Java tutorial
/* * Symphony - A modern community (forum/SNS/blog) platform written in Java. * Copyright (C) 2012-2016, b3log.org & hacpai.com * * This program 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 version 3 of the License, or * (at your option) any later version. * * This program 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 this program. If not, see <http://www.gnu.org/licenses/>. */ package org.b3log.symphony.processor.channel; import java.util.Collections; import java.util.Iterator; import java.util.Set; import java.util.concurrent.ConcurrentHashMap; 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.b3log.latke.logging.Logger; import org.b3log.symphony.model.Common; import org.json.JSONObject; /** * Char room channel. * * @author <a href="http://88250.b3log.org">Liang Ding</a> * @version 1.0.1.1, Apr 25, 2016 * @since 1.4.0 */ @ServerEndpoint(value = "/chat-room-channel", configurator = Channels.WebSocketConfigurator.class) public class ChatRoomChannel { /** * Logger. */ private static final Logger LOGGER = Logger.getLogger(ChatRoomChannel.class.getName()); /** * Session set. */ public static final Set<Session> SESSIONS = Collections.newSetFromMap(new ConcurrentHashMap()); /** * Called when the socket connection with the browser is established. * * @param session session */ @OnOpen public void onConnect(final Session session) { SESSIONS.add(session); synchronized (SESSIONS) { final Iterator<Session> i = SESSIONS.iterator(); while (i.hasNext()) { final Session s = i.next(); if (s.isOpen()) { final String msgStr = new JSONObject().put(Common.ONLINE_CHAT_CNT, SESSIONS.size()) .put(Common.TYPE, "online").toString(); s.getAsyncRemote().sendText(msgStr); } } } } /** * Called when the connection closed. * * @param session session * @param closeReason close reason */ @OnClose public void onClose(final Session session, final CloseReason closeReason) { removeSession(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) { removeSession(session); } /** * Notifies the specified chat message to browsers. * * @param message the specified message, for example <pre> * { * "userName": "", * "content": "" * } * </pre> */ public static void notifyChat(final JSONObject message) { message.put(Common.TYPE, "msg"); final String msgStr = message.toString(); synchronized (SESSIONS) { final Iterator<Session> i = SESSIONS.iterator(); while (i.hasNext()) { final Session session = i.next(); if (session.isOpen()) { session.getAsyncRemote().sendText(msgStr); } } } } /** * Removes the specified session. * * @param session the specified session */ private void removeSession(final Session session) { SESSIONS.remove(session); synchronized (SESSIONS) { final Iterator<Session> i = SESSIONS.iterator(); while (i.hasNext()) { final Session s = i.next(); if (s.isOpen()) { final String msgStr = new JSONObject().put(Common.ONLINE_CHAT_CNT, SESSIONS.size()) .put(Common.TYPE, "online").toString(); s.getAsyncRemote().sendText(msgStr); } } } } }