/**
* Travel dependencies tree by DFS and Post-Order algorithm.
*
* @param tree The initial tree which contains root node only.
* @param footprint The footprint of the traversal.
* @param output Output queue of combined files.
*/
private void travel(
Stack<ArrayList<String>> tree, Stack<String> footprint, ArrayList<String> output) {
for (String node : tree.peek()) {
// Detect circular dependences by looking back footprint.
if (footprint.contains(node)) {
String msg = "Circular dependences was found\n";
for (String path : footprint) {
msg += " " + path + " ->\n";
}
msg += " " + node;
App.exit(msg);
}
// Skip visited node.
if (output.contains(node)) {
continue;
}
// Move forward.
footprint.push(node);
// Add sub nodes.
tree.push(getDependencies(node));
// Travel sub nodes.
travel(tree, footprint, output);
// Clean visited nodes.
tree.pop();
// Move backward.
footprint.pop();
// Add first visited node to output queue.
output.add(node);
}
}
