org.sindice.siren.index.codecs.block

Class BlockIndexOutput.BlockWriter

java.lang.Object

org.sindice.siren.index.codecs.block.BlockIndexOutput.BlockWriter

Direct Known Subclasses:

DocsFreqBlockIndexOutput.DocsFreqBlockWriter, NodBlockIndexOutput.NodBlockWriter, PosBlockIndexOutput.PosBlockWriter

Enclosing class:

BlockIndexOutput

protected abstract class BlockIndexOutput.BlockWriter
extends Object

Abstraction over the writer of the blocks of the postings file.

The abstraction provides an interface to write and flush blocks. Subclasses must implement the encoding of the block header and the encoding of the block data.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	BlockIndexOutput.BlockWriter()

Method Summary

Methods

Modifier and Type	Method and Description
protected abstract void	compress() Compress the data block
void	flush() Flush of pending data block to the output file.
protected int	getMinimumBufferSize(int bufferSize, int windowSize) Compute the minimum size of a buffer based on the required size and the compression window size.
protected abstract void	initBlock() Init writer for new block
abstract boolean	isEmpty()
abstract boolean	isFull()
protected void	writeBlock() Write data block to the output file with the following sequence of operations: Compress the data Write block header (as header can depend on statistic computed from data compression) Write compressed data block Reset writer for new block
protected abstract void	writeData() Write compressed data block to the output file
protected abstract void	writeHeader() Write block header to the output file

Methods inherited from class java.lang.Object

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

Constructor Detail

BlockIndexOutput.BlockWriter

protected BlockIndexOutput.BlockWriter()

Method Detail

flush

public void flush()
           throws IOException

Flush of pending data block to the output file.

Throws:

IOException

writeBlock

protected void writeBlock()
                   throws IOException

Write data block to the output file with the following sequence of operations:

• Compress the data
• Write block header (as header can depend on statistic computed from data compression)
• Write compressed data block
• Reset writer for new block

Throws:

IOException

isEmpty

public abstract boolean isEmpty()

isFull

public abstract boolean isFull()

compress

protected abstract void compress()

Compress the data block

writeHeader

protected abstract void writeHeader()
                             throws IOException

Write block header to the output file

Throws:

IOException

writeData

protected abstract void writeData()
                           throws IOException

Write compressed data block to the output file

Throws:

IOException

initBlock

protected abstract void initBlock()

Init writer for new block

getMinimumBufferSize

protected int getMinimumBufferSize(int bufferSize,
                       int windowSize)

Compute the minimum size of a buffer based on the required size and the compression window size.