# 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.