org.terrier.structures
Class BlockInvertedIndex

java.lang.Object
  org.terrier.structures.BitPostingIndex
      org.terrier.structures.InvertedIndex
          org.terrier.structures.BlockInvertedIndex

All Implemented Interfaces:

java.io.Closeable, IndexConfigurable, PostingIndex<BitIndexPointer>

public class BlockInvertedIndex
extends InvertedIndex
implements IndexConfigurable

This class implements the block field inverted index for performing retrieval.

Author:

Douglas Johnson, Craig Macdonald et al.

Field Summary

protected int

DocumentBlockCountDelta

Fields inherited from class org.terrier.structures.InvertedIndex

doi, FIELD_LOAD_FACTOR, logger, NORMAL_LOAD_FACTOR

Fields inherited from class org.terrier.structures.BitPostingIndex

fieldCount, file, index, postingConstructor, postingImplementation

Constructor Summary

BlockInvertedIndex(Index index, java.lang.String structureName)
Constructs an instance of the class with

BlockInvertedIndex(Index index, java.lang.String structureName, DocumentIndex doi)
Constructs an instance of the class with

BlockInvertedIndex(Index index, java.lang.String structureName, DocumentIndex _doi, java.lang.Class<? extends IterablePosting> postingClass)
Constructs an instance of the class with

Method Summary

int[][]	getDocuments(BitIndexPointer pointer) Returns a 2D array containing the document ids, the term frequencies, the field scores the block frequencies and the block ids for the given documents.
void	setIndex(Index i) let it know which index to use

Methods inherited from class org.terrier.structures.InvertedIndex

getBitFiles, getDocuments, getPostings, print

Methods inherited from class org.terrier.structures.BitPostingIndex

close

Methods inherited from class java.lang.Object

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

Field Detail

DocumentBlockCountDelta

protected int DocumentBlockCountDelta

Constructor Detail

BlockInvertedIndex

public BlockInvertedIndex(Index index,
                          java.lang.String structureName,
                          DocumentIndex _doi,
                          java.lang.Class<? extends IterablePosting> postingClass)
                   throws java.io.IOException

Constructs an instance of the class with

Parameters:

index -

structureName -

_doi -

postingClass -

Throws:

java.io.IOException

BlockInvertedIndex

public BlockInvertedIndex(Index index,
                          java.lang.String structureName,
                          DocumentIndex doi)
                   throws java.io.IOException

Constructs an instance of the class with

Parameters:

index -

structureName -

doi -

Throws:

java.io.IOException

BlockInvertedIndex

public BlockInvertedIndex(Index index,
                          java.lang.String structureName)
                   throws java.io.IOException

Constructs an instance of the class with

Parameters:

index -

structureName -

Throws:

java.io.IOException

Method Detail

setIndex

public void setIndex(Index i)

let it know which index to use

Specified by:

setIndex in interface IndexConfigurable

Parameters:

i - Index object to use

getDocuments

public int[][] getDocuments(BitIndexPointer pointer)

Returns a 2D array containing the document ids, the term frequencies, the field scores the block frequencies and the block ids for the given documents.

Overrides:

getDocuments in class InvertedIndex

Parameters:

pointer - start byte and bit offset of the postings in the inverted file, together with number of postings to expect

Returns:

int[][] the five dimensional [5][] array containing the document ids, frequencies, field scores and block frequencies, while the last vector contains the block identifiers and it has a different length from the document identifiers.