org.apache.lucene.store
Class IndexOutput

java.lang.Object
  org.apache.lucene.store.IndexOutput

Direct Known Subclasses:

BufferedIndexOutput, ChecksumIndexOutput, DbIndexOutput, JEIndexOutput, RAMOutputStream

public abstract class IndexOutput
extends Object

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

See Also:

Directory, IndexInput

Constructor Summary

IndexOutput()

Method Summary

abstract void	close() Closes this stream to further operations.
void	copyBytes(IndexInput input, long numBytes) Copy numBytes bytes from input to ourself.
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) Sets current position in this file, where the next write will occur.
void	setLength(long length) Set the file length.
abstract void	writeByte(byte b) Writes a single byte.
void	writeBytes(byte[] b, int length) Writes an array of bytes.
abstract void	writeBytes(byte[] b, int offset, int length) Writes an array of bytes.
void	writeChars(char[] s, int start, int length) Deprecated. -- please pre-convert to utf8 bytes instead or use writeString(java.lang.String)
void	writeChars(String s, int start, int length) Deprecated. -- please pre-convert to utf8 bytes instead or use writeString(java.lang.String)
void	writeInt(int i) Writes an int as four bytes.
void	writeLong(long i) Writes a long as eight bytes.
void	writeString(String s) Writes a string.
void	writeVInt(int i) Writes an int in a variable-length format.
void	writeVLong(long i) Writes an long in a variable-length format.

Methods inherited from class java.lang.Object

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

Constructor Detail

IndexOutput

public IndexOutput()

Method Detail

writeByte

public abstract void writeByte(byte b)
                        throws IOException

Writes a single byte.

Throws:

IOException

See Also:

IndexInput.readByte()

writeBytes

public void writeBytes(byte[] b,
                       int length)
                throws IOException

Writes an array of bytes.

Parameters:

b - the bytes to write

length - the number of bytes to write

Throws:

IOException

See Also:

IndexInput.readBytes(byte[],int,int)

writeBytes

public abstract void writeBytes(byte[] b,
                                int offset,
                                int length)
                         throws IOException

Writes an array of bytes.

Parameters:

b - the bytes to write

offset - the offset in the byte array

length - the number of bytes to write

Throws:

IOException

See Also:

IndexInput.readBytes(byte[],int,int)

writeInt

public void writeInt(int i)
              throws IOException

Writes an int as four bytes.

Throws:

IOException

See Also:

IndexInput.readInt()

writeVInt

public void writeVInt(int i)
               throws IOException

Writes an int in a variable-length format. Writes between one and five bytes. Smaller values take fewer bytes. Negative numbers are not supported.

Throws:

IOException

See Also:

IndexInput.readVInt()

writeLong

public void writeLong(long i)
               throws IOException

Writes a long as eight bytes.

Throws:

IOException

See Also:

IndexInput.readLong()

writeVLong

public void writeVLong(long i)
                throws IOException

Writes an long in a variable-length format. Writes between one and five bytes. Smaller values take fewer bytes. Negative numbers are not supported.

Throws:

IOException

See Also:

IndexInput.readVLong()

writeString

public void writeString(String s)
                 throws IOException

Writes a string.

Throws:

IOException

See Also:

IndexInput.readString()

writeChars

public void writeChars(String s,
                       int start,
                       int length)
                throws IOException

Deprecated. -- please pre-convert to utf8 bytes instead or use writeString(java.lang.String)

Writes a sub sequence of characters from s as the old format (modified UTF-8 encoded bytes).

Parameters:

s - the source of the characters

start - the first character in the sequence

length - the number of characters in the sequence

Throws:

IOException

writeChars

public void writeChars(char[] s,
                       int start,
                       int length)
                throws IOException

Deprecated. -- please pre-convert to utf8 bytes instead or use writeString(java.lang.String)

Writes a sub sequence of characters from char[] as the old format (modified UTF-8 encoded bytes).

Parameters:

s - the source of the characters

start - the first character in the sequence

length - the number of characters in the sequence

Throws:

IOException

copyBytes

public void copyBytes(IndexInput input,
                      long numBytes)
               throws IOException

Copy numBytes bytes from input to ourself.

Throws:

IOException

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.

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

public abstract void seek(long pos)
                   throws IOException

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