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Panda Nets is a client side library of many basic Internet protocols.

There is a newer version: 1.8.0

package panda.net.nntp;

/**
 * A placeholder utility class, used for constructing a tree of Threadables Original implementation
 * by Jamie Zawinski. See the Grendel source for more details here Threadable objects
 */
class ThreadContainer {
	Threadable threadable;
	ThreadContainer parent;
	// ThreadContainer prev;
	ThreadContainer next;
	ThreadContainer child;

	/**
	 * @param container
	 * @return true if child is under self's tree. Detects circular references
	 */
	boolean findChild(ThreadContainer target) {
		if (child == null) {
			return false;
		}
		else if (child == target) {
			return true;
		}
		else {
			return child.findChild(target);
		}
	}

	// Copy the ThreadContainer tree structure down into the underlying Threadable objects
	// (Make the Threadable tree look like the ThreadContainer tree)
	// TODO convert this to an iterative function - this can blow the stack
	// with very large Threadable trees
	void flush() {
		if (parent != null && threadable == null) {
			throw new RuntimeException("no threadable in " + this.toString());
		}

		parent = null;

		if (threadable != null) {
			threadable.setChild(child == null ? null : child.threadable);
		}

		if (child != null) {
			child.flush();
			child = null;
		}

		if (threadable != null) {
			threadable.setNext(next == null ? null : next.threadable);
		}

		if (next != null) {
			next.flush();
			next = null;
		}

		threadable = null;
	}

	/**
	 * Reverse the entire set of children
	 */
	void reverseChildren() {
		if (child != null) {
			ThreadContainer kid, prev, rest;
			for (prev = null, kid = child, rest = kid.next; kid != null; prev = kid, kid = rest, rest = (rest == null ? null : rest.next)) {
				kid.next = prev;
			}

			child = prev;

			// Do it for the kids
			for (kid = child; kid != null; kid = kid.next) {
				kid.reverseChildren();
			}
		}
	}
}