UserManager.java

/*
 * Copyright 2007 Zhang, Zheng <oldbig@gmail.com>
 * 
 * This file is part of ZOJ.
 * 
 * ZOJ is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either revision 3 of the License, or (at your option) any later revision.
 * 
 * ZOJ 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 General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License along with ZOJ. if not, see
 * <http://www.gnu.org/licenses/>.
 */

package cn.edu.zju.acm.onlinejudge.util;

import cn.edu.zju.acm.onlinejudge.bean.UserProfile;
import cn.edu.zju.acm.onlinejudge.persistence.PersistenceCreationException;
import cn.edu.zju.acm.onlinejudge.persistence.PersistenceException;
import cn.edu.zju.acm.onlinejudge.persistence.UserPersistence;
import cn.edu.zju.acm.onlinejudge.util.cache.Cache;

public class UserManager {

    private final Cache<UserProfile> userCache;

    /**
     * UserManager.
     */
    private static UserManager instance = null;

    /**
     * <p>
     * Constructor of UserManager class.
     * </p>
     * 
     * @throws PersistenceCreationException
     * 
     */
    private UserManager() throws PersistenceCreationException {
        this.userCache = new Cache<UserProfile>(60000, 200);
    }

    /**
     * Gets the singleton instance.
     * 
     * @return the singleton instance.
     * @throws PersistenceCreationException
     */
    public static UserManager getInstance() throws PersistenceCreationException {
        if (UserManager.instance == null) {
            synchronized (UserManager.class) {
                if (UserManager.instance == null) {
                    UserManager.instance = new UserManager();
                }
            }
        }
        return UserManager.instance;
    }

    public UserProfile getUserProfile(long userId) throws PersistenceException {
        Object key = new Long(userId);
        synchronized (this.userCache) {
            UserProfile user = this.userCache.get(key);
            if (user == null) {
                UserPersistence userPersistence = PersistenceManager.getInstance().getUserPersistence();
                user = userPersistence.getUserProfile(userId);
                this.userCache.put(key, user);
            }
            return user;
        }
    }

    public void refresh(long userId) {

        Object key = new Long(userId);
        synchronized (this.userCache) {
            this.userCache.remove(key);
        }
    }

}