org.apache.lucene.store

Class FSDirectory

Known Direct Subclasses:
MMapDirectory

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 FSDirectory 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.

Author:
Doug Cutting
See Also:
Directory

Field Summary

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.

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

lockFactory

Constructor Summary

FSDirectory()

Method Summary

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.
void
renameFile(String from, String to)
Deprecated.
static void
setDisableLocks(boolean doDisableLocks)
Set whether Lucene's use of lock files is disabled.
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, close, copy, createOutput, deleteFile, fileExists, fileLength, fileModified, getLockFactory, getLockID, list, makeLock, openInput, renameFile, setLockFactory, touchFile

Field Details

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 Details

FSDirectory

protected FSDirectory()

Method Details

close

public void close()
Closes the store to future operations.
Overrides:
close in interface Directory

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.
Overrides:
createOutput in interface Directory

deleteFile

public void deleteFile(String name)
            throws IOException
Removes an existing file in the directory.
Overrides:
deleteFile in interface Directory

fileExists

public boolean fileExists(String name)
Returns true iff a file with the given name exists.
Overrides:
fileExists in interface Directory

fileLength

public long fileLength(String name)
Returns the length in bytes of a file in the directory.
Overrides:
fileLength in interface Directory

fileModified

public static long fileModified(File directory,
                                String name)
Returns the time the named file was last modified.

fileModified

public long fileModified(String name)
Returns the time the named file was last modified.
Overrides:
fileModified in interface Directory

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.

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.

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.

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.

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.

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.

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.

getFile

public File getFile()

getLockID

public String getLockID()
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 interface Directory

list

public String[] list()
Returns an array of strings, one for each Lucene index file in the directory.
Overrides:
list in interface Directory

openInput

public IndexInput openInput(String name)
            throws IOException
Returns a stream reading an existing file.
Overrides:
openInput in interface Directory

renameFile

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

Deprecated.

Renames an existing file in the directory. Warning: This is not atomic.
Overrides:
renameFile in interface Directory

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.

toString

public String toString()
For debug output.

touchFile

public void touchFile(String name)
Set the modified time of an existing file to now.
Overrides:
touchFile in interface Directory

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