@Override
public void releaseExclusiveReadLock(
GenericFileOperations<File> operations, GenericFile<File> file, Exchange exchange)
throws Exception {
// must call super
super.releaseExclusiveReadLock(operations, file, exchange);
String target = file.getFileName();
FileLock lock = exchange.getProperty(Exchange.FILE_LOCK_EXCLUSIVE_LOCK, FileLock.class);
RandomAccessFile rac =
exchange.getProperty(Exchange.FILE_LOCK_RANDOM_ACCESS_FILE, RandomAccessFile.class);
if (lock != null) {
Channel channel = lock.acquiredBy();
try {
lock.release();
} finally {
// close channel as well
IOHelper.close(channel, "while releasing exclusive read lock for file: " + target, LOG);
IOHelper.close(rac, "while releasing exclusive read lock for file: " + target, LOG);
}
}
}
@Override
public boolean acquireExclusiveReadLock(
GenericFileOperations<File> operations, GenericFile<File> file, Exchange exchange)
throws Exception {
// must call super
if (!super.acquireExclusiveReadLock(operations, file, exchange)) {
return false;
}
File target = new File(file.getAbsoluteFilePath());
LOG.trace("Waiting for exclusive read lock to file: {}", target);
FileChannel channel = null;
RandomAccessFile randomAccessFile = null;
boolean exclusive = false;
FileLock lock = null;
try {
randomAccessFile = new RandomAccessFile(target, "rw");
// try to acquire rw lock on the file before we can consume it
channel = randomAccessFile.getChannel();
StopWatch watch = new StopWatch();
while (!exclusive) {
// timeout check
if (timeout > 0) {
long delta = watch.taken();
if (delta > timeout) {
CamelLogger.log(
LOG,
readLockLoggingLevel,
"Cannot acquire read lock within "
+ timeout
+ " millis. Will skip the file: "
+ target);
// we could not get the lock within the timeout period, so return false
return false;
}
}
// get the lock using either try lock or not depending on if we are using timeout or not
try {
lock = timeout > 0 ? channel.tryLock() : channel.lock();
} catch (IllegalStateException ex) {
// Also catch the OverlappingFileLockException here. Do nothing here
}
if (lock != null) {
LOG.trace("Acquired exclusive read lock: {} to file: {}", lock, target);
exclusive = true;
} else {
boolean interrupted = sleep();
if (interrupted) {
// we were interrupted while sleeping, we are likely being shutdown so return false
return false;
}
}
}
} catch (IOException e) {
// must handle IOException as some apps on Windows etc. will still somehow hold a lock to a
// file
// such as AntiVirus or MS Office that has special locks for it's supported files
if (timeout == 0) {
// if not using timeout, then we cant retry, so return false
return false;
}
LOG.debug("Cannot acquire read lock. Will try again.", e);
boolean interrupted = sleep();
if (interrupted) {
// we were interrupted while sleeping, we are likely being shutdown so return false
return false;
}
} finally {
// close channels if we did not grab the lock
if (!exclusive) {
IOHelper.close(channel, "while acquiring exclusive read lock for file: " + target, LOG);
IOHelper.close(
randomAccessFile, "while acquiring exclusive read lock for file: " + target, LOG);
// and also must release super lock
super.releaseExclusiveReadLock(operations, file, exchange);
}
}
// we grabbed the lock
exchange.setProperty(Exchange.FILE_LOCK_EXCLUSIVE_LOCK, lock);
exchange.setProperty(Exchange.FILE_LOCK_RANDOM_ACCESS_FILE, randomAccessFile);
return true;
}
