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.Exchange;
026 import org.apache.camel.component.file.FileComponent;
027 import org.apache.camel.component.file.GenericFile;
028 import org.apache.camel.component.file.GenericFileExclusiveReadLockStrategy;
029 import org.apache.camel.component.file.GenericFileOperations;
030 import org.apache.camel.util.ExchangeHelper;
031 import org.apache.camel.util.ObjectHelper;
032 import org.apache.commons.logging.Log;
033 import org.apache.commons.logging.LogFactory;
034
035 /**
036 * Acquires read lock to the given file using a marker file so other Camel consumers wont acquire the same file.
037 * This is the default behaviour in Camel 1.x.
038 */
039 public class MarkerFileExclusiveReadLockStrategy implements GenericFileExclusiveReadLockStrategy<File> {
040 private static final transient Log LOG = LogFactory.getLog(MarkerFileExclusiveReadLockStrategy.class);
041
042 @SuppressWarnings("unchecked")
043 public boolean acquireExclusiveReadLock(GenericFileOperations<File> fileGenericFileOperations,
044 GenericFile<File> file, Exchange exchange) throws Exception {
045
046 String lockFileName = file.getAbsoluteFilePath() + FileComponent.DEFAULT_LOCK_FILE_POSTFIX;
047 if (LOG.isTraceEnabled()) {
048 LOG.trace("Locking the file: " + file + " using the lock file name: " + lockFileName);
049 }
050
051 FileChannel channel = new RandomAccessFile(lockFileName, "rw").getChannel();
052 FileLock lock = channel.lock();
053 if (lock != null) {
054 exchange.setProperty("CamelFileLock", lock);
055 exchange.setProperty("CamelFileLockName", lockFileName);
056 return true;
057 } else {
058 return false;
059 }
060 }
061
062 public void releaseExclusiveReadLock(GenericFileOperations<File> fileGenericFileOperations,
063 GenericFile<File> fileGenericFile, Exchange exchange) throws Exception {
064 FileLock lock = ExchangeHelper.getMandatoryProperty(exchange, "CamelFileLock", FileLock.class);
065 String lockFileName = ExchangeHelper.getMandatoryProperty(exchange, "CamelFileLockName", String.class);
066 Channel channel = lock.channel();
067
068 if (LOG.isTraceEnabled()) {
069 LOG.trace("Unlocking file: " + lockFileName);
070 }
071 try {
072 lock.release();
073 } finally {
074 // must close channel
075 ObjectHelper.close(channel, "Closing channel", LOG);
076
077 File lockfile = new File(lockFileName);
078 boolean deleted = lockfile.delete();
079 if (LOG.isTraceEnabled()) {
080 LOG.trace("Lock file: " + lockFileName + " was deleted: " + deleted);
081 }
082 }
083 }
084
085 public void setTimeout(long timeout) {
086 // noop
087 }
088
089 }