/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.camel.component.file.remote.strategy;
import java.util.List;
import org.apache.camel.Exchange;
import org.apache.camel.component.file.GenericFile;
import org.apache.camel.component.file.GenericFileEndpoint;
import org.apache.camel.component.file.GenericFileExclusiveReadLockStrategy;
import org.apache.camel.component.file.GenericFileOperations;
import org.apache.camel.util.StopWatch;
import org.apache.commons.net.ftp.FTPFile;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class FtpChangedExclusiveReadLockStrategy implements GenericFileExclusiveReadLockStrategy<FTPFile> {
private static final transient Logger LOG = LoggerFactory.getLogger(FtpChangedExclusiveReadLockStrategy.class);
private long timeout;
private long checkInterval = 5000;
private long minLength = 1;
private boolean fastExistsCheck;
@Override
public void prepareOnStartup(GenericFileOperations<FTPFile> tGenericFileOperations, GenericFileEndpoint<FTPFile> tGenericFileEndpoint) throws Exception {
// noop
}
public boolean acquireExclusiveReadLock(GenericFileOperations<FTPFile> operations, GenericFile<FTPFile> file, Exchange exchange) throws Exception {
boolean exclusive = false;
LOG.trace("Waiting for exclusive read lock to file: " + file);
long lastModified = Long.MIN_VALUE;
long length = Long.MIN_VALUE;
StopWatch watch = new StopWatch();
while (!exclusive) {
// timeout check
if (timeout > 0) {
long delta = watch.taken();
if (delta > timeout) {
LOG.warn("Cannot acquire read lock within " + timeout + " millis. Will skip the file: " + file);
// we could not get the lock within the timeout period, so return false
return false;
}
}
long newLastModified = 0;
long newLength = 0;
List<FTPFile> files;
if (fastExistsCheck) {
// use the absolute file path to only pickup the file we want to check, this avoids expensive
// list operations if we have a lot of files in the directory
LOG.trace("Using fast exists to update file information for {}", file);
files = operations.listFiles(file.getAbsoluteFilePath());
} else {
LOG.trace("Using full directory listing to update file information for {}. Consider enabling fastExistsCheck option.", file);
// fast option not enabled, so list the directory and filter the file name
files = operations.listFiles(file.getParent());
}
LOG.trace("List files {} found {} files", file.getAbsoluteFilePath(), files.size());
for (FTPFile f : files) {
if (f.getName().equals(file.getFileName())) {
newLastModified = f.getTimestamp().getTimeInMillis();
newLength = f.getSize();
}
}
LOG.trace("Previous last modified: " + lastModified + ", new last modified: " + newLastModified);
LOG.trace("Previous length: " + length + ", new length: " + newLength);
if (length >= minLength && (newLastModified == lastModified && newLength == length)) {
LOG.trace("Read lock acquired.");
exclusive = true;
} else {
// set new base file change information
lastModified = newLastModified;
length = newLength;
boolean interrupted = sleep();
if (interrupted) {
// we were interrupted while sleeping, we are likely being shutdown so return false
return false;
}
}
}
return exclusive;
}
private boolean sleep() {
LOG.trace("Exclusive read lock not granted. Sleeping for " + checkInterval + " millis.");
try {
Thread.sleep(checkInterval);
return false;
} catch (InterruptedException e) {
LOG.debug("Sleep interrupted while waiting for exclusive read lock, so breaking out");
return true;
}
}
@Override
public void releaseExclusiveReadLock(GenericFileOperations<FTPFile> tGenericFileOperations, GenericFile<FTPFile> tGenericFile, Exchange exchange) throws Exception {
// noop
}
public long getTimeout() {
return timeout;
}
public void setTimeout(long timeout) {
this.timeout = timeout;
}
public long getCheckInterval() {
return checkInterval;
}
public void setCheckInterval(long checkInterval) {
this.checkInterval = checkInterval;
}
public long getMinLength() {
return minLength;
}
public void setMinLength(long minLength) {
this.minLength = minLength;
}
public boolean isFastExistsCheck() {
return fastExistsCheck;
}
public void setFastExistsCheck(boolean fastExistsCheck) {
this.fastExistsCheck = fastExistsCheck;
}
}