TreeNode.java

/*
 * Copyright 2013 Hannes Janetzek
 *
 * This file is part of the OpenScienceMap project (http://www.opensciencemap.org).
 *
 * This program is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */
package org.oscim.utils.quadtree;

public class TreeNode<T extends TreeNode<T, E>, E> {

	public T parent;

	/** top-left */
	public T child00;

	/** bottom-left */
	public T child01;

	/** top-right */
	public T child10;

	/** bottom-right */
	public T child11;

	/** payload */
	public E item;

	/** id of this child relative to parent */
	int id;

	/** number of children and grandchildren */
	int refs = 0;

	public E parent() {
		return parent.item;
	}

	public E child(int i) {
		switch (i) {
			case 0:
				return (child00 != null) ? child00.item : null;
			case 1:
				return (child01 != null) ? child01.item : null;
			case 2:
				return (child10 != null) ? child10.item : null;
			case 3:
				return (child11 != null) ? child11.item : null;
		}
		return null;
	}

	public boolean isRoot() {
		return this == parent;
	}

}