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1   /*
2    *  Licensed to the Apache Software Foundation (ASF) under one
3    *  or more contributor license agreements.  See the NOTICE file
4    *  distributed with this work for additional information
5    *  regarding copyright ownership.  The ASF licenses this file
6    *  to you under the Apache License, Version 2.0 (the
7    *  "License"); you may not use this file except in compliance
8    *  with the License.  You may obtain a copy of the License at
9    *  
10   *    http://www.apache.org/licenses/LICENSE-2.0
11   *  
12   *  Unless required by applicable law or agreed to in writing,
13   *  software distributed under the License is distributed on an
14   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   *  KIND, either express or implied.  See the License for the
16   *  specific language governing permissions and limitations
17   *  under the License. 
18   *  
19   */
20  package org.apache.mina.example.chat;
21  
22  import java.util.Collections;
23  import java.util.HashSet;
24  import java.util.Iterator;
25  import java.util.Set;
26  
27  import org.apache.mina.common.IoHandler;
28  import org.apache.mina.common.IoHandlerAdapter;
29  import org.apache.mina.common.IoSession;
30  import org.apache.mina.util.SessionLog;
31  
32  /**
33   * {@link IoHandler} implementation of a simple chat server protocol.
34   * 
35   * @author The Apache Directory Project (mina-dev@directory.apache.org)
36   * @version $Rev$, $Date$
37   */
38  public class ChatProtocolHandler extends IoHandlerAdapter {
39      private Set<IoSession> sessions = Collections
40              .synchronizedSet(new HashSet<IoSession>());
41  
42      private Set<String> users = Collections
43              .synchronizedSet(new HashSet<String>());
44  
45      public void exceptionCaught(IoSession session, Throwable cause) {
46          SessionLog.error(session, "", cause);
47          // Close connection when unexpected exception is caught.
48          session.close();
49      }
50  
51      public void messageReceived(IoSession session, Object message) {
52          String theMessage = (String) message;
53          String[] result = theMessage.split(" ", 2);
54          String theCommand = result[0];
55  
56          try {
57  
58              ChatCommand command = ChatCommand.valueOf(theCommand);
59              String user = (String) session.getAttribute("user");
60  
61              switch (command.toInt()) {
62  
63              case ChatCommand.QUIT:
64                  session.write("QUIT OK");
65                  session.close();
66                  break;
67              case ChatCommand.LOGIN:
68  
69                  if (user != null) {
70                      session.write("LOGIN ERROR user " + user
71                              + " already logged in.");
72                      return;
73                  }
74  
75                  if (result.length == 2) {
76                      user = result[1];
77                  } else {
78                      session.write("LOGIN ERROR invalid login command.");
79                      return;
80                  }
81  
82                  // check if the username is already used
83                  if (users.contains(user)) {
84                      session.write("LOGIN ERROR the name " + user
85                              + " is already used.");
86                      return;
87                  }
88  
89                  sessions.add(session);
90                  session.setAttribute("user", user);
91  
92                  // Allow all users
93                  users.add(user);
94                  session.write("LOGIN OK");
95                  broadcast("The user " + user + " has joined the chat session.");
96                  break;
97  
98              case ChatCommand.BROADCAST:
99  
100                 if (result.length == 2) {
101                     broadcast(user + ": " + result[1]);
102                 }
103                 break;
104             default:
105                 SessionLog.info(session, "Unhandled command: " + command);
106                 break;
107             }
108 
109         } catch (IllegalArgumentException e) {
110             SessionLog.debug(session, e.getMessage());
111         }
112     }
113 
114     public void broadcast(String message) {
115         synchronized (sessions) {
116             Iterator iter = sessions.iterator();
117             while (iter.hasNext()) {
118                 IoSession s = (IoSession) iter.next();
119                 if (s.isConnected()) {
120                     s.write("BROADCAST OK " + message);
121                 }
122             }
123         }
124     }
125 
126     public void sessionClosed(IoSession session) throws Exception {
127         String user = (String) session.getAttribute("user");
128         users.remove(user);
129         sessions.remove(session);
130         broadcast("The user " + user + " has left the chat session.");
131     }
132 
133     public boolean isChatUser(String name) {
134         return users.contains(name);
135     }
136 
137     public int getNumberOfUsers() {
138         return users.size();
139     }
140 
141     public void kick(String name) {
142         synchronized (sessions) {
143             Iterator iter = sessions.iterator();
144             while (iter.hasNext()) {
145                 IoSession s = (IoSession) iter.next();
146                 if (name.equals(s.getAttribute("user"))) {
147                     s.close();
148                     break;
149                 }
150             }
151         }
152     }
153 }