LinkingQueueFileManager.java

/*
* Copyright 2013, CMM, University of Queensland.
*
* This file is part of Paul.
*
* Paul is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Paul is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Paul. If not, see <http://www.gnu.org/licenses/>.
*/

package au.edu.uq.cmm.paul.queue;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.attribute.FileAttribute;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import au.edu.uq.cmm.paul.PaulConfiguration;

/**
 * This queue file manager uses symbolic links where possible for files in the queue.
 * 
 * @author scrawley
 */
public class LinkingQueueFileManager extends AbstractQueueFileManager implements QueueFileManager {
    
    static final Logger LOG = LoggerFactory.getLogger(LinkingQueueFileManager.class);
    
    public LinkingQueueFileManager(PaulConfiguration config) {
        super(config, LOG);
    }

	/**
	 * {@inheritDoc}
	 * 
	 * This implementation enqueues a file by creating a symbolic link to it.
	 */
    @Override
    public File enqueueFile(File source, String suffix, boolean regrabbing) 
                throws QueueFileException, InterruptedException {
        File target = generateUniqueFile(suffix, regrabbing);
        try {
            Files.createSymbolicLink(target.toPath(), source.toPath(),
                    new FileAttribute<?>[0]);
            LOG.debug("Symlinked " + source + " as " + target);
            return target;
        } catch (IOException ex) {
            throw new QueueFileException("Problem while copying file to queue", ex);
        }
    }
}