001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.camel.component.file.strategy;
018    
019    import java.io.File;
020    import java.io.RandomAccessFile;
021    import java.nio.channels.Channel;
022    import java.nio.channels.FileChannel;
023    import java.nio.channels.FileLock;
024    
025    import org.apache.camel.component.file.FileEndpoint;
026    import org.apache.camel.component.file.FileExchange;
027    import org.apache.camel.component.file.FileProcessStrategy;
028    import org.apache.camel.util.ExchangeHelper;
029    import org.apache.commons.logging.Log;
030    import org.apache.commons.logging.LogFactory;
031    
032    /**
033     * Base class for {@link org.apache.camel.component.file.FileProcessStrategy} implementation to extend.
034     *
035     * @version $Revision: 37863 $
036     */
037    public abstract class FileProcessStrategySupport implements FileProcessStrategy {
038        public static final String DEFAULT_LOCK_FILE_POSTFIX = ".cameLock";
039        
040        private static final transient Log LOG = LogFactory.getLog(FileProcessStrategySupport.class);
041        private boolean lockFile;
042        private FileRenamer lockFileRenamer;
043    
044        protected FileProcessStrategySupport() {
045            this(true);
046        }
047    
048        protected FileProcessStrategySupport(boolean lockFile) {
049            this(lockFile, new DefaultFileRenamer(null, DEFAULT_LOCK_FILE_POSTFIX));
050        }
051    
052        protected FileProcessStrategySupport(boolean lockFile, FileRenamer lockFileRenamer) {
053            this.lockFile = lockFile;
054            this.lockFileRenamer = lockFileRenamer;
055        }
056    
057        public boolean begin(FileEndpoint endpoint, FileExchange exchange, File file) throws Exception {
058            if (isLockFile()) {
059                File newFile = lockFileRenamer.renameFile(file);
060                String lockFileName = newFile.getAbsolutePath();
061                if (LOG.isDebugEnabled()) {
062                    LOG.debug("Locking the file: " + file + " using the lock file name: " + lockFileName);
063                }
064    
065                FileChannel channel = new RandomAccessFile(lockFileName, "rw").getChannel();
066                FileLock lock = channel.lock();
067                if (lock != null) {
068                    exchange.setProperty("org.apache.camel.fileChannel", channel);
069                    exchange.setProperty("org.apache.camel.file.lock", lock);
070                    exchange.setProperty("org.apache.camel.file.lock.name", lockFileName);
071                    return true;
072                }
073                return false;
074            }
075            return true;
076        }
077    
078        public void commit(FileEndpoint endpoint, FileExchange exchange, File file) throws Exception {
079            if (isLockFile()) {
080                Channel channel = ExchangeHelper.getMandatoryProperty(exchange, "org.apache.camel.fileChannel", Channel.class);
081                String lockfile = ExchangeHelper.getMandatoryProperty(exchange, "org.apache.camel.file.lock.name", String.class);
082                if (LOG.isDebugEnabled()) {
083                    LOG.debug("Unlocking file: " + file);
084                }
085                channel.close();
086                File lock = new File(lockfile);
087                lock.delete();
088            }
089        }
090    
091        public boolean isLockFile() {
092            return lockFile;
093        }
094    
095        public void setLockFile(boolean lockFile) {
096            this.lockFile = lockFile;
097        }
098    
099        public FileRenamer getLockFileRenamer() {
100            return lockFileRenamer;
101        }
102    
103        public void setLockFileRenamer(FileRenamer lockFileRenamer) {
104            this.lockFileRenamer = lockFileRenamer;
105        }
106    }