org.apache.lucene.store
Class FilterDirectory

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

All Implemented Interfaces:

Closeable

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.

NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

Nested Class Summary

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

Directory.IndexInputSlicer

Field Summary

protected Directory

in

Constructor Summary

protected

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

Method Summary

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 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