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

Field Summary

Fields

Modifier and Type	Field and Description
protected String	lockPrefix

Constructor Summary

Constructors

Constructor and Description
LockFactory()

Method Summary

Methods

Modifier and Type	Method and Description
abstract void	clearLock(String lockName) Attempt to clear (forcefully unlock and remove) the specified lock.
String	getLockPrefix() Get the prefix in use for all locks created in this LockFactory.
abstract Lock	makeLock(String lockName) Return a new Lock instance identified by lockName.
void	setLockPrefix(String lockPrefix) Set the prefix in use for all locks created in this LockFactory.

Methods inherited from class java.lang.Object

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

Field Detail

lockPrefix

protected String lockPrefix

Constructor Detail

LockFactory

public LockFactory()

Method Detail

setLockPrefix

public void setLockPrefix(String lockPrefix)

Set the prefix in use for all locks created in this LockFactory. This is normally called once, when a Directory gets this LockFactory instance. However, you can also call this (after this instance is assigned to a Directory) to override the prefix in use. This is helpful if you're running Lucene on machines that have different mount points for the same shared directory.

getLockPrefix

public String getLockPrefix()

Get the prefix in use for all locks created in this LockFactory.

makeLock

public abstract Lock makeLock(String lockName)

Return a new Lock instance identified by lockName.

Parameters:

lockName - name of the lock to be created.

clearLock

public abstract void clearLock(String lockName)
                        throws IOException

Attempt to clear (forcefully unlock and remove) the specified lock. Only call this at a time when you are certain this lock is no longer in use.

Parameters:

lockName - name of the lock to be cleared.

Throws:

IOException