Package org.apache.lucene.store

Class IndexOutput

java.lang.Object

org.apache.lucene.store.DataOutput

org.apache.lucene.store.IndexOutput

All Implemented Interfaces:

Closeable, AutoCloseable

Direct Known Subclasses:

BufferedIndexOutput, ChecksumIndexOutput, RAMOutputStream

public abstract class IndexOutput
extends DataOutput
implements Closeable

Abstract base class for output to a file in a Directory. A random-access output stream. Used for all Lucene index output operations.

IndexOutput may only be used from one thread, because it is not thread safe (it keeps internal state like file position).

See Also:

• Directory
• IndexInput

Constructor Summary

Constructors

Constructor	Description
IndexOutput()

Method Summary

Modifier and Type	Method	Description
abstract void	close()	Closes this stream to further operations.
abstract void	flush()	Forces any buffered output to be written.
abstract long	getFilePointer()	Returns the current position in this file, where the next write will occur.
abstract long	length()	The number of bytes in the file.
abstract void	seek(long pos)	Deprecated. (4.1) This method will be removed in Lucene 5.0
void	setLength(long length)	Set the file length.

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

copyBytes, writeByte, writeBytes, writeBytes, writeInt, writeLong, writeShort, writeString, writeStringSet, writeStringStringMap, writeVInt, writeVLong

Methods inherited from class java.lang.Object

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

Constructor Details

IndexOutput

public IndexOutput()

Method Details

flush

public abstract void flush()
                    throws IOException

Forces any buffered output to be written.

Throws:

IOException

close

public abstract void close()
                    throws IOException

Closes this stream to further operations.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Throws:

IOException

getFilePointer

public abstract long getFilePointer()

Returns the current position in this file, where the next write will occur.

See Also:

• seek(long)

seek

@Deprecated
public abstract void seek(long pos)
                   throws IOException

Deprecated.

(4.1) This method will be removed in Lucene 5.0

Sets current position in this file, where the next write will occur.

Throws:

IOException

See Also:

• getFilePointer()

length

public abstract long length()
                     throws IOException

The number of bytes in the file.

Throws:

IOException

setLength

public void setLength(long length)
               throws IOException

Set the file length. By default, this method does nothing (it's optional for a Directory to implement it). But, certain Directory implementations (for example @see FSDirectory) can use this to inform the underlying IO system to pre-allocate the file to the specified size. If the length is longer than the current file length, the bytes added to the file are undefined. Otherwise the file is truncated.

Parameters:

length - file length

Throws:

IOException