org/sonews/daemon/command/NextPrevCommand.java
author cli
Sat, 01 May 2010 14:27:30 +0200
changeset 28 15d14b110240
parent 20 6ae5e4f8329b
permissions -rw-r--r--
Make mailinglist gateway more reliable, probably.
     1 /*
     2  *   SONEWS News Server
     3  *   see AUTHORS for the list of contributors
     4  *
     5  *   This program is free software: you can redistribute it and/or modify
     6  *   it under the terms of the GNU General Public License as published by
     7  *   the Free Software Foundation, either version 3 of the License, or
     8  *   (at your option) any later version.
     9  *
    10  *   This program is distributed in the hope that it will be useful,
    11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
    12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    13  *   GNU General Public License for more details.
    14  *
    15  *   You should have received a copy of the GNU General Public License
    16  *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
    17  */
    18 
    19 package org.sonews.daemon.command;
    20 
    21 import java.io.IOException;
    22 import org.sonews.daemon.NNTPConnection;
    23 import org.sonews.storage.Article;
    24 import org.sonews.storage.Channel;
    25 import org.sonews.storage.StorageBackendException;
    26 
    27 /**
    28  * Class handling the NEXT and LAST command.
    29  * @author Christian Lins
    30  * @author Dennis Schwerdel
    31  * @since n3tpd/0.1
    32  */
    33 public class NextPrevCommand implements Command
    34 {
    35 
    36   @Override
    37   public String[] getSupportedCommandStrings()
    38   {
    39     return new String[]{"NEXT", "PREV"};
    40   }
    41 
    42   @Override
    43   public boolean hasFinished()
    44   {
    45     return true;
    46   }
    47 
    48   @Override
    49   public String impliedCapability()
    50   {
    51     return null;
    52   }
    53 
    54   @Override
    55   public boolean isStateful()
    56   {
    57     return false;
    58   }
    59 
    60   @Override
    61   public void processLine(NNTPConnection conn, final String line, byte[] raw)
    62     throws IOException, StorageBackendException
    63   {
    64     final Article currA = conn.getCurrentArticle();
    65     final Channel currG = conn.getCurrentChannel();
    66     
    67     if (currA == null)
    68     {
    69       conn.println("420 no current article has been selected");
    70       return;
    71     }
    72     
    73     if (currG == null)
    74     {
    75       conn.println("412 no newsgroup selected");
    76       return;
    77     }
    78     
    79     final String[] command = line.split(" ");
    80 
    81     if(command[0].equalsIgnoreCase("NEXT"))
    82     {
    83       selectNewArticle(conn, currA, currG, 1);
    84     }
    85     else if(command[0].equalsIgnoreCase("PREV"))
    86     {
    87       selectNewArticle(conn, currA, currG, -1);
    88     }
    89     else
    90     {
    91       conn.println("500 internal server error");
    92     }
    93   }
    94   
    95   private void selectNewArticle(NNTPConnection conn, Article article, Channel grp,
    96     final int delta)
    97     throws IOException, StorageBackendException
    98   {
    99     assert article != null;
   100 
   101     article = grp.getArticle(grp.getIndexOf(article) + delta);
   102 
   103     if(article == null)
   104     {
   105       conn.println("421 no next article in this group");
   106     }
   107     else
   108     {
   109       conn.setCurrentArticle(article);
   110       conn.println("223 " + conn.getCurrentChannel().getIndexOf(article)
   111                     + " " + article.getMessageID()
   112                     + " article retrieved - request text separately");
   113     }
   114   }
   115 
   116 }