001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    
018    package org.apache.commons.net.pop3;
019    
020    import java.io.BufferedReader;
021    import java.io.BufferedWriter;
022    import java.io.EOFException;
023    import java.io.IOException;
024    import java.io.InputStreamReader;
025    import java.io.OutputStreamWriter;
026    import java.util.ArrayList;
027    import java.util.List;
028    
029    import org.apache.commons.net.MalformedServerReplyException;
030    import org.apache.commons.net.ProtocolCommandSupport;
031    import org.apache.commons.net.SocketClient;
032    import org.apache.commons.net.io.CRLFLineReader;
033    
034    /***
035     * The POP3 class is not meant to be used by itself and is provided
036     * only so that you may easily implement your own POP3 client if
037     * you so desire.  If you have no need to perform your own implementation,
038     * you should use {@link org.apache.commons.net.pop3.POP3Client}.
039     * <p>
040     * Rather than list it separately for each method, we mention here that
041     * every method communicating with the server and throwing an IOException
042     * can also throw a
043     * {@link org.apache.commons.net.MalformedServerReplyException}
044     * , which is a subclass
045     * of IOException.  A MalformedServerReplyException will be thrown when
046     * the reply received from the server deviates enough from the protocol
047     * specification that it cannot be interpreted in a useful manner despite
048     * attempts to be as lenient as possible.
049     * <p>
050     * <p>
051     * @see POP3Client
052     * @see org.apache.commons.net.MalformedServerReplyException
053     ***/
054    
055    public class POP3 extends SocketClient
056    {
057        /*** The default POP3 port.  Set to 110 according to RFC 1288. ***/
058        public static final int DEFAULT_PORT = 110;
059        /***
060         * A constant representing the state where the client is not yet connected
061         * to a POP3 server.
062         ***/
063        public static final int DISCONNECTED_STATE = -1;
064        /***  A constant representing the POP3 authorization state. ***/
065        public static final int AUTHORIZATION_STATE = 0;
066        /***  A constant representing the POP3 transaction state. ***/
067        public static final int TRANSACTION_STATE = 1;
068        /***  A constant representing the POP3 update state. ***/
069        public static final int UPDATE_STATE = 2;
070    
071        static final String _OK = "+OK";
072        // The reply indicating intermediate response to a command.
073        static final String _OK_INT = "+ ";
074        static final String _ERROR = "-ERR";
075    
076        // We have to ensure that the protocol communication is in ASCII
077        // but we use ISO-8859-1 just in case 8-bit characters cross
078        // the wire.
079        private static final String __DEFAULT_ENCODING = "ISO-8859-1";
080    
081        private int __popState;
082        private BufferedWriter __writer;
083    
084        BufferedReader _reader;
085        int _replyCode;
086        String _lastReplyLine;
087        List<String> _replyLines;
088    
089        /**
090         * A ProtocolCommandSupport object used to manage the registering of
091         * ProtocolCommandListeners and te firing of ProtocolCommandEvents.
092         */
093        protected ProtocolCommandSupport _commandSupport_;
094    
095        /***
096         * The default POP3Client constructor.  Initializes the state
097         * to <code>DISCONNECTED_STATE</code>.
098         ***/
099        public POP3()
100        {
101            setDefaultPort(DEFAULT_PORT);
102            __popState = DISCONNECTED_STATE;
103            _reader = null;
104            __writer = null;
105            _replyLines = new ArrayList<String>();
106            _commandSupport_ = new ProtocolCommandSupport(this);
107        }
108    
109        private void __getReply() throws IOException
110        {
111            String line;
112    
113            _replyLines.clear();
114            line = _reader.readLine();
115    
116            if (line == null)
117                throw new EOFException("Connection closed without indication.");
118    
119            if (line.startsWith(_OK))
120                _replyCode = POP3Reply.OK;
121            else if (line.startsWith(_ERROR))
122                _replyCode = POP3Reply.ERROR;
123            else if (line.startsWith(_OK_INT))
124                _replyCode = POP3Reply.OK_INT;
125            else
126                throw new
127                MalformedServerReplyException(
128                    "Received invalid POP3 protocol response from server." + line);
129    
130            _replyLines.add(line);
131            _lastReplyLine = line;
132    
133            fireReplyReceived(_replyCode, getReplyString());
134        }
135    
136    
137        /***
138         * Performs connection initialization and sets state to
139         * <code> AUTHORIZATION_STATE </code>.
140         ***/
141        @Override
142        protected void _connectAction_() throws IOException
143        {
144            super._connectAction_();
145            _reader =
146              new CRLFLineReader(new InputStreamReader(_input_,
147                                                       __DEFAULT_ENCODING));
148            __writer =
149              new BufferedWriter(new OutputStreamWriter(_output_,
150                                                        __DEFAULT_ENCODING));
151            __getReply();
152            setState(AUTHORIZATION_STATE);
153        }
154    
155    
156        /**
157         * Set the internal POP3 state.
158         * @param state the new state. This must be one of the <code>_STATE</code> constants.
159         */
160        public void setState(int state)
161        {
162            __popState = state;
163        }
164    
165    
166        /***
167         * Returns the current POP3 client state.
168         * <p>
169         * @return The current POP3 client state.
170         ***/
171        public int getState()
172        {
173            return __popState;
174        }
175    
176    
177        /***
178         * Retrieves the additional lines of a multi-line server reply.
179         ***/
180        public void getAdditionalReply() throws IOException
181        {
182            String line;
183    
184            line = _reader.readLine();
185            while (line != null)
186            {
187                _replyLines.add(line);
188                if (line.equals("."))
189                    break;
190                line = _reader.readLine();
191            }
192        }
193    
194    
195        /***
196         * Disconnects the client from the server, and sets the state to
197         * <code> DISCONNECTED_STATE </code>.  The reply text information
198         * from the last issued command is voided to allow garbage collection
199         * of the memory used to store that information.
200         * <p>
201         * @exception IOException  If there is an error in disconnecting.
202         ***/
203        @Override
204        public void disconnect() throws IOException
205        {
206            super.disconnect();
207            _reader = null;
208            __writer = null;
209            _lastReplyLine = null;
210            _replyLines.clear();
211            setState(DISCONNECTED_STATE);
212        }
213    
214    
215        /***
216         * Sends a command an arguments to the server and returns the reply code.
217         * <p>
218         * @param command  The POP3 command to send.
219         * @param args     The command arguments.
220         * @return  The server reply code (either POP3Reply.OK, POP3Reply.ERROR or POP3Reply.OK_INT).
221         ***/
222        public int sendCommand(String command, String args) throws IOException
223        {
224            if (__writer == null) {
225                throw new IllegalStateException("Socket is not connected");
226            }
227            StringBuilder __commandBuffer = new StringBuilder();
228            __commandBuffer.append(command);
229    
230            if (args != null)
231            {
232                __commandBuffer.append(' ');
233                __commandBuffer.append(args);
234            }
235            __commandBuffer.append(SocketClient.NETASCII_EOL);
236    
237            String message = __commandBuffer.toString();
238            __writer.write(message);
239            __writer.flush();
240    
241            fireCommandSent(command, message);
242    
243            __getReply();
244            return _replyCode;
245        }
246    
247        /***
248         * Sends a command with no arguments to the server and returns the
249         * reply code.
250         * <p>
251         * @param command  The POP3 command to send.
252         * @return  The server reply code (either POP3Reply.OK, POP3Reply.ERROR or POP3Reply.OK_INT).
253         ***/
254        public int sendCommand(String command) throws IOException
255        {
256            return sendCommand(command, null);
257        }
258    
259        /***
260         * Sends a command an arguments to the server and returns the reply code.
261         * <p>
262         * @param command  The POP3 command to send
263         *                  (one of the POP3Command constants).
264         * @param args     The command arguments.
265         * @return  The server reply code (either POP3Reply.OK, POP3Reply.ERROR or POP3Reply.OK_INT).
266         ***/
267        public int sendCommand(int command, String args) throws IOException
268        {
269            return sendCommand(POP3Command._commands[command], args);
270        }
271    
272        /***
273         * Sends a command with no arguments to the server and returns the
274         * reply code.
275         * <p>
276         * @param command  The POP3 command to send
277         *                  (one of the POP3Command constants).
278         * @return  The server reply code (either POP3Reply.OK, POP3Reply.ERROR or POP3Reply.OK_INT).
279         ***/
280        public int sendCommand(int command) throws IOException
281        {
282            return sendCommand(POP3Command._commands[command], null);
283        }
284    
285    
286        /***
287         * Returns an array of lines received as a reply to the last command
288         * sent to the server.  The lines have end of lines truncated.  If
289         * the reply is a single line, but its format ndicates it should be
290         * a multiline reply, then you must call
291         * {@link #getAdditionalReply  getAdditionalReply() } to
292         * fetch the rest of the reply, and then call <code>getReplyStrings</code>
293         * again.  You only have to worry about this if you are implementing
294         * your own client using the {@link #sendCommand  sendCommand } methods.
295         * <p>
296         * @return The last server response.
297         ***/
298        public String[] getReplyStrings()
299        {
300            return _replyLines.toArray(new String[_replyLines.size()]);
301        }
302    
303        /***
304         * Returns the reply to the last command sent to the server.
305         * The value is a single string containing all the reply lines including
306         * newlines.  If the reply is a single line, but its format ndicates it
307         * should be a multiline reply, then you must call
308         * {@link #getAdditionalReply  getAdditionalReply() } to
309         * fetch the rest of the reply, and then call <code>getReplyString</code>
310         * again.  You only have to worry about this if you are implementing
311         * your own client using the {@link #sendCommand  sendCommand } methods.
312         * <p>
313         * @return The last server response.
314         ***/
315        public String getReplyString()
316        {
317            StringBuilder buffer = new StringBuilder(256);
318    
319            for (String entry : _replyLines)
320            {
321                buffer.append(entry);
322                buffer.append(SocketClient.NETASCII_EOL);
323            }
324    
325            return buffer.toString();
326        }
327    
328        /**
329         * Removes a ProtocolCommandListener.
330         * 
331         * Delegates this incorrectly named method - removeProtocolCommandistener (note the missing "L")- to 
332         * the correct method {@link SocketClient#removeProtocolCommandListener}
333         * @param listener The ProtocolCommandListener to remove
334         */
335        public void removeProtocolCommandistener(org.apache.commons.net.ProtocolCommandListener listener){
336            removeProtocolCommandListener(listener);
337        }
338    
339        /**
340         * Provide command support to super-class
341         */
342        @Override
343        protected ProtocolCommandSupport getCommandSupport() {
344            return _commandSupport_;
345        }
346    }
347