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