java.lang.Object
- org.apache.lucene.store.Directory
- - org.apache.lucene.store.FilterDirectory

All Implemented Interfaces:

Closeable, AutoCloseable

Direct Known Subclasses:

RateLimitedDirectoryWrapper, TrackingDirectoryWrapper
```
public class FilterDirectory
extends Directory
```
Directory implementation that delegates calls to another directory. This class can be used to add limitations on top of an existing Directory implementation such as rate limiting or to add additional sanity checks for tests. However, if you plan to write your own Directory implementation, you should consider extending directly Directory or BaseDirectory rather than try to reuse functionality of existing Directorys by extending this class.

Nested Class Summary
- Nested classes/interfaces inherited from class org.apache.lucene.store.Directory
  Directory.IndexInputSlicer

Field Summary

Fields
Modifier and Type Field Description

protected Directory in

Constructor Summary

Constructors
Modifier Constructor Description

protected FilterDirectory(Directory in)
Sole constructor, typically called from sub-classes.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`clearLock(String name)`	Attempt to clear (forcefully unlock and remove) the specified lock.
`void`	`close()`	Closes the store.
`IndexOutput`	`createOutput(String name, IOContext context)`	Creates a new, empty file in the directory with the given name.
`void`	`deleteFile(String name)`	Removes an existing file in the directory.
`boolean`	`fileExists(String name)`	Returns true iff a file with the given name exists.
`long`	`fileLength(String name)`	Returns the length of a file in the directory.
`Directory`	`getDelegate()`	Return the wrapped `Directory`.
`LockFactory`	`getLockFactory()`	Get the LockFactory that this Directory instance is using for its locking implementation.
`String`	`getLockID()`	Return a string identifier that uniquely differentiates this Directory instance from other Directory instances.
`String[]`	`listAll()`	Returns an array of strings, one for each file in the directory.
`Lock`	`makeLock(String name)`	Construct a `Lock`.
`IndexInput`	`openInput(String name, IOContext context)`	Returns a stream reading an existing file, with the specified read buffer size.
`void`	`setLockFactory(LockFactory lockFactory)`	Set the LockFactory that this Directory instance should use for its locking implementation.
`void`	`sync(Collection<String> names)`	Ensure that any writes to these files are moved to stable storage.
`String`	`toString()`

Methods inherited from class org.apache.lucene.store.Directory
copy, createSlicer, ensureOpen

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - in
```
protected final Directory in
```
- Constructor Detail
  - FilterDirectory
```
protected FilterDirectory(Directory in)
```
    Sole constructor, typically called from sub-classes.
- Method Detail
  - getDelegate
```
public final Directory getDelegate()
```
    Return the wrapped Directory.
  - listAll
```
public String[] listAll()
                 throws IOException
```
    Description copied from class: Directory
    
    Returns an array of strings, one for each file in the directory.
    
    Specified by:
    
    listAll in class Directory
    
    Throws:
    
    NoSuchDirectoryException - if the directory is not prepared for any write operations (such as Directory.createOutput(String, IOContext)).
    
    IOException - in case of other IO errors
  - fileExists
```
public boolean fileExists(String name)
                   throws IOException
```
    Description copied from class: Directory
    
    Returns true iff a file with the given name exists.
    
    Specified by:
    
    fileExists in class Directory
    
    Throws:
    
    IOException
  - deleteFile
```
public void deleteFile(String name)
                throws IOException
```
    Description copied from class: Directory
    
    Removes an existing file in the directory.
    
    Specified by:
    
    deleteFile in class Directory
    
    Throws:
    
    IOException
  - fileLength
```
public long fileLength(String name)
                throws IOException
```
    Description copied from class: Directory
    Returns the length of a file in the directory. This method follows the following contract:
    
    Must throw FileNotFoundException if the file does not exist (not java.nio.file.NoSuchFileException of Java 7).
    Returns a value ≥0 if the file exists, which specifies its length.
    Specified by:
    
    fileLength in class Directory
    
    Parameters:
    
    name - the name of the file for which to return the length.
    
    Throws:
    
    IOException - if there was an IO error while retrieving the file's length.
  - createOutput
```
public IndexOutput createOutput(String name,
                                IOContext context)
                         throws IOException
```
    Description copied from class: Directory
    
    Creates a new, empty file in the directory with the given name. Returns a stream writing this file.
    
    Specified by:
    
    createOutput in class Directory
    
    Throws:
    
    IOException
  - sync
```
public void sync(Collection<String> names)
          throws IOException
```
    Description copied from class: Directory
    
    Ensure that any writes to these files are moved to stable storage. Lucene uses this to properly commit changes to the index, to prevent a machine/OS crash from corrupting the index.
    
    NOTE: Clients may call this method for same files over and over again, so some impls might optimize for that. For other impls the operation can be a noop, for various reasons.
    
    Specified by:
    
    sync in class Directory
    
    Throws:
    
    IOException
  - openInput
```
public IndexInput openInput(String name,
                            IOContext context)
                     throws IOException
```
    Description copied from class: Directory
    
    Returns a stream reading an existing file, with the specified read buffer size. The particular Directory implementation may ignore the buffer size. Currently the only Directory implementations that respect this parameter are FSDirectory and CompoundFileDirectory.
  - Must throw FileNotFoundException if the file does not exist (not java.nio.file.NoSuchFileException of Java 7).

Specified by:: openInput in class Directory
Throws:: IOException

makeLock
```
public Lock makeLock(String name)
```
Description copied from class: Directory

Construct a Lock.

Specified by:

makeLock in class Directory

Parameters:

name - the name of the lock file

clearLock
```
public void clearLock(String name)
               throws IOException
```
Description copied from class: Directory

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 Directory

Parameters:

name - name of the lock to be cleared.

Throws:

IOException

close
```
public void close()
           throws IOException
```
Description copied from class: Directory

Closes the store.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in class Directory

Throws:

IOException

setLockFactory
```
public void setLockFactory(LockFactory lockFactory)
                    throws IOException
```
Description copied from class: Directory

Set the LockFactory that this Directory instance should use for its locking implementation. Each * instance of LockFactory should only be used for one directory (ie, do not share a single instance across multiple Directories).

Specified by:

setLockFactory in class Directory

Parameters:

lockFactory - instance of LockFactory.

Throws:

IOException

getLockID
```
public String getLockID()
```
Description copied from class: Directory

Return a string identifier that uniquely differentiates this Directory instance from other Directory instances. This ID should be the same if two Directory instances (even in different JVMs and/or on different machines) are considered "the same index". This is how locking "scopes" to the right index.

Overrides:

getLockID in class Directory

getLockFactory
```
public LockFactory getLockFactory()
```
Description copied from class: Directory

Get the LockFactory that this Directory instance is using for its locking implementation. Note that this may be null for Directory implementations that provide their own locking implementation.

Specified by:

getLockFactory in class Directory

toString
```
public String toString()
```
Overrides:

toString in class Directory

Class FilterDirectory

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.store.Directory

Field Summary

Constructor Summary

Method Summary

Methods inherited from class org.apache.lucene.store.Directory

Methods inherited from class java.lang.Object

Field Detail

in

Constructor Detail

FilterDirectory

Method Detail

getDelegate

listAll

fileExists

deleteFile

fileLength

createOutput

sync

openInput

makeLock

clearLock

close

setLockFactory

getLockID

getLockFactory

toString