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 class SimpleFSLockFactory extends FSLockFactory

Implements LockFactory using File.createNewFile().

NOTE: the javadocs for File.createNewFile() contain a vague yet spooky warning about not using the API for file locking. This warning was added due to this bug, and in fact the only known problem with using this API for locking is that the Lucene write lock may not be released when the JVM exits abnormally.

When this happens, a LockObtainFailedException is hit when trying to create a writer, in which case you need to explicitly clear the lock file first. You can either manually remove the file, or use the IndexWriter.unlock(Directory) API. But, first be certain that no writer is in fact writing to the index otherwise you can easily corrupt your index.

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.

See Also:

  • Constructor Details

    • SimpleFSLockFactory

      public SimpleFSLockFactory()
      Create a SimpleFSLockFactory instance, with null (unset) lock directory. When you pass this factory to a FSDirectory subclass, the lock directory is automatically set to the directory itself. Be sure to create one instance for each directory your create!

    • SimpleFSLockFactory

      public SimpleFSLockFactory(File lockDir)
      Instantiate using the provided directory (as a File instance).
      Parameters:
      lockDir - where lock files should be created.

    • SimpleFSLockFactory

      public SimpleFSLockFactory(String lockDirName)
      Instantiate using the provided directory name (String).
      Parameters:
      lockDirName - where lock files should be created.

  • Method Details

    • makeLock

      public Lock makeLock(String lockName)
      Description copied from class: LockFactory
      Return a new Lock instance identified by lockName.
      Specified by:
      makeLock in class LockFactory
      Parameters:
      lockName - name of the lock to be created.

    • clearLock

      public void clearLock(String lockName) throws IOException
      Description copied from class: LockFactory
      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.
      Specified by:
      clearLock in class LockFactory
      Parameters:
      lockName - name of the lock to be cleared.
      Throws:
      IOException