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