/**
* Recursively assigns g_value for all nodes that could be reached from this node.
*
* @param val the value to assign to this node
* @param max the maximum value (= # of keywords)
*/
public void assignGValue(long val, int max) {
// check for valid input
if ((val < 0) || (val >= max)) {
System.err.println("Invalid g-value.");
}
// only change if not already assigned
if (this.gValue == -1) {
this.gValue = val;
Enumeration<Node> e = adjacency.keys();
while (e.hasMoreElements()) {
Node adj = e.nextElement();
val = (adjacency.get(adj).longValue() - this.gValue + max) % max;
adj.assignGValue(val, max);
}
}
}
/**
* Checks wheter there is a path from this node to the target node. Uses Depth First Search and
* marks visited nodes on the path
*
* @param target the target node
* @return true iff the target node is reachable
*/
public boolean reaches(Node target) {
if (target == this) {
return true;
} else {
// depth first search the adjacency list
setVisited(true);
Enumeration<Node> e = adjacency.keys();
while (e.hasMoreElements()) {
Node adj = e.nextElement();
if (!adj.getVisited()) {
if (adj.reaches(target)) {
return true;
}
}
}
return false;
}
}
