gate.creole.annic.apache.lucene.store

Class Directory

java.lang.Object

gate.creole.annic.apache.lucene.store.Directory

Direct Known Subclasses:

FSDirectory, RAMDirectory

public abstract class Directory
extends Object

A Directory is a flat list of files. Files may be written once, when they are created. Once a file is created it may only be opened for read, or deleted. Random access is permitted both when reading and writing.

Java's i/o APIs not used directly, but rather all i/o is through this API. This permits things such as:

• implementation of RAM-based indices;
• implementation of an index as a single file;

Author:

Doug Cutting

Constructor Summary

Constructors

Constructor and Description
Directory()

Method Summary

Modifier and Type	Method and Description
abstract void	close() Closes the store.
abstract OutputStream	createFile(String name) Creates a new, empty file in the directory with the given name.
abstract void	deleteFile(String name) Removes an existing file in the directory.
abstract boolean	fileExists(String name) Returns true iff a file with the given name exists.
abstract long	fileLength(String name) Returns the length of a file in the directory.
abstract long	fileModified(String name) Returns the time the named file was last modified.
abstract String[]	list() Returns an array of strings, one for each file in the directory.
abstract Lock	makeLock(String name) Construct a Lock.
abstract InputStream	openFile(String name) Returns a stream reading an existing file.
abstract void	renameFile(String from, String to) Renames an existing file in the directory.
abstract 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, toString, wait, wait, wait

Constructor Detail

Directory

public Directory()

Method Detail

list

public abstract String[] list()
                       throws IOException

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

Throws:

IOException

fileExists

public abstract boolean fileExists(String name)
                            throws IOException

Returns true iff a file with the given name exists.

Throws:

IOException

fileModified

public abstract long fileModified(String name)
                           throws IOException

Returns the time the named file was last modified.

Throws:

IOException

touchFile

public abstract void touchFile(String name)
                        throws IOException

Set the modified time of an existing file to now.

Throws:

IOException

deleteFile

public abstract void deleteFile(String name)
                         throws IOException

Removes an existing file in the directory.

Throws:

IOException

renameFile

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

Renames an existing file in the directory. If a file already exists with the new name, then it is replaced. This replacement should be atomic.

Throws:

IOException

fileLength

public abstract long fileLength(String name)
                         throws IOException

Returns the length of a file in the directory.

Throws:

IOException

createFile

public abstract OutputStream createFile(String name)
                                 throws IOException

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

Throws:

IOException

openFile

public abstract InputStream openFile(String name)
                              throws IOException

Returns a stream reading an existing file.

Throws:

IOException

makeLock

public abstract Lock makeLock(String name)

Construct a Lock.

Parameters:

name - the name of the lock file

close

public abstract void close()
                    throws IOException

Closes the store.

Throws:

IOException