org/sonews/daemon/command/NextPrevCommand.java
author cli
Wed, 12 Aug 2009 13:03:23 +0200
changeset 7 0b76e099eb96
parent 3 2fdc9cc89502
child 20 6ae5e4f8329b
permissions -rw-r--r--
PullFeeder sends an addition "MODE READER" to peers.
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/*
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 *   SONEWS News Server
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 *   see AUTHORS for the list of contributors
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 *
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 *   This program is free software: you can redistribute it and/or modify
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 *   it under the terms of the GNU General Public License as published by
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 *   the Free Software Foundation, either version 3 of the License, or
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 *   (at your option) any later version.
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 *
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 *   This program is distributed in the hope that it will be useful,
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 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
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 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 *   GNU General Public License for more details.
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 *
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 *   You should have received a copy of the GNU General Public License
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 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
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 */
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package org.sonews.daemon.command;
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import java.io.IOException;
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import org.sonews.daemon.NNTPConnection;
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import org.sonews.storage.Article;
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import org.sonews.storage.Channel;
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import org.sonews.storage.StorageBackendException;
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/**
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 * Class handling the NEXT and LAST command.
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 * @author Christian Lins
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 * @author Dennis Schwerdel
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 * @since n3tpd/0.1
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 */
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public class NextPrevCommand implements Command
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{
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  @Override
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  public String[] getSupportedCommandStrings()
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  {
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    return new String[]{"NEXT", "PREV"};
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  }
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  @Override
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  public boolean hasFinished()
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  {
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    return true;
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  }
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  @Override
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  public boolean isStateful()
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  {
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    return false;
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  }
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  @Override
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  public void processLine(NNTPConnection conn, final String line, byte[] raw)
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    throws IOException, StorageBackendException
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  {
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    final Article currA = conn.getCurrentArticle();
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    final Channel currG = conn.getCurrentChannel();
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    if (currA == null)
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    {
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      conn.println("420 no current article has been selected");
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      return;
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    }
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    if (currG == null)
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    {
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      conn.println("412 no newsgroup selected");
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      return;
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    }
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    final String[] command = line.split(" ");
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    if(command[0].equalsIgnoreCase("NEXT"))
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    {
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      selectNewArticle(conn, currA, currG, 1);
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    }
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    else if(command[0].equalsIgnoreCase("PREV"))
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    {
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      selectNewArticle(conn, currA, currG, -1);
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    }
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    else
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    {
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      conn.println("500 internal server error");
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    }
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  }
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  private void selectNewArticle(NNTPConnection conn, Article article, Channel grp,
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    final int delta)
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    throws IOException, StorageBackendException
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  {
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    assert article != null;
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    article = grp.getArticle(grp.getIndexOf(article) + delta);
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    if(article == null)
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    {
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      conn.println("421 no next article in this group");
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    }
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    else
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    {
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      conn.setCurrentArticle(article);
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      conn.println("223 " + conn.getCurrentChannel().getIndexOf(article)
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                    + " " + article.getMessageID()
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                    + " article retrieved - request text separately");
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    }
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  }
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}