org.terrier.structures.indexing.singlepass

Class BlockPostingInRun

java.lang.Object

org.terrier.structures.indexing.singlepass.PostingInRun

org.terrier.structures.indexing.singlepass.SimplePostingInRun

org.terrier.structures.indexing.singlepass.BlockPostingInRun

Direct Known Subclasses:

BlockFieldPostingInRun

public class BlockPostingInRun
extends SimplePostingInRun

Class holding the information for a posting list read from a previously written run at disk. Used in the merging phase of the Single pass inversion method. This class knows how to append itself to a BitOut and it represents a posting with blocks information (tf, df, [docid, idf, blockFr [blockid]])

Author:

Roi Blanco

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected class	BlockPostingInRun.BlockPIRPostingIterator

Nested classes/interfaces inherited from class org.terrier.structures.indexing.singlepass.SimplePostingInRun

SimplePostingInRun.PIRPostingIterator

Field Summary

Fields inherited from class org.terrier.structures.indexing.singlepass.PostingInRun

postingSource, term, termDf, termTF

Constructor Summary

Constructors

Constructor and Description
BlockPostingInRun() Constructor for the class.

Method Summary

Methods

Modifier and Type	Method and Description
int	append(BitOut bos, int last, int runShift) Writes the document data of this posting to a BitOut It encodes the data with the right compression methods.
IterablePosting	getPostingIterator(int runShift) Returns an IterablePosting object for the postings in this run

Methods inherited from class org.terrier.structures.indexing.singlepass.PostingInRun

addToLexiconEntry, append, getDf, getLexiconEntry, getTerm, getTF, setDf, setPostingSource, setTerm, setTF

Methods inherited from class java.lang.Object

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

Constructor Detail

BlockPostingInRun

public BlockPostingInRun()

Constructor for the class.

Method Detail

append

public int append(BitOut bos,
         int last,
         int runShift)
           throws IOException

Writes the document data of this posting to a BitOut It encodes the data with the right compression methods. The stream is written as d1, idf(d1), blockNo(d1), bid1, bid2, ..., d2 - d1, idf(d2), blockNo(d2), ... etc

Overrides:

append in class SimplePostingInRun

Parameters:

bos - BitOut to be written.

last - int representing the last document written in this posting.

runShift - amount of delta to apply to the first posting read.

Returns:

The last posting written.

Throws:

IOException

getPostingIterator

public IterablePosting getPostingIterator(int runShift)
                                   throws IOException

Description copied from class: PostingInRun

Returns an IterablePosting object for the postings in this run

Overrides:

getPostingIterator in class SimplePostingInRun

Throws:

IOException