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
021 import org.apache.camel.Exchange;
022 import org.apache.camel.component.file.FileComponent;
023 import org.apache.camel.component.file.GenericFile;
024 import org.apache.camel.component.file.GenericFileExclusiveReadLockStrategy;
025 import org.apache.camel.component.file.GenericFileOperations;
026 import org.apache.camel.util.ExchangeHelper;
027 import org.apache.commons.logging.Log;
028 import org.apache.commons.logging.LogFactory;
029
030 /**
031 * Acquires read lock to the given file using a marker file so other Camel consumers wont acquire the same file.
032 * This is the default behavior in Camel 1.x.
033 */
034 public class MarkerFileExclusiveReadLockStrategy implements GenericFileExclusiveReadLockStrategy<File> {
035 private static final transient Log LOG = LogFactory.getLog(MarkerFileExclusiveReadLockStrategy.class);
036
037 @SuppressWarnings("unchecked")
038 public boolean acquireExclusiveReadLock(GenericFileOperations<File> fileGenericFileOperations,
039 GenericFile<File> file, Exchange exchange) throws Exception {
040
041 String lockFileName = file.getAbsoluteFilePath() + FileComponent.DEFAULT_LOCK_FILE_POSTFIX;
042 if (LOG.isTraceEnabled()) {
043 LOG.trace("Locking the file: " + file + " using the lock file name: " + lockFileName);
044 }
045
046 // create a plain file as marker filer for locking (do not use FileLock)
047 File lock = new File(lockFileName);
048 boolean acquired = lock.createNewFile();
049 if (acquired) {
050 exchange.setProperty("CamelFileLock", lock);
051 exchange.setProperty("CamelFileLockName", lockFileName);
052 }
053
054 return acquired;
055 }
056
057 public void releaseExclusiveReadLock(GenericFileOperations<File> operations,
058 GenericFile<File> file, Exchange exchange) throws Exception {
059
060 File lock = ExchangeHelper.getMandatoryProperty(exchange, "CamelFileLock", File.class);
061 String lockFileName = ExchangeHelper.getMandatoryProperty(exchange, "CamelFileLockName", String.class);
062
063 if (LOG.isTraceEnabled()) {
064 LOG.trace("Unlocking file: " + lockFileName);
065 }
066
067 boolean deleted = lock.delete();
068 if (LOG.isTraceEnabled()) {
069 LOG.trace("Lock file: " + lockFileName + " was deleted: " + deleted);
070 }
071 }
072
073 public void setTimeout(long timeout) {
074 // noop
075 }
076
077 }