org.terrier.structures
Class InvertedIndex

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

All Implemented Interfaces:

java.io.Closeable, PostingIndex<BitIndexPointer>

Direct Known Subclasses:

BlockInvertedIndex

public class InvertedIndex
extends BitPostingIndex

This class implements the inverted index for performing retrieval, with field information optionally.

Author:

Douglas Johnson, Vassilis Plachouras, Craig Macdonald

Field Summary

protected DocumentIndex	doi
static double	FIELD_LOAD_FACTOR This is used during retrieval for a rough guess sizing of the temporaryTerms arraylist in getDocuments() - retrieval with Fields.
protected static org.apache.log4j.Logger	logger The logger used for the Lexicon
static double	NORMAL_LOAD_FACTOR This is used during retrieval for a rough guess sizing of the temporaryTerms arraylist in getDocuments().

Fields inherited from class org.terrier.structures.BitPostingIndex

fieldCount, file, index, postingConstructor, postingImplementation

Constructor Summary

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

InvertedIndex(Index index, java.lang.String structureName, DocumentIndex _doi)
Construct an instance of the class with

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

Method Summary

BitInSeekable[]	getBitFiles() Get the BitFiles
int[][]	getDocuments(BitIndexPointer pointer) Get the documents for for the posting list using the pointer given
int[][]	getDocuments(LexiconEntry le) Get the documents for the specified term (lexicon entry for the term)
IterablePosting	getPostings(BitIndexPointer pointer) Get the posting given a pointer
void	print() Print out the Inverted Index

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

logger

protected static final org.apache.log4j.Logger logger

The logger used for the Lexicon

NORMAL_LOAD_FACTOR

public static final double NORMAL_LOAD_FACTOR

This is used during retrieval for a rough guess sizing of the temporaryTerms arraylist in getDocuments(). The higher this value, the less chance that the arraylist will have to be grown (growing is expensive), however more memory may be used unnecessarily.

See Also:

Constant Field Values

FIELD_LOAD_FACTOR

public static final double FIELD_LOAD_FACTOR

This is used during retrieval for a rough guess sizing of the temporaryTerms arraylist in getDocuments() - retrieval with Fields. The higher this value, the less chance that the arraylist will have to be grown (growing is expensive), however more memory may be used unnecessarily.

See Also:

Constant Field Values

doi

protected DocumentIndex doi

Constructor Detail

InvertedIndex

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

Construct an instance of the class with

Parameters:

index -

structureName -

Throws:

java.io.IOException

InvertedIndex

public InvertedIndex(Index index,
                     java.lang.String structureName,
                     DocumentIndex _doi)
              throws java.io.IOException

Construct an instance of the class with

Parameters:

index -

structureName -

_doi -

Throws:

java.io.IOException

InvertedIndex

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

Construct an instance of the class with

Parameters:

index -

structureName -

_doi -

postingClass -

Throws:

java.io.IOException

Method Detail

getBitFiles

public BitInSeekable[] getBitFiles()

Get the BitFiles

print

public void print()

Print out the Inverted Index

getPostings

public IterablePosting getPostings(BitIndexPointer pointer)
                            throws java.io.IOException

Description copied from class: BitPostingIndex

Get the posting given a pointer

Specified by:

getPostings in interface PostingIndex<BitIndexPointer>

Overrides:

getPostings in class BitPostingIndex

Throws:

java.io.IOException

getDocuments

public int[][] getDocuments(LexiconEntry le)

Get the documents for the specified term (lexicon entry for the term)

getDocuments

public int[][] getDocuments(BitIndexPointer pointer)

Get the documents for for the posting list using the pointer given