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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 }