint = it.next();
DFS(constraint, unvisited, rPostorder, false);
}
// Set nodes numbering in reverse postorder
int id = 0;
for (Iterator<T> it = rPostorder.iterator(); it.hasNext(); id++) {
T node = it.next();
node.id = id;
}
// DFS of the transpose graph in reverse postorder
LinkedList<Collection<T>> components = new LinkedList<Collection<T>>();
while (!rPostorder.isEmpty()) {
LinkedList<T> temp = new LinkedList<T>();
T constraint = rPostorder.removeFirst();
DFS(constraint, rPostorder, temp, true);
SortedSet<T> component = new TreeSet<T>();
component.addAll(temp);
for (Iterator<T> it = component.iterator(); it.hasNext(); ) {
constraint = it.next();
SortedSet<T> tempSet = new TreeSet<T>();
for (Iterator<T> itDeps = constraint.dependents.iterator(); itDeps.hasNext(); ) {
T dependent = itDeps.next();
if (component.contains(dependent)) {
tempSet.add(dependent);
// constraint.strongDependents.add(dependent);
}
}
constraint.setStrongDependents(tempSet);
}
components.add(new LinkedList<T>(component));
}
return components;
}
public class GraphNode<T extends GraphNode<T>> implements Identifiable, Comparable<T> {
Set<T> dependents = HashSetFactory.make();
Set<T> dependsOn = HashSetFactory.make();
Collection<T> strongDependents = java.util.Collections.emptyList();
Collection<T> strongBackDependents = java.util.Collections.emptyList();
Collection<T> nonStrongDependents = java.util.Collections.emptyList();
int id;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public int compareTo(T other) {
return id - other.id;
}
public void setStrongDependents(Collection<T> deps) {
strongDependents = new LinkedList<T>(deps);
strongBackDependents = new LinkedList<T>();
for (T dependent : strongDependents) {
if (dependent.id < id) strongBackDependents.add(dependent);
}
Set<T> nonStrongDependents = HashSetFactory.make(dependents);
nonStrongDependents.removeAll(strongDependents);
this.nonStrongDependents = new LinkedList<T>(nonStrongDependents);
}
public static <T extends GraphNode<T>> void DFS(
T node, Collection<T> unvisited, LinkedList<T> rPostorder, boolean reverse) {
Iterator<T> it;
if (reverse) it = node.dependsOn.iterator();
else it = node.dependents.iterator();
unvisited.remove(node);
for (; it.hasNext(); ) {
T u = it.next();
if (unvisited.contains(u)) {
DFS(u, unvisited, rPostorder, reverse);
}
}
rPostorder.addFirst(node);
}
public static <T extends GraphNode<T>> Collection<Collection<T>> getConnectedComponents(
Set<T> constraints) {
Collection<T> unvisited = HashSetFactory.make();
for (T constraint : constraints) {
unvisited.add(constraint);
}
// DFS of the constraints graph
LinkedList<T> rPostorder = new LinkedList<T>();
while (!unvisited.isEmpty()) {
Iterator<T> it = unvisited.iterator();
T constraint = it.next();
DFS(constraint, unvisited, rPostorder, false);
}
// Set nodes numbering in reverse postorder
int id = 0;
for (Iterator<T> it = rPostorder.iterator(); it.hasNext(); id++) {
T node = it.next();
node.id = id;
}
// DFS of the transpose graph in reverse postorder
LinkedList<Collection<T>> components = new LinkedList<Collection<T>>();
while (!rPostorder.isEmpty()) {
LinkedList<T> temp = new LinkedList<T>();
T constraint = rPostorder.removeFirst();
DFS(constraint, rPostorder, temp, true);
SortedSet<T> component = new TreeSet<T>();
component.addAll(temp);
for (Iterator<T> it = component.iterator(); it.hasNext(); ) {
constraint = it.next();
SortedSet<T> tempSet = new TreeSet<T>();
for (Iterator<T> itDeps = constraint.dependents.iterator(); itDeps.hasNext(); ) {
T dependent = itDeps.next();
if (component.contains(dependent)) {
tempSet.add(dependent);
// constraint.strongDependents.add(dependent);
}
}
constraint.setStrongDependents(tempSet);
}
components.add(new LinkedList<T>(component));
}
return components;
}
}
