/**
* Reorganizes the tree by applying the rules to the tree from the changed node and returns a node
* that was top most of the flipped ones.
*/
protected Node<Payload> reorganizeForRecursion(final Node<Payload> changedNode) {
// rule a: if parent is marked already, do not mark the child
if (applyRuleA && isParentMarked(changedNode)) {
changedNode.getPayload().setMarked(false);
return changedNode.getParent();
}
// rule b: if this parent's all children are marked, mark parent, unmark children
if (applyRuleB && isParentAllChildMarkedForRuleB(changedNode)) {
changedNode.getParent().getPayload().setMarked(true);
for (Node<Payload> child : changedNode.getParent().getChildren()) {
child.getPayload().setMarked(false);
}
return changedNode.getParent();
}
return changedNode;
}
/**
* Returns true if parent exists (passed in node is not ROOT), and if parent {@link
* Payload#isMarked()} returns {@code true}.
*/
protected boolean isParentMarked(final Node<Payload> node) {
final Node<Payload> parent = node.getParent();
if (parent != null) {
if (parent.getPayload().isMarked()) {
return true;
} else {
return isParentMarked(parent);
}
} else {
return false;
}
}
/**
* Returns true if parent exists (passed in node is not ROOT), and parent's all children are
* marked (their {@link Payload#isMarked()} is {@code true} for all of them.
*/
protected boolean isParentAllChildMarkedForRuleB(final Node<Payload> node) {
final Node<Payload> parent = node.getParent();
if (parent != null) {
final List<Node<Payload>> children = parent.getChildren();
if (children.size() < 2) {
return false;
}
for (Node<Payload> child : children) {
if (!child.getPayload().isMarked()) {
return false;
}
}
return true;
} else {
return false;
}
}