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: 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;
cli@48: import org.sonews.storage.Group;
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:  */
cli@48: public class NextPrevCommand implements Command {
chris@1: 
cli@37: 	@Override
cli@48: 	public String[] getSupportedCommandStrings() {
cli@48: 		return new String[]{"NEXT", "PREV"};
cli@37: 	}
chris@1: 
cli@37: 	@Override
cli@48: 	public boolean hasFinished() {
cli@37: 		return true;
cli@37: 	}
chris@1: 
cli@37: 	@Override
cli@48: 	public String impliedCapability() {
cli@37: 		return null;
cli@37: 	}
cli@20: 
cli@37: 	@Override
cli@48: 	public boolean isStateful() {
cli@37: 		return false;
cli@37: 	}
chris@3: 
cli@37: 	@Override
cli@37: 	public void processLine(NNTPConnection conn, final String line, byte[] raw)
cli@48: 			throws IOException, StorageBackendException {
cli@37: 		final Article currA = conn.getCurrentArticle();
cli@48: 		final Group currG = conn.getCurrentChannel();
chris@1: 
cli@37: 		if (currA == null) {
cli@37: 			conn.println("420 no current article has been selected");
cli@37: 			return;
cli@37: 		}
chris@1: 
cli@37: 		if (currG == null) {
cli@37: 			conn.println("412 no newsgroup selected");
cli@37: 			return;
cli@37: 		}
chris@1: 
cli@37: 		final String[] command = line.split(" ");
chris@1: 
cli@37: 		if (command[0].equalsIgnoreCase("NEXT")) {
cli@37: 			selectNewArticle(conn, currA, currG, 1);
cli@37: 		} else if (command[0].equalsIgnoreCase("PREV")) {
cli@37: 			selectNewArticle(conn, currA, currG, -1);
cli@37: 		} else {
cli@37: 			conn.println("500 internal server error");
cli@37: 		}
cli@37: 	}
cli@37: 
cli@48: 	private void selectNewArticle(NNTPConnection conn, Article article, Group grp,
cli@48: 			final int delta)
cli@48: 			throws IOException, StorageBackendException {
cli@37: 		assert article != null;
cli@37: 
cli@37: 		article = grp.getArticle(grp.getIndexOf(article) + delta);
cli@37: 
cli@37: 		if (article == null) {
cli@37: 			conn.println("421 no next article in this group");
cli@37: 		} else {
cli@37: 			conn.setCurrentArticle(article);
cli@37: 			conn.println("223 " + conn.getCurrentChannel().getIndexOf(article)
cli@48: 					+ " " + article.getMessageID()
cli@48: 					+ " article retrieved - request text separately");
cli@37: 		}
cli@37: 	}
chris@1: }