org.apache.lucene.store

Class RAMDirectory

java.lang.Object

org.apache.lucene.store.Directory

org.apache.lucene.store.RAMDirectory

All Implemented Interfaces:

java.io.Serializable

public class RAMDirectory
extends Directory
implements java.io.Serializable

A memory-resident Directory implementation. Locking implementation is by default the SingleInstanceLockFactory but can be changed with Directory.setLockFactory(org.apache.lucene.store.LockFactory).

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
RAMDirectory() Constructs an empty Directory.
RAMDirectory(Directory dir) Creates a new RAMDirectory instance from a different Directory implementation.
RAMDirectory(java.io.File dir) Creates a new RAMDirectory instance from the FSDirectory.
RAMDirectory(java.lang.String dir) Creates a new RAMDirectory instance from the FSDirectory.

Method Summary

Modifier and Type	Method and Description
void	close() Closes the store to future operations, releasing associated memory.
IndexOutput	createOutput(java.lang.String name) Creates a new, empty file in the directory with the given name.
void	deleteFile(java.lang.String name) Removes an existing file in the directory.
boolean	fileExists(java.lang.String name) Returns true iff the named file exists in this directory.
long	fileLength(java.lang.String name) Returns the length in bytes of a file in the directory.
long	fileModified(java.lang.String name) Returns the time the named file was last modified.
java.lang.String[]	list() Returns an array of strings, one for each file in the directory.
IndexInput	openInput(java.lang.String name) Returns a stream reading an existing file.
void	renameFile(java.lang.String from, java.lang.String to) Deprecated.
long	sizeInBytes() Return total size in bytes of all files in this directory.
void	touchFile(java.lang.String name) Set the modified time of an existing file to now.

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

clearLock, copy, getLockFactory, getLockID, makeLock, openInput, setLockFactory

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RAMDirectory

public RAMDirectory()

Constructs an empty Directory.

RAMDirectory

public RAMDirectory(Directory dir)
             throws java.io.IOException

Creates a new RAMDirectory instance from a different Directory implementation. This can be used to load a disk-based index into memory.

This should be used only with indices that can fit into memory.

Note that the resulting RAMDirectory instance is fully independent from the original Directory (it is a complete copy). Any subsequent changes to the original Directory will not be visible in the RAMDirectory instance.

Parameters:

dir - a Directory value

Throws:

java.io.IOException - if an error occurs

RAMDirectory

public RAMDirectory(java.io.File dir)
             throws java.io.IOException

Creates a new RAMDirectory instance from the FSDirectory.

Parameters:

dir - a File specifying the index directory

Throws:

java.io.IOException

See Also:

RAMDirectory(Directory)

RAMDirectory

public RAMDirectory(java.lang.String dir)
             throws java.io.IOException

Creates a new RAMDirectory instance from the FSDirectory.

Parameters:

dir - a String specifying the full index directory path

Throws:

java.io.IOException

See Also:

RAMDirectory(Directory)

Method Detail

list

public final java.lang.String[] list()

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

Specified by:

list in class Directory

fileExists

public final boolean fileExists(java.lang.String name)

Returns true iff the named file exists in this directory.

Specified by:

fileExists in class Directory

fileModified

public final long fileModified(java.lang.String name)
                        throws java.io.IOException

Returns the time the named file was last modified.

Specified by:

fileModified in class Directory

Throws:

java.io.IOException - if the file does not exist

touchFile

public void touchFile(java.lang.String name)
               throws java.io.IOException

Set the modified time of an existing file to now.

Specified by:

touchFile in class Directory

Throws:

java.io.IOException - if the file does not exist

fileLength

public final long fileLength(java.lang.String name)
                      throws java.io.IOException

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

Specified by:

fileLength in class Directory

Throws:

java.io.IOException - if the file does not exist

sizeInBytes

public final long sizeInBytes()

Return total size in bytes of all files in this directory. This is currently quantized to RAMOutputStream.BUFFER_SIZE.

deleteFile

public void deleteFile(java.lang.String name)
                throws java.io.IOException

Removes an existing file in the directory.

Specified by:

deleteFile in class Directory

Throws:

java.io.IOException - if the file does not exist

renameFile

public final void renameFile(java.lang.String from,
                             java.lang.String to)
                      throws java.io.IOException

Deprecated.

Renames an existing file in the directory.

Specified by:

renameFile in class Directory

Throws:

java.io.FileNotFoundException - if from does not exist

java.io.IOException

createOutput

public IndexOutput createOutput(java.lang.String name)
                         throws java.io.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:

java.io.IOException

openInput

public IndexInput openInput(java.lang.String name)
                     throws java.io.IOException

Returns a stream reading an existing file.

Specified by:

openInput in class Directory

Throws:

java.io.IOException

close

public void close()

Closes the store to future operations, releasing associated memory.

Specified by:

close in class Directory