org.b3log.symphony.processor.channel.ArticleListChannel.java Source code

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Here is the source code for org.b3log.symphony.processor.channel.ArticleListChannel.java

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/*
 * Copyright (c) 2012-2016, b3log.org & hacpai.com & fangstar.com
 *
 * 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.symphony.processor.channel;

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import javax.websocket.CloseReason;
import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.ServerEndpoint;
import org.apache.commons.lang.StringUtils;
import org.b3log.latke.logging.Logger;
import org.b3log.symphony.model.Article;
import org.json.JSONObject;

/**
 * Article list channel.
 *
 * @author <a href="http://88250.b3log.org">Liang Ding</a>
 * @version 2.0.1.1, Feb 28, 2016
 * @since 1.3.0
 */
@ServerEndpoint(value = "/article-list-channel", configurator = Channels.WebSocketConfigurator.class)
public class ArticleListChannel {

    /**
     * Logger.
     */
    private static final Logger LOGGER = Logger.getLogger(ArticleListChannel.class.getName());

    /**
     * Session articles &lt;session, "articleId1,articleId2"&gt;.
     */
    public static final Map<Session, String> SESSIONS = Collections.synchronizedMap(new HashMap<Session, String>());

    /**
     * Called when the socket connection with the browser is established.
     *
     * @param session session
     */
    @OnOpen
    public void onConnect(final Session session) {
        final String articleIds = (String) Channels.getHttpParameter(session, Article.ARTICLE_T_IDS);
        if (StringUtils.isBlank(articleIds)) {
            return;
        }

        SESSIONS.put(session, articleIds);
    }

    /**
     * Called when the connection closed.
     *
     * @param session session
     * @param closeReason close reason
     */
    @OnClose
    public void onClose(final Session session, final CloseReason closeReason) {
        SESSIONS.remove(session);
    }

    /**
     * Called when a message received from the browser.
     *
     * @param message message
     */
    @OnMessage
    public void onMessage(final String message) {
    }

    /**
     * Called in case of an error.
     *
     * @param session session
     * @param error error
     */
    @OnError
    public void onError(final Session session, final Throwable error) {
        SESSIONS.remove(session);
    }

    /**
     * Notifies the specified article heat message to browsers.
     *
     * @param message the specified message, for example      <pre>
     * {
     *     "articleId": "",
     *     "operation": "" // "+"/"-"
     * }
     * </pre>
     */
    public static void notifyHeat(final JSONObject message) {
        final String articleId = message.optString(Article.ARTICLE_T_ID);
        final String msgStr = message.toString();

        synchronized (SESSIONS) {
            for (final Map.Entry<Session, String> entry : SESSIONS.entrySet()) {
                final Session session = entry.getKey();
                final String articleIds = entry.getValue();

                if (!StringUtils.contains(articleIds, articleId)) {
                    continue;
                }

                if (session.isOpen()) {
                    session.getAsyncRemote().sendText(msgStr);
                }
            }
        }
    }
}