org.terrier.structures.postings.integer

Class BlockFieldIntegerCodingIterablePosting

java.lang.Object

org.terrier.structures.postings.integer.BasicIntegerCodingIterablePosting

org.terrier.structures.postings.integer.FieldIntegerCodingIterablePosting

org.terrier.structures.postings.integer.BlockFieldIntegerCodingIterablePosting

All Implemented Interfaces:

Closeable, AutoCloseable, BlockPosting, FieldPosting, IterablePosting, Posting

public class BlockFieldIntegerCodingIterablePosting
extends FieldIntegerCodingIterablePosting
implements BlockPosting

An IterablePosting implementation, which can optionally support fields and/or blocks. Its content is compressed using some integer coding technique. Note: this class reads the input in chunks of posting. The chunk size is specified in chunkSize

Since:

4.0

Author:

Matteo Catena

Field Summary

Fields

Modifier and Type	Field and Description
protected int	bf
protected int[]	bfs
protected int[]	blocks
protected IntegerCodec	blocksCodec
protected int[]	blocksMatrix
protected int	hasBlocks

Fields inherited from class org.terrier.structures.postings.integer.FieldIntegerCodingIterablePosting

asFieldDocumentIndex, fields, fieldsCodec, fieldsCount, fieldsMatrix

Fields inherited from class org.terrier.structures.postings.integer.BasicIntegerCodingIterablePosting

blkCnt, chunkSize, currentPosting, decompressed, documentIndex, id, ids, idsCodec, input, logger, numberOfEntries, tf, tfs, tfsCodec

Fields inherited from interface org.terrier.structures.postings.IterablePosting

EOL

Constructor Summary

Constructors

Constructor and Description
BlockFieldIntegerCodingIterablePosting(ByteIn input, int numberOfEntries, DocumentIndex documentIndex, int chunkSize, int fieldCount, int hasBlocks, IntegerCodec idsCodec, IntegerCodec tfsCodec, IntegerCodec fieldsCodec, IntegerCodec blocksCodec)

Method Summary

Methods

Modifier and Type	Method and Description
WritablePosting	asWritablePosting() Copies this posting to one free of an iterator.
void	close()
protected void	decompress() This load the a chunk (tfs, fields and blocks (optionally)) and decompress it
protected void	get(int pos) Read the posting components from the chunk
long	getCurrentAddress()
int[]	getPositions() Return positions of occurrences
protected void	skip() If tfs, fields frequencies and blocks are not required, skip that part of the chunk
String	toString() Makes a human readable form of this posting

Methods inherited from class org.terrier.structures.postings.integer.FieldIntegerCodingIterablePosting

getFieldFrequencies, getFieldLengths, setFieldLengths

Methods inherited from class org.terrier.structures.postings.integer.BasicIntegerCodingIterablePosting

endOfPostings, getDocumentLength, getFrequency, getId, load, next, next, setId

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.terrier.structures.postings.Posting

getDocumentLength, getFrequency, getId, setId

Field Detail

bf

protected int bf

blocks

protected int[] blocks

bfs

protected int[] bfs

blocksMatrix

protected int[] blocksMatrix

blocksCodec

protected final IntegerCodec blocksCodec

hasBlocks

protected final int hasBlocks

Constructor Detail

BlockFieldIntegerCodingIterablePosting

public BlockFieldIntegerCodingIterablePosting(ByteIn input,
                                      int numberOfEntries,
                                      DocumentIndex documentIndex,
                                      int chunkSize,
                                      int fieldCount,
                                      int hasBlocks,
                                      IntegerCodec idsCodec,
                                      IntegerCodec tfsCodec,
                                      IntegerCodec fieldsCodec,
                                      IntegerCodec blocksCodec)
                                       throws IOException

Parameters:

input - the input channel

numberOfEntries - the number of postings

documentIndex - the document index

chunkSize - the size of the chunk

fieldCount - the number of fields (0 if the posting list has no fields)

hasBlocks - has this posting list posting positions? (0: no, 1:has positions, >1:has blocks)

idsCodec - the IntegerCodec to use to decode docIds

tfsCodec - the IntegerCodec to use to decode term frequencies

fieldsCodec - the IntegerCodec to use to decode field frequencies (if any, null otherwise)

blocksCodec - the IntegerCodec to use to decode blocks (if any, null otherwise)

Throws:

IOException

Method Detail

asWritablePosting

public WritablePosting asWritablePosting()

Description copied from interface: Posting

Copies this posting to one free of an iterator. Kind of like a clone.

Specified by:

asWritablePosting in interface Posting

Overrides:

asWritablePosting in class FieldIntegerCodingIterablePosting

Returns:

an identical posting, but which can be maniulated free of this iterator

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class BasicIntegerCodingIterablePosting

Throws:

IOException

decompress

protected final void decompress()
                         throws IOException

This load the a chunk (tfs, fields and blocks (optionally)) and decompress it

Overrides:

decompress in class FieldIntegerCodingIterablePosting

Throws:

IOException

skip

protected final void skip()
                   throws IOException

If tfs, fields frequencies and blocks are not required, skip that part of the chunk

Overrides:

skip in class FieldIntegerCodingIterablePosting

Throws:

IOException

get

protected final void get(int pos)
                  throws IOException

Read the posting components from the chunk

Overrides:

get in class FieldIntegerCodingIterablePosting

Parameters:

pos - the posting to load (as index in the internal arrays)

Throws:

IOException

getPositions

public int[] getPositions()

Description copied from interface: BlockPosting

Return positions of occurrences

Specified by:

getPositions in interface BlockPosting

toString

public String toString()

Makes a human readable form of this posting

Overrides:

toString in class FieldIntegerCodingIterablePosting

getCurrentAddress

public long getCurrentAddress()

Overrides:

getCurrentAddress in class BasicIntegerCodingIterablePosting