menusequencecomparator.java

一个实用工具类

/*
 * Copyright (C) butor.com. All rights reserved.
 *
 * This software is published under the terms of the GNU Library General
 * Public License (GNU LGPL), a copy of which has been included with this
 * distribution in the LICENSE.txt file. 
 */


package org.butor.web.menu;

import org.butor.comparator.SortComparator;

/**
 * Comparator for menu based on field "sequence".
 *
 * @author Nguyen The Hung
 */
public class MenuSequenceComparator extends SortComparator {

	/**
	 * Constructor for MenuSequenceComparator.
	 */
	public MenuSequenceComparator() {
		super();
	}
	
	/**
	 * Compare two MenuItem objects. (Overriding the parent class method).
	 * @param o1 java.lang.Object
	 * @param o2 java.lang.Object
	 * @return int  
	 */
	public int compare(Object o1, Object o2) {
		return compareElements(o1, o2);
	}

	/**
	 * Compare two MenuItem objects.
	 * @param o1 java.lang.Object
	 * @param o2 java.lang.Object
	 * @return int
	 * Example : ASC & if o1 < o2  =>  <0
	 * 				 & if o1 = o2  =>   0
	 * 				 & if o1 > o2  =>  >0
	 */
	public int compareElements(Object o1, Object o2) {
		MenuItem node1 = (MenuItem) o1;
		MenuItem node2 = (MenuItem) o2;
		
		int dif = node1.getSequence() - node2.getSequence();
	
		if (f_order == SORT_ASC) {
			return dif;
		} else {
			return dif * -1;
		}
	}
}