# Uses of Class
org.apache.lucene.store.FilterDirectory

Packages that use FilterDirectory
Package
Description
org.apache.lucene.store
Binary i/o API, used for all index data.

- ## Uses of FilterDirectory in org.apache.lucene.store

  Subclasses of FilterDirectory in org.apache.lucene.store
  Modifier and Type
  Class
  Description
  `final class`
  `LockValidatingDirectoryWrapper`
  This class makes a best-effort check that a provided `Lock` is valid before any destructive filesystem operation.
  `class`
  `NRTCachingDirectory`
  Wraps a RAM-resident directory around any provided delegate directory, to be used during NRT search.
  `final class`
  `SleepingLockWrapper`
  Directory that wraps another, and that sleeps and retries if obtaining the lock fails.
  `final class`
  `TrackingDirectoryWrapper`
  A delegating Directory that records which files were written to and deleted.