Package org.apache.lucene.store

Class ByteBuffersDirectory

java.lang.Object

org.apache.lucene.store.Directory

org.apache.lucene.store.BaseDirectory

org.apache.lucene.store.ByteBuffersDirectory

All Implemented Interfaces:

Closeable, AutoCloseable

public final class ByteBuffersDirectory
extends BaseDirectory

A ByteBuffer-based Directory implementation that can be used to store index files on the heap.

Important: Note that MMapDirectory is nearly always a better choice as it uses OS caches more effectively (through memory-mapped buffers). A heap-based directory like this one can have the advantage in case of ephemeral, small, short-lived indexes when disk syncs provide an additional overhead.

WARNING: This API is experimental and might change in incompatible ways in the next release.

Field Summary

Fields

Modifier and Type	Field	Description
static final BiFunction<String,ByteBuffersDataOutput,IndexInput>	OUTPUT_AS_BYTE_ARRAY
static final BiFunction<String,ByteBuffersDataOutput,IndexInput>	OUTPUT_AS_MANY_BUFFERS
static final BiFunction<String,ByteBuffersDataOutput,IndexInput>	OUTPUT_AS_MANY_BUFFERS_LUCENE
static final BiFunction<String,ByteBuffersDataOutput,IndexInput>	OUTPUT_AS_ONE_BUFFER

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

isOpen, lockFactory

Constructor Summary

Constructors

Constructor	Description
ByteBuffersDirectory()
ByteBuffersDirectory(LockFactory lockFactory)
ByteBuffersDirectory(LockFactory factory, Supplier<ByteBuffersDataOutput> bbOutputSupplier, BiFunction<String,ByteBuffersDataOutput,IndexInput> outputToInput)

Method Summary

Modifier and Type	Method	Description
void	close()	Closes the directory.
IndexOutput	createOutput(String name, IOContext context)	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)	Creates a new, empty, temporary file in the directory and returns an IndexOutput instance for appending data to this file.
void	deleteFile(String name)	Removes an existing file in the directory.
boolean	fileExists(String name)
long	fileLength(String name)	Returns the byte length of a file in the directory.
Set<String>	getPendingDeletions()	Returns a set of files currently pending deletion in this directory.
String[]	listAll()	Returns names of all files stored in this directory.
IndexInput	openInput(String name, IOContext context)	Opens a stream for reading an existing file.
void	rename(String source, String dest)	Renames source file to dest file where dest must not already exist in the directory.
void	sync(Collection<String> names)	Ensures that any writes to these files are moved to stable storage (made durable).
void	syncMetaData()	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 Details

OUTPUT_AS_MANY_BUFFERS

public static final BiFunction<String,ByteBuffersDataOutput,IndexInput> OUTPUT_AS_MANY_BUFFERS

OUTPUT_AS_ONE_BUFFER

public static final BiFunction<String,ByteBuffersDataOutput,IndexInput> OUTPUT_AS_ONE_BUFFER

OUTPUT_AS_BYTE_ARRAY

public static final BiFunction<String,ByteBuffersDataOutput,IndexInput> OUTPUT_AS_BYTE_ARRAY

OUTPUT_AS_MANY_BUFFERS_LUCENE

public static final BiFunction<String,ByteBuffersDataOutput,IndexInput> OUTPUT_AS_MANY_BUFFERS_LUCENE

Constructor Details

ByteBuffersDirectory

public ByteBuffersDirectory()

ByteBuffersDirectory

public ByteBuffersDirectory(LockFactory lockFactory)

ByteBuffersDirectory

public ByteBuffersDirectory(LockFactory factory,
 Supplier<ByteBuffersDataOutput> bbOutputSupplier,
 BiFunction<String,ByteBuffersDataOutput,IndexInput> outputToInput)

Method Details

listAll

public String[] listAll()
                 throws IOException

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

Throws:

IOException - in case of I/O error

deleteFile

public void deleteFile(String name)
                throws IOException

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

fileLength

public long fileLength(String name)
                throws IOException

Description copied from class: Directory

Returns the byte length of a file in the directory.

This method must throw either NoSuchFileException or FileNotFoundException if name points to a non-existing file.

Specified by:

fileLength in class Directory

Parameters:

name - the name of an existing file.

Throws:

IOException - in case of I/O error

fileExists

public boolean fileExists(String name)

createOutput

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

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

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

rename

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

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

sync

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

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()

syncMetaData

public void syncMetaData()
                  throws IOException

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

Description copied from class: Directory

Opens a stream for reading an existing file.

This method must throw either NoSuchFileException or FileNotFoundException if name points to a non-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()
           throws IOException

Description copied from class: Directory

Closes the directory.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in class Directory

Throws:

IOException

getPendingDeletions

public Set<String> getPendingDeletions()

Description copied from class: Directory

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

Specified by:

getPendingDeletions in class Directory