Package org.apache.lucene.store

Class SimpleFSLockFactory

java.lang.Object

org.apache.lucene.store.LockFactory

org.apache.lucene.store.FSLockFactory

org.apache.lucene.store.SimpleFSLockFactory

public final class SimpleFSLockFactory
extends FSLockFactory

Implements LockFactory using Files.createFile(java.nio.file.Path, java.nio.file.attribute.FileAttribute<?>...).

The main downside with using this API for locking is that the Lucene write lock may not be released when the JVM exits abnormally.

When this happens, an LockObtainFailedException is hit when trying to create a writer, in which case you may need to explicitly clear the lock file first by manually removing the file. But, first be certain that no writer is in fact writing to the index otherwise you can easily corrupt your index.

Special care needs to be taken if you change the locking implementation: First be certain that no writer is in fact writing to the index otherwise you can easily corrupt your index. Be sure to do the LockFactory change all Lucene instances and clean up all leftover lock files before starting the new configuration for the first time. Different implementations can not work together!

If you suspect that this or any other LockFactory is not working properly in your environment, you can easily test it by using VerifyingLockFactory, LockVerifyServer and LockStressTest.

This is a singleton, you have to use INSTANCE.

See Also:

LockFactory

Field Summary

Fields

Modifier and Type	Field	Description
static SimpleFSLockFactory	INSTANCE	Singleton instance

Method Summary

Modifier and Type	Method	Description
protected Lock	obtainFSLock(FSDirectory dir, String lockName)	Implement this method to obtain a lock for a FSDirectory instance.

Methods inherited from class org.apache.lucene.store.FSLockFactory

getDefault, obtainLock

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

INSTANCE

public static final SimpleFSLockFactory INSTANCE

Singleton instance

Method Detail

obtainFSLock

protected Lock obtainFSLock(FSDirectory dir,
                            String lockName)
                     throws IOException

Description copied from class: FSLockFactory

Implement this method to obtain a lock for a FSDirectory instance.

Specified by:

obtainFSLock in class FSLockFactory

Throws:

IOException - if the lock could not be obtained.