org.apache.lucene.store

Class FSDirectory

java.lang.Object

org.apache.lucene.store.Directory

org.apache.lucene.store.FSDirectory

Direct Known Subclasses:

MMapDirectory, NIOFSDirectory

public class FSDirectory
extends Directory

Straightforward implementation of Directory as a directory of files. Locking implementation is by default the SimpleFSLockFactory, but can be changed either by passing in a LockFactory instance to getDirectory, or specifying the LockFactory class by setting org.apache.lucene.store.FSDirectoryLockFactoryClass Java system property, or by calling Directory.setLockFactory(org.apache.lucene.store.LockFactory) after creating the Directory.

Directories are cached, so that, for a given canonical path, the same FSDirectory instance will always be returned by getDirectory. This permits synchronization on directories.

See Also:

Directory

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	FSDirectory.FSIndexInput
protected static class	FSDirectory.FSIndexOutput

Field Summary

Fields

Modifier and Type

Field and Description

static String

LOCK_DIR Deprecated. As of 2.1, LOCK_DIR is unused because the write.lock is now stored by default in the index directory. If you really want to store locks elsewhere you can create your own SimpleFSLockFactory (or NativeFSLockFactory, etc.) passing in your preferred lock directory. Then, pass this LockFactory instance to one of the getDirectory methods that take a lockFactory (for example, getDirectory(String, LockFactory)).

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

lockFactory

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	FSDirectory()

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Closes the store to future operations.
IndexOutput	createOutput(String name) 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 in bytes of a file in the directory.
static long	fileModified(File directory, String name) Returns the time the named file was last modified.
long	fileModified(String name) Returns the time the named file was last modified.
static FSDirectory	getDirectory(File file) Returns the directory instance for the named location.
static FSDirectory	getDirectory(File file, boolean create) Deprecated. Use IndexWriter's create flag, instead, to create a new index.
static FSDirectory	getDirectory(File file, LockFactory lockFactory) Returns the directory instance for the named location.
static FSDirectory	getDirectory(String path) Returns the directory instance for the named location.
static FSDirectory	getDirectory(String path, boolean create) Deprecated. Use IndexWriter's create flag, instead, to create a new index.
static FSDirectory	getDirectory(String path, LockFactory lockFactory) Returns the directory instance for the named location.
static boolean	getDisableLocks() Returns whether Lucene's use of lock files is disabled.
File	getFile()
String	getLockID() Return a string identifier that uniquely differentiates this Directory instance from other Directory instances.
String[]	list() Returns an array of strings, one for each Lucene index file in the directory.
IndexInput	openInput(String name) Returns a stream reading an existing file.
IndexInput	openInput(String name, int bufferSize) Returns a stream reading an existing file, with the specified read buffer size.
void	renameFile(String from, String to) Deprecated.
static void	setDisableLocks(boolean doDisableLocks) Set whether Lucene's use of lock files is disabled.
void	sync(String name) Ensure that any writes to this file are moved to stable storage.
String	toString() For debug output.
void	touchFile(String name) Set the modified time of an existing file to now.

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

clearLock, copy, ensureOpen, getLockFactory, makeLock, setLockFactory

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

LOCK_DIR

public static final String LOCK_DIR

Deprecated. As of 2.1, LOCK_DIR is unused because the write.lock is now stored by default in the index directory. If you really want to store locks elsewhere you can create your own SimpleFSLockFactory (or NativeFSLockFactory, etc.) passing in your preferred lock directory. Then, pass this LockFactory instance to one of the getDirectory methods that take a lockFactory (for example, getDirectory(String, LockFactory)).

Directory specified by org.apache.lucene.lockDir or java.io.tmpdir system property.

Constructor Detail

FSDirectory

protected FSDirectory()

Method Detail

setDisableLocks

public static void setDisableLocks(boolean doDisableLocks)

Set whether Lucene's use of lock files is disabled. By default, lock files are enabled. They should only be disabled if the index is on a read-only medium like a CD-ROM.

getDisableLocks

public static boolean getDisableLocks()

Returns whether Lucene's use of lock files is disabled.

Returns:

true if locks are disabled, false if locks are enabled.

getDirectory

public static FSDirectory getDirectory(String path)
                                throws IOException

Returns the directory instance for the named location.

Parameters:

path - the path to the directory.

Returns:

the FSDirectory for the named file.

Throws:

IOException

getDirectory

public static FSDirectory getDirectory(String path,
                       LockFactory lockFactory)
                                throws IOException

Returns the directory instance for the named location.

Parameters:

path - the path to the directory.

lockFactory - instance of LockFactory providing the locking implementation.

Returns:

the FSDirectory for the named file.

Throws:

IOException

getDirectory

public static FSDirectory getDirectory(File file)
                                throws IOException

Returns the directory instance for the named location.

Parameters:

file - the path to the directory.

Returns:

the FSDirectory for the named file.

Throws:

IOException

getDirectory

public static FSDirectory getDirectory(File file,
                       LockFactory lockFactory)
                                throws IOException

Returns the directory instance for the named location.

Parameters:

file - the path to the directory.

lockFactory - instance of LockFactory providing the locking implementation.

Returns:

the FSDirectory for the named file.

Throws:

IOException

getDirectory

public static FSDirectory getDirectory(String path,
                       boolean create)
                                throws IOException

Deprecated. Use IndexWriter's create flag, instead, to create a new index.

Returns the directory instance for the named location.

Parameters:

path - the path to the directory.

create - if true, create, or erase any existing contents.

Returns:

the FSDirectory for the named file.

Throws:

IOException

getDirectory

public static FSDirectory getDirectory(File file,
                       boolean create)
                                throws IOException

Deprecated. Use IndexWriter's create flag, instead, to create a new index.

Returns the directory instance for the named location.

Parameters:

file - the path to the directory.

create - if true, create, or erase any existing contents.

Returns:

the FSDirectory for the named file.

Throws:

IOException

list

public String[] list()

Returns an array of strings, one for each Lucene index file in the directory.

Specified by:

list in class Directory

fileExists

public boolean fileExists(String name)

Returns true iff a file with the given name exists.

Specified by:

fileExists in class Directory

fileModified

public long fileModified(String name)

Returns the time the named file was last modified.

Specified by:

fileModified in class Directory

fileModified

public static long fileModified(File directory,
                String name)

Returns the time the named file was last modified.

touchFile

public void touchFile(String name)

Set the modified time of an existing file to now.

Specified by:

touchFile in class Directory

fileLength

public long fileLength(String name)

Returns the length in bytes of a file in the directory.

Specified by:

fileLength in class Directory

deleteFile

public void deleteFile(String name)
                throws IOException

Removes an existing file in the directory.

Specified by:

deleteFile in class Directory

Throws:

IOException

renameFile

public void renameFile(String from,
              String to)
                throws IOException

Deprecated.

Renames an existing file in the directory. Warning: This is not atomic.

Specified by:

renameFile in class Directory

Throws:

IOException

createOutput

public IndexOutput createOutput(String name)
                         throws IOException

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(String name)
          throws IOException

Description copied from class: Directory

Ensure that any writes to this file 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.

Overrides:

sync in class Directory

Throws:

IOException

openInput

public IndexInput openInput(String name)
                     throws IOException

Description copied from class: Directory

Returns a stream reading an existing file.

Specified by:

openInput in class Directory

Throws:

IOException

openInput

public IndexInput openInput(String name,
                   int bufferSize)
                     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 CompoundFileReader.

Overrides:

openInput in class Directory

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

close

public void close()

Closes the store to future operations.

Specified by:

close in class Directory

getFile

public File getFile()

toString

public String toString()

For debug output.

Overrides:

toString in class Object