Package org.apache.lucene.store

Class LockFactory

java.lang.Object

org.apache.lucene.store.LockFactory

Direct Known Subclasses:

FSLockFactory, NoLockFactory, SingleInstanceLockFactory, VerifyingLockFactory

public abstract class LockFactory
extends Object

Base class for Locking implementation. Directory uses instances of this class to implement locking.

Lucene uses NativeFSLockFactory by default for FSDirectory-based index directories.

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 on 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 some LockFactory implementation is not working properly in your environment, you can easily test it by using VerifyingLockFactory, LockVerifyServer and LockStressTest.

See Also:

• LockVerifyServer
• LockStressTest
• VerifyingLockFactory

Constructor Summary

Constructors

Constructor	Description
LockFactory()

Method Summary

Modifier and Type	Method	Description
abstract Lock	obtainLock(Directory dir, String lockName)	Return a new obtained Lock instance identified by lockName.

Methods inherited from class java.lang.Object

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

Constructor Details

LockFactory

public LockFactory()

Method Details

obtainLock

public abstract Lock obtainLock(Directory dir,
 String lockName)
                         throws IOException

Return a new obtained Lock instance identified by lockName.

Parameters:

lockName - name of the lock to be created.

Throws:

LockObtainFailedException - (optional specific exception) if the lock could not be obtained because it is currently held elsewhere.

IOException - if any i/o error occurs attempting to gain the lock