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1   /************************************************************************
2    * Copyright (c) 1999-2006 The Apache Software Foundation.             *
3    * All rights reserved.                                                *
4    * ------------------------------------------------------------------- *
5    * Licensed under the Apache License, Version 2.0 (the "License"); you *
6    * may not use this file except in compliance with the License. You    *
7    * may obtain a copy of the License at:                                *
8    *                                                                     *
9    *     http://www.apache.org/licenses/LICENSE-2.0                      *
10   *                                                                     *
11   * Unless required by applicable law or agreed to in writing, software *
12   * distributed under the License is distributed on an "AS IS" BASIS,   *
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or     *
14   * implied.  See the License for the specific language governing       *
15   * permissions and limitations under the License.                      *
16   ***********************************************************************/
17  
18  package org.apache.james.pop3server;
19  
20  import org.apache.avalon.cornerstone.services.connection.ConnectionHandler;
21  import org.apache.avalon.excalibur.pool.DefaultPool;
22  import org.apache.avalon.excalibur.pool.HardResourceLimitingPool;
23  import org.apache.avalon.excalibur.pool.ObjectFactory;
24  import org.apache.avalon.excalibur.pool.Pool;
25  import org.apache.avalon.excalibur.pool.Poolable;
26  import org.apache.avalon.framework.activity.Initializable;
27  import org.apache.avalon.framework.configuration.Configuration;
28  import org.apache.avalon.framework.configuration.ConfigurationException;
29  import org.apache.avalon.framework.service.ServiceException;
30  import org.apache.avalon.framework.service.ServiceManager;
31  import org.apache.avalon.framework.logger.LogEnabled;
32  
33  import org.apache.james.core.AbstractJamesService;
34  import org.apache.james.services.MailServer;
35  import org.apache.james.services.UsersRepository;
36  import org.apache.james.util.watchdog.Watchdog;
37  import org.apache.james.util.watchdog.WatchdogFactory;
38  
39  /***
40   * <p>Accepts POP3 connections on a server socket and dispatches them to POP3Handlers.</p>
41   *
42   * <p>Also responsible for loading and parsing POP3 specific configuration.</p>
43   *
44   * @version 1.0.0, 24/04/1999
45   */
46  public class POP3Server extends AbstractJamesService implements POP3ServerMBean {
47  
48      /***
49       * The internal mail server service
50       */
51      private MailServer mailServer;
52  
53      /***
54       * The user repository for this server - used to authenticate users.
55       */
56      private UsersRepository users;
57  
58      /***
59       * The number of bytes to read before resetting
60       * the connection timeout timer.  Defaults to
61       * 20 KB.
62       */
63      private int lengthReset = 20 * 1024;
64  
65      /***
66       * The pool used to provide POP3 Handler objects
67       */
68      private Pool theHandlerPool = null;
69  
70      /***
71       * The factory used to provide POP3 Handler objects
72       */
73      private ObjectFactory theHandlerFactory = new POP3HandlerFactory();
74  
75      /***
76       * The factory used to generate Watchdog objects
77       */
78      private WatchdogFactory theWatchdogFactory;
79  
80      /***
81       * The configuration data to be passed to the handler
82       */
83      private POP3HandlerConfigurationData theConfigData
84          = new POP3HandlerConfigurationDataImpl();
85  
86      /***
87       * @see org.apache.avalon.framework.service.Serviceable#compose(ServiceManager)
88       */
89      public void service( final ServiceManager componentManager )
90          throws ServiceException {
91          super.service(componentManager);
92          mailServer = (MailServer)componentManager.lookup( MailServer.ROLE );
93          users = (UsersRepository)componentManager.lookup( UsersRepository.ROLE );
94      }
95  
96      /***
97       * @see org.apache.avalon.framework.configuration.Configurable#configure(Configuration)
98       */
99      public void configure(final Configuration configuration) throws ConfigurationException {
100         super.configure(configuration);
101         if (isEnabled()) {
102             Configuration handlerConfiguration = configuration.getChild("handler");
103             lengthReset = handlerConfiguration.getChild("lengthReset").getValueAsInteger(lengthReset);
104             if (getLogger().isInfoEnabled()) {
105                 getLogger().info("The idle timeout will be reset every " + lengthReset + " bytes.");
106             }
107         }
108     }
109 
110     /***
111      * @see org.apache.avalon.framework.activity.Initializable#initialize()
112      */
113     public void initialize() throws Exception {
114         super.initialize();
115         if (!isEnabled()) {
116             return;
117         }
118 
119         if (connectionLimit != null) {
120             theHandlerPool = new HardResourceLimitingPool(theHandlerFactory, 5, connectionLimit.intValue());
121             getLogger().debug("Using a bounded pool for POP3 handlers with upper limit " + connectionLimit.intValue());
122         } else {
123             // NOTE: The maximum here is not a real maximum.  The handler pool will continue to
124             //       provide handlers beyond this value.
125             theHandlerPool = new DefaultPool(theHandlerFactory, null, 5, 30);
126             getLogger().debug("Using an unbounded pool for POP3 handlers.");
127         }
128         if (theHandlerPool instanceof LogEnabled) {
129             ((LogEnabled)theHandlerPool).enableLogging(getLogger());
130         }
131         if (theHandlerPool instanceof Initializable) {
132             ((Initializable)theHandlerPool).initialize();
133         }
134 
135         theWatchdogFactory = getWatchdogFactory();
136     }
137 
138     /***
139      * @see org.apache.james.core.AbstractJamesService#getDefaultPort()
140      */
141      protected int getDefaultPort() {
142         return 110;
143      }
144 
145     /***
146      * @see org.apache.james.core.AbstractJamesService#getServiceType()
147      */
148     public String getServiceType() {
149         return "POP3 Service";
150     }
151 
152     /***
153      * @see org.apache.avalon.cornerstone.services.connection.AbstractHandlerFactory#newHandler()
154      */
155     protected ConnectionHandler newHandler()
156             throws Exception {
157         POP3Handler theHandler = (POP3Handler)theHandlerPool.get();
158 
159         Watchdog theWatchdog = theWatchdogFactory.getWatchdog(theHandler.getWatchdogTarget());
160 
161         theHandler.setConfigurationData(theConfigData);
162 
163         theHandler.setWatchdog(theWatchdog);
164 
165         return theHandler;
166     }
167 
168     /***
169      * @see org.apache.avalon.cornerstone.services.connection.ConnectionHandlerFactory#releaseConnectionHandler(ConnectionHandler)
170      */
171     public void releaseConnectionHandler( ConnectionHandler connectionHandler ) {
172         if (!(connectionHandler instanceof POP3Handler)) {
173             throw new IllegalArgumentException("Attempted to return non-POP3Handler to pool.");
174         }
175         theHandlerPool.put((Poolable)connectionHandler);
176     }
177 
178     /***
179      * The factory for producing handlers.
180      */
181     private static class POP3HandlerFactory
182         implements ObjectFactory {
183 
184         /***
185          * @see org.apache.avalon.excalibur.pool.ObjectFactory#newInstance()
186          */
187         public Object newInstance() throws Exception {
188             return new POP3Handler();
189         }
190 
191         /***
192          * @see org.apache.avalon.excalibur.pool.ObjectFactory#getCreatedClass()
193          */
194         public Class getCreatedClass() {
195             return POP3Handler.class;
196         }
197 
198         /***
199          * @see org.apache.avalon.excalibur.pool.ObjectFactory#decommision(Object)
200          */
201         public void decommission( Object object ) throws Exception {
202             return;
203         }
204     }
205 
206     /***
207      * A class to provide POP3 handler configuration to the handlers
208      */
209     private class POP3HandlerConfigurationDataImpl
210         implements POP3HandlerConfigurationData {
211 
212         /***
213          * @see org.apache.james.pop3server.POP3HandlerConfigurationData#getHelloName()
214          */
215         public String getHelloName() {
216             return POP3Server.this.helloName;
217         }
218 
219         /***
220          * @see org.apache.james.pop3server.POP3HandlerConfigurationData#getResetLength()
221          */
222         public int getResetLength() {
223             return POP3Server.this.lengthReset;
224         }
225 
226         /***
227          * @see org.apache.james.pop3server.POP3HandlerConfigurationData#getMailServer()
228          */
229         public MailServer getMailServer() {
230             return POP3Server.this.mailServer;
231         }
232 
233         /***
234          * @see org.apache.james.pop3server.POP3HandlerConfigurationData#getUsersRepository()
235          */
236         public UsersRepository getUsersRepository() {
237             return POP3Server.this.users;
238         }
239     }
240 }