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: 47012 $
036     */
037    public abstract class FileProcessStrategySupport implements FileProcessStrategy {
038        private static final transient Log LOG = LogFactory.getLog(FileProcessStrategySupport.class);
039        private boolean lockFile;
040        private FileRenamer lockFileRenamer;
041    
042        protected FileProcessStrategySupport() {
043            this(true);
044        }
045    
046        protected FileProcessStrategySupport(boolean lockFile) {
047            this(lockFile, new DefaultFileRenamer(null, FileEndpoint.DEFAULT_LOCK_FILE_POSTFIX));
048        }
049    
050        protected FileProcessStrategySupport(boolean lockFile, FileRenamer lockFileRenamer) {
051            this.lockFile = lockFile;
052            this.lockFileRenamer = lockFileRenamer;
053        }
054    
055        public boolean begin(FileEndpoint endpoint, FileExchange exchange, File file) throws Exception {
056            if (isLockFile()) {
057                File newFile = lockFileRenamer.renameFile(exchange, file);
058                String lockFileName = newFile.getAbsolutePath();
059                if (LOG.isDebugEnabled()) {
060                    LOG.debug("Locking the file: " + file + " using the lock file name: " + lockFileName);
061                }
062    
063                FileChannel channel = new RandomAccessFile(lockFileName, "rw").getChannel();
064                FileLock lock = channel.lock();
065                if (lock != null) {
066                    exchange.setProperty("org.apache.camel.fileChannel", channel);
067                    exchange.setProperty("org.apache.camel.file.lock", lock);
068                    exchange.setProperty("org.apache.camel.file.lock.name", lockFileName);
069                    return true;
070                }
071                return false;
072            }
073            return true;
074        }
075    
076        public void commit(FileEndpoint endpoint, FileExchange exchange, File file) throws Exception {
077            unlockFile(endpoint, exchange, file);
078        }
079    
080        public void rollback(FileEndpoint endpoint, FileExchange exchange, File file) {
081            try {
082                unlockFile(endpoint, exchange, file);
083            } catch (Exception e) {
084                LOG.info("Unable to unlock file: " + file + ": " + e.getMessage(), e);
085            }
086        }
087    
088        public boolean isLockFile() {
089            return lockFile;
090        }
091    
092        public void setLockFile(boolean lockFile) {
093            this.lockFile = lockFile;
094        }
095    
096        public FileRenamer getLockFileRenamer() {
097            return lockFileRenamer;
098        }
099    
100        public void setLockFileRenamer(FileRenamer lockFileRenamer) {
101            this.lockFileRenamer = lockFileRenamer;
102        }
103    
104        protected void unlockFile(FileEndpoint endpoint, FileExchange exchange, File file) throws Exception {
105            if (isLockFile()) {
106                Channel channel = ExchangeHelper.getMandatoryProperty(exchange, "org.apache.camel.fileChannel", Channel.class);
107                String lockfile = ExchangeHelper.getMandatoryProperty(exchange, "org.apache.camel.file.lock.name", String.class);
108                if (LOG.isDebugEnabled()) {
109                    LOG.debug("Unlocking file: " + file);
110                }
111                channel.close();
112                File lock = new File(lockfile);
113                lock.delete();
114            }
115        }
116    }