/*

 * Copyright (c) 2009, 2010, 2011, 2012, B3log Team

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package org.b3log.solo.util.comparator;



import java.util.Comparator;

import java.util.Date;

import org.b3log.solo.model.Article;

import org.json.JSONObject;



/**

 * Article comparator by update date.

 *

 * @author <a href="mailto:DL88250@gmail.com">Liang Ding</a>

 * @version 1.0.0.1, Dec 30, 2010

 */

public final class ArticleUpdateDateComparator

        implements Comparator<JSONObject> {



    /**

     * Package default constructor.

     */

    ArticleUpdateDateComparator() {

    }



    @Override

    public int compare(final JSONObject article1, final JSONObject article2) {

        try {

            final Date date1 = (Date) article1.get(Article.ARTICLE_UPDATE_DATE);

            final Date date2 = (Date) article2.get(Article.ARTICLE_UPDATE_DATE);



            return date2.compareTo(date1);

        } catch (final Exception e) {

            throw new IllegalStateException(e);

        }

    }

}