src/org/sonews/daemon/command/NextPrevCommand.java
author František Kučera <franta-hg@frantovo.cz>
Wed Dec 31 12:07:40 2014 +0100 (2014-12-31)
changeset 120 bb1c8a7b774c
parent 37 74139325d305
permissions -rwxr-xr-x
XSLT: licence – GNU GPLv3
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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.Group;
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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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	@Override
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	public String[] getSupportedCommandStrings() {
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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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		return true;
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	}
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	@Override
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	public String impliedCapability() {
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		return null;
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	}
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	@Override
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	public boolean isStateful() {
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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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		final Article currA = conn.getCurrentArticle();
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		final Group currG = conn.getCurrentChannel();
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		if (currA == null) {
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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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			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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			selectNewArticle(conn, currA, currG, 1);
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		} else if (command[0].equalsIgnoreCase("PREV")) {
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			selectNewArticle(conn, currA, currG, -1);
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		} else {
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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, Group grp,
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			final int delta)
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			throws IOException, StorageBackendException {
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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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			conn.println("421 no next article in this group");
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		} else {
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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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}