org.apache.lucene.store

Class RAMDirectory

java.lang.Object

org.apache.lucene.store.Directory

org.apache.lucene.store.BaseDirectory

org.apache.lucene.store.RAMDirectory

All Implemented Interfaces:

Closeable, AutoCloseable, Accountable

Deprecated.

This class uses inefficient synchronization and is discouraged in favor of MMapDirectory. It will be removed in future versions of Lucene.

@Deprecated
public class RAMDirectory
extends BaseDirectory
implements Accountable

A memory-resident Directory implementation. Locking implementation is by default the SingleInstanceLockFactory.

Warning: This class is not intended to work with huge indexes. Everything beyond several hundred megabytes will waste resources (GC cycles), because it uses an internal buffer size of 1024 bytes, producing millions of byte[1024] arrays. This class is optimized for small memory-resident indexes. It also has bad concurrency on multithreaded environments.

It is recommended to materialize large indexes on disk and use MMapDirectory, which is a high-performance directory implementation working directly on the file system cache of the operating system, so copying data to Java heap space is not useful.

Field Summary

Fields

Modifier and Type	Field and Description
protected Map<String,RAMFile>	fileMap Deprecated.
protected AtomicLong	sizeInBytes Deprecated.

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

isOpen, lockFactory

Constructor Summary

Constructors

Constructor and Description
RAMDirectory() Deprecated. Constructs an empty Directory.
RAMDirectory(FSDirectory dir, IOContext context) Deprecated. Creates a new RAMDirectory instance from a different Directory implementation.
RAMDirectory(LockFactory lockFactory) Deprecated. Constructs an empty Directory with the given LockFactory.

Method Summary

Modifier and Type	Method and Description
void	close() Deprecated. Closes the store to future operations, releasing associated memory.
IndexOutput	createOutput(String name, IOContext context) Deprecated. Creates a new, empty file in the directory and returns an IndexOutput instance for appending data to this file.
IndexOutput	createTempOutput(String prefix, String suffix, IOContext context) Deprecated. Creates a new, empty, temporary file in the directory and returns an IndexOutput instance for appending data to this file.
void	deleteFile(String name) Deprecated. Removes an existing file in the directory.
long	fileLength(String name) Deprecated. Returns the length in bytes of a file in the directory.
boolean	fileNameExists(String name) Deprecated.
Collection<Accountable>	getChildResources() Deprecated. Returns nested resources of this class.
Set<String>	getPendingDeletions() Deprecated. Returns a set of files currently pending deletion in this directory.
String[]	listAll() Deprecated. Returns names of all files stored in this directory.
protected RAMFile	newRAMFile() Deprecated. Returns a new RAMFile for storing data.
IndexInput	openInput(String name, IOContext context) Deprecated. Returns a stream reading an existing file.
long	ramBytesUsed() Deprecated. Return total size in bytes of all files in this directory.
void	rename(String source, String dest) Deprecated. Renames source file to dest file where dest must not already exist in the directory.
void	sync(Collection<String> names) Deprecated. Ensures that any writes to these files are moved to stable storage (made durable).
void	syncMetaData() Deprecated. Ensures that directory metadata, such as recent file renames, are moved to stable storage.

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

ensureOpen, obtainLock, toString

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

copyFrom, getTempFileName, openChecksumInput

Methods inherited from class java.lang.Object

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

Field Detail

fileMap

protected final Map<String,RAMFile> fileMap

Deprecated.

sizeInBytes

protected final AtomicLong sizeInBytes

Deprecated.

Constructor Detail

RAMDirectory

public RAMDirectory()

Deprecated.

Constructs an empty Directory.

RAMDirectory

public RAMDirectory(LockFactory lockFactory)

Deprecated.

Constructs an empty Directory with the given LockFactory.

RAMDirectory

public RAMDirectory(FSDirectory dir,
                    IOContext context)
             throws IOException

Deprecated.

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

Warning: This class is not intended to work with huge indexes. Everything beyond several hundred megabytes will waste resources (GC cycles), because it uses an internal buffer size of 1024 bytes, producing millions of byte[1024] arrays. This class is optimized for small memory-resident indexes. It also has bad concurrency on multithreaded environments.

For disk-based indexes it is recommended to use MMapDirectory, which is a high-performance directory implementation working directly on the file system cache of the operating system, so copying data to Java heap space is not useful.

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:

IOException - if an error occurs

Method Detail

listAll

public final String[] listAll()

Deprecated.

Description copied from class: Directory

Returns names of all files stored in this directory. The output must be in sorted (UTF-16, java's String.compareTo(java.lang.String)) order.

Specified by:

listAll in class Directory

fileNameExists

public final boolean fileNameExists(String name)

Deprecated.

fileLength

public final long fileLength(String name)
                      throws IOException

Deprecated.

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

Specified by:

fileLength in class Directory

Parameters:

name - the name of an existing file.

Throws:

IOException - if the file does not exist

ramBytesUsed

public final long ramBytesUsed()

Deprecated.

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

Specified by:

ramBytesUsed in interface Accountable

getChildResources

public Collection<Accountable> getChildResources()

Deprecated.

Description copied from interface: Accountable

Returns nested resources of this class. The result should be a point-in-time snapshot (to avoid race conditions).

Specified by:

getChildResources in interface Accountable

See Also:

Accountables

deleteFile

public void deleteFile(String name)
                throws IOException

Deprecated.

Description copied from class: Directory

Removes an existing file in the directory. This method must throw either NoSuchFileException or FileNotFoundException if name points to a non-existing file.

Specified by:

deleteFile in class Directory

Parameters:

name - the name of an existing file.

Throws:

IOException - in case of I/O error

createOutput

public IndexOutput createOutput(String name,
                                IOContext context)
                         throws IOException

Deprecated.

Description copied from class: Directory

Creates a new, empty file in the directory and returns an IndexOutput instance for appending data to this file. This method must throw FileAlreadyExistsException if the file already exists.

Specified by:

createOutput in class Directory

Parameters:

name - the name of the file to create.

Throws:

IOException - in case of I/O error

createTempOutput

public IndexOutput createTempOutput(String prefix,
                                    String suffix,
                                    IOContext context)
                             throws IOException

Deprecated.

Description copied from class: Directory

Creates a new, empty, temporary file in the directory and returns an IndexOutput instance for appending data to this file. The temporary file name (accessible via IndexOutput.getName()) will start with prefix, end with suffix and have a reserved file extension .tmp.

Specified by:

createTempOutput in class Directory

Throws:

IOException

newRAMFile

protected RAMFile newRAMFile()

Deprecated.

Returns a new RAMFile for storing data. This method can be overridden to return different RAMFile impls, that e.g. override RAMFile.newBuffer(int).

sync

public void sync(Collection<String> names)
          throws IOException

Deprecated.

Description copied from class: Directory

Ensures that any writes to these files are moved to stable storage (made durable). Lucene uses this to properly commit changes to the index, to prevent a machine/OS crash from corrupting the index.

Specified by:

sync in class Directory

Throws:

IOException

See Also:

Directory.syncMetaData()

rename

public void rename(String source,
                   String dest)
            throws IOException

Deprecated.

Description copied from class: Directory

Renames source file to dest file where dest must not already exist in the directory. It is permitted for this operation to not be truly atomic, for example both source and dest can be visible temporarily in Directory.listAll(). However, the implementation of this method must ensure the content of dest appears as the entire source atomically. So once dest is visible for readers, the entire content of previous source is visible. This method is used by IndexWriter to publish commits.

Specified by:

rename in class Directory

Throws:

IOException

syncMetaData

public void syncMetaData()
                  throws IOException

Deprecated.

Description copied from class: Directory

Ensures that directory metadata, such as recent file renames, are moved to stable storage.

Specified by:

syncMetaData in class Directory

Throws:

IOException

See Also:

Directory.sync(Collection)

openInput

public IndexInput openInput(String name,
                            IOContext context)
                     throws IOException

Deprecated.

Returns a stream reading an existing file.

Specified by:

openInput in class Directory

Parameters:

name - the name of an existing file.

Throws:

IOException - in case of I/O error

close

public void close()

Deprecated.

Closes the store to future operations, releasing associated memory.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in class Directory

getPendingDeletions

public Set<String> getPendingDeletions()

Deprecated.

Description copied from class: Directory

Returns a set of files currently pending deletion in this directory.

Specified by:

getPendingDeletions in class Directory