messagegovernor.java

来自「Jive是基于JSP/JAVA技术构架的一个大型BBS论坛系统,这是Jive论坛」· Java 代码 · 共 79 行

/**
 * $RCSfile: MessageGovernor.java,v $
 * $Revision: 1.2 $
 * $Date: 2002/07/16 00:11:06 $
 *
 * Copyright (C) 1999-2001 CoolServlets, Inc. All rights reserved.
 *
 * This software is the proprietary information of CoolServlets, Inc.
 * Use is subject to license terms.
 */

package com.jivesoftware.forum.util;

import com.jivesoftware.forum.*;
import com.jivesoftware.util.*;

/**
 * Provides a mechanism to limit the rate at which a user may post messages. The Jive property
 * <tt>postRateInterval</tt> is the number of seconds that must elapse before a user is allowed
 * to post a message again. The default value is 30 seconds.<p>
 *
 * @author Matt Tucker
 */
public class MessageGovernor {

    private static long postInterval = 30*JiveGlobals.SECOND;

    static {
        String interval = JiveGlobals.getJiveProperty("postRateInterval");
        if (interval != null) {
            try {
                postInterval = Long.parseLong(interval) * JiveGlobals.SECOND;
            }
            catch (NumberFormatException nfe) {
                nfe.printStackTrace();
            }
        }
    }

    private static Cache postLimitCache = CacheFactory.createCache("postLimitCache", 2*1024,
            postInterval);

    /**
     * Returns true if the user should be allowed to post a new message and false otherwise. A user
     * is allowed to post a new message if the post interval has elapsed since the last post.
     * If false is returned, the user should be presented with a message to try their post again
     * after a short wait.
     *
     * @param user the wishes to create a new message.
     * @return true if the post should be allowed and false if it shouldn't.
     */
    public static boolean attemptNewMessage(User user) {
        Long userID = new Long(user.getID());
        // Check the cache to see if it contains an entry for the specified user. If it does,
        // then we know that the user shouldn't be allowed to make a post since the post
        // interval hasn't elapsed.
        if (postLimitCache.get(userID) != null) {
            return false;
        }
        // Otherwise, the user is allowed to make a post. Add an entry to the cache that will
        // expire after the post interval elapses so
        else {
            postLimitCache.put(userID, userID);
            return true;
        }
    }

    /**
     * Returns the length of time in seconds a user must wait before
     * posting a new message.
     *
     * @return the length of time in seconds a user must wait before posting
     * a new message.
     */
    public static int getPostInterval() {
        return (int)(postInterval/1000);
    }
}