org.apache.lucene.store

Class CompoundFileDirectory

java.lang.Object

org.apache.lucene.store.Directory

org.apache.lucene.store.BaseDirectory

org.apache.lucene.store.CompoundFileDirectory

All Implemented Interfaces:

Closeable, AutoCloseable

public final class CompoundFileDirectory
extends BaseDirectory

Class for accessing a compound stream. This class implements a directory, but is limited to only read operations. Directory methods that would normally modify data throw an exception.

All files belonging to a segment have the same name with varying extensions. The extensions correspond to the different file formats used by the Codec. When using the Compound File format these files are collapsed into a single .cfs file (except for the LiveDocsFormat, with a corresponding .cfe file indexing its sub-files.

Files:

• .cfs: An optional "virtual" file consisting of all the other index files for systems that frequently run out of file handles.
• .cfe: The "virtual" compound file's entry table holding all entries in the corresponding .cfs file.

Description:

• Compound (.cfs) --> Header, FileData ^FileCount
• Compound Entry Table (.cfe) --> Header, FileCount, <FileName, DataOffset, DataLength> ^FileCount, Footer
• Header --> CodecHeader
• FileCount --> VInt
• DataOffset,DataLength --> UInt64
• FileName --> String
• FileData --> raw file data
• Footer --> CodecFooter

Notes:

• FileCount indicates how many files are contained in this compound file. The entry table that follows has that many entries.
• Each directory entry contains a long pointer to the start of this file's data section, the files length, and a String with that file's name.

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

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	CompoundFileDirectory.FileEntry Offset/Length for a slice inside of a compound file

Field Summary

Fields

Modifier and Type	Field and Description
protected int	readBufferSize

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

isOpen, lockFactory

Constructor Summary

Constructors

Constructor and Description
CompoundFileDirectory(Directory directory, String fileName, IOContext context, boolean openForWrite) Create a new CompoundFileDirectory.

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Closes the store.
IndexOutput	createOutput(String name, IOContext context) Creates a new, empty file in the directory with the given name.
void	deleteFile(String name) Not implemented
boolean	fileExists(String name) Returns true iff a file with the given name exists.
long	fileLength(String name) Returns the length of a file in the directory.
Directory	getDirectory()
String	getName()
String[]	listAll() Returns an array of strings, one for each file in the directory.
Lock	makeLock(String name) Not implemented
IndexInput	openInput(String name, IOContext context) Returns a stream reading an existing file, with the specified read buffer size.
void	renameFile(String from, String to) Not implemented
void	sync(Collection<String> names) Ensure that any writes to these files are moved to stable storage.
String	toString()

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

clearLock, ensureOpen, getLockFactory, setLockFactory

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

copy, getLockID, openChecksumInput

Methods inherited from class java.lang.Object

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

Field Detail

readBufferSize

protected final int readBufferSize

Constructor Detail

CompoundFileDirectory

public CompoundFileDirectory(Directory directory,
                     String fileName,
                     IOContext context,
                     boolean openForWrite)
                      throws IOException

Create a new CompoundFileDirectory.

Throws:

IOException

Method Detail

getDirectory

public Directory getDirectory()

getName

public String getName()

close

public void close()
           throws IOException

Description copied from class: Directory

Closes the store.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in class Directory

Throws:

IOException

openInput

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

Description copied from class: Directory

Returns a stream reading an existing file, with the specified read buffer size. The particular Directory implementation may ignore the buffer size. Currently the only Directory implementations that respect this parameter are FSDirectory and CompoundFileDirectory.

Throws FileNotFoundException or NoSuchFileException if the file does not exist.

Specified by:

openInput in class Directory

Throws:

IOException

listAll

public String[] listAll()

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

Specified by:

listAll in class Directory

fileExists

public boolean fileExists(String name)

Returns true iff a file with the given name exists.

Specified by:

fileExists in class Directory

deleteFile

public void deleteFile(String name)

Not implemented

Specified by:

deleteFile in class Directory

Throws:

UnsupportedOperationException - always: not supported by CFS

renameFile

public void renameFile(String from,
              String to)

Not implemented

Throws:

UnsupportedOperationException - always: not supported by CFS

fileLength

public long fileLength(String name)
                throws IOException

Returns the length of a file in the directory.

Specified by:

fileLength in class Directory

Parameters:

name - the name of the file for which to return the length.

Throws:

IOException - if the file does not exist

createOutput

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

Description copied from class: Directory

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:

IOException

sync

public void sync(Collection<String> names)

Description copied from class: Directory

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

NOTE: Clients may call this method for same files over and over again, so some impls might optimize for that. For other impls the operation can be a noop, for various reasons.

Specified by:

sync in class Directory

makeLock

public Lock makeLock(String name)

Not implemented

Overrides:

makeLock in class BaseDirectory

Parameters:

name - the name of the lock file

Throws:

UnsupportedOperationException - always: not supported by CFS

toString

public String toString()

Overrides:

toString in class Directory