gate.creole.annic.apache.lucene.store
Class FSDirectory

java.lang.Object
  gate.creole.annic.apache.lucene.store.Directory
      gate.creole.annic.apache.lucene.store.FSDirectory

public final class FSDirectory
extends Directory

Straightforward implementation of Directory as a directory of files.

If the system property 'disableLuceneLocks' has the String value of "true", lock creation will be disabled.

Author:

Doug Cutting

See Also:

Directory

Field Summary

private byte[]	buffer A buffer optionally used in renameTo method
private static MessageDigest	DIGESTER
private static Hashtable	DIRECTORIES This cache of directories ensures that there is a unique Directory instance per path, so that synchronization on the Directory can be used to synchronize access between readers and writers.
private File	directory
private static boolean	DISABLE_LOCKS
private static char[]	HEX_DIGITS So we can do some byte-to-hexchar conversion below
static String	LOCK_DIR Directory specified by gate.creole.annic.apache.lucene.lockdir or java.io.tmpdir system property
private File	lockDir
private int	refCount

Constructor Summary

private

FSDirectory(File path, boolean create)

Method Summary

void	close() Closes the store to future operations.
private void	create()
OutputStream	createFile(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, boolean create) Returns the directory instance for the named location.
static FSDirectory	getDirectory(String path, boolean create) Returns the directory instance for the named location.
File	getFile()
private StringBuffer	getLockPrefix()
String[]	list() Returns an array of strings, one for each file in the directory.
Lock	makeLock(String name) Constructs a Lock with the specified name.
InputStream	openFile(String name) Returns a stream reading an existing file.
void	renameFile(String from, String to) Renames an existing file in the directory.
String	toString() For debug output.
void	touchFile(String name) Set the modified time of an existing file to now.

Methods inherited from class java.lang.Object

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

Field Detail

DIRECTORIES

private static final Hashtable DIRECTORIES

This cache of directories ensures that there is a unique Directory instance per path, so that synchronization on the Directory can be used to synchronize access between readers and writers. This should be a WeakHashMap, so that entries can be GC'd, but that would require Java 1.2. Instead we use refcounts...

DISABLE_LOCKS

private static final boolean DISABLE_LOCKS

LOCK_DIR

public static final String LOCK_DIR

Directory specified by gate.creole.annic.apache.lucene.lockdir or java.io.tmpdir system property

DIGESTER

private static MessageDigest DIGESTER

buffer

private byte[] buffer

A buffer optionally used in renameTo method

directory

private File directory

refCount

private int refCount

lockDir

private File lockDir

HEX_DIGITS

private static final char[] HEX_DIGITS

So we can do some byte-to-hexchar conversion below

Constructor Detail

FSDirectory

private FSDirectory(File path,
                    boolean create)
             throws IOException

Throws:

IOException

Method Detail

getDirectory

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

Returns the directory instance for the named location.

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

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

Returns the directory instance for the named location.

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

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

create

private void create()
             throws IOException

Throws:

IOException

list

public final String[] list()
                    throws IOException

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

Specified by:

list in class Directory

Throws:

IOException

fileExists

public final boolean fileExists(String name)
                         throws IOException

Returns true iff a file with the given name exists.

Specified by:

fileExists in class Directory

Throws:

IOException

fileModified

public final long fileModified(String name)
                        throws IOException

Returns the time the named file was last modified.

Specified by:

fileModified in class Directory

Throws:

IOException

fileModified

public static final long fileModified(File directory,
                                      String name)
                               throws IOException

Returns the time the named file was last modified.

Throws:

IOException

touchFile

public void touchFile(String name)
               throws IOException

Set the modified time of an existing file to now.

Specified by:

touchFile in class Directory

Throws:

IOException

fileLength

public final long fileLength(String name)
                      throws IOException

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

Specified by:

fileLength in class Directory

Throws:

IOException

deleteFile

public final void deleteFile(String name)
                      throws IOException

Removes an existing file in the directory.

Specified by:

deleteFile in class Directory

Throws:

IOException

renameFile

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

Renames an existing file in the directory.

Specified by:

renameFile in class Directory

Throws:

IOException

createFile

public final OutputStream createFile(String name)
                              throws IOException

Creates a new, empty file in the directory with the given name. Returns a stream writing this file.

Specified by:

createFile in class Directory

Throws:

IOException

openFile

public final InputStream openFile(String name)
                           throws IOException

Returns a stream reading an existing file.

Specified by:

openFile in class Directory

Throws:

IOException

makeLock

public final Lock makeLock(String name)

Constructs a Lock with the specified name. Locks are implemented with File.createNewFile().

In JDK 1.1 or if system property disableLuceneLocks is the string "true", locks are disabled. Assigning this property any other string will not prevent creation of lock files. This is useful for using Lucene on read-only medium, such as CD-ROM.

Specified by:

makeLock in class Directory

Parameters:

name - the name of the lock file

Returns:

an instance of Lock holding the lock

getLockPrefix

private StringBuffer getLockPrefix()

close

public final void close()
                 throws IOException

Closes the store to future operations.

Specified by:

close in class Directory

Throws:

IOException

getFile

public File getFile()

toString

public String toString()

For debug output.

Overrides:

toString in class Object