Implements {@link LockFactory} using native OS filelocks. Note that because this LockFactory relies on java.nio.* APIs for locking, any problems with those APIs will cause locking to fail. Specifically, on certain NFS environments the java.nio.* locks will fail (the lock can incorrectly be double acquired) whereas {@link SimpleFSLockFactory} worked perfectly in those sameenvironments. For NFS based access to an index, it's recommended that you try {@link SimpleFSLockFactory}first and work around the one limitation that a lock file could be left when the JVM exits abnormally.
The primary benefit of {@link NativeFSLockFactory} isthat lock files will be properly removed (by the OS) if the JVM has an abnormal exit.
Note that, unlike {@link SimpleFSLockFactory}, the existence of leftover lock files in the filesystem on exiting the JVM is fine because the OS will free the locks held against these files even though the files still remain.
If you suspect that this or any other LockFactory is not working properly in your environment, you can easily test it by using {@link VerifyingLockFactory}, {@link LockVerifyServer} and {@link LockStressTest}.
@see LockFactory | |