Package org.terrier.matching.matchops

Class MultiTermOp

java.lang.Object

org.terrier.matching.matchops.Operator

org.terrier.matching.matchops.MultiTermOp

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable

Direct Known Subclasses:

ANDQueryOp, SynonymOp

public abstract class MultiTermOp
extends Operator

this is an abstract operator, which implements common functionalities for operators that consist of multiple terms.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected static org.slf4j.Logger	logger

Fields inherited from class org.terrier.matching.matchops.Operator

IGNORE_LOW_IDF_TERMS

Constructor Summary

Constructors

Constructor	Description
MultiTermOp(java.lang.String[] ts, boolean allRequired)
MultiTermOp(Operator[] _ts, boolean _allRequired)

Method Summary

Modifier and Type	Method	Description
static EntryStatistics	addStatistics(EntryStatistics[] entryStats)	merges several EntryStatistics for a single effective term simply by adding
MultiTermOp	clone()
protected abstract IterablePosting	createFinalPostingIterator(java.util.List<IterablePosting> postings, java.util.List<EntryStatistics> pointers)
Operator[]	getConstituents()
MatchingEntry	getMatcher(MatchingQueryTerms.QueryTermProperties qtp, Index index, Lexicon<java.lang.String> lexicon, PostingIndex<Pointer> invertedIndex, CollectionStatistics collectionStatistics)	get an entry for matching for this query op.
org.apache.commons.lang3.tuple.Pair<EntryStatistics,IterablePosting>	getPostingIterator(Index index)	get posting iterator for this query op.
protected EntryStatistics	mergeStatistics(EntryStatistics[] entryStats, CollectionStatistics collStats)

Methods inherited from class org.terrier.matching.matchops.Operator

equals, hashCode, parse, toString

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

logger

protected static final org.slf4j.Logger logger

Constructor Detail

MultiTermOp

public MultiTermOp(java.lang.String[] ts,
                   boolean allRequired)

MultiTermOp

public MultiTermOp(Operator[] _ts,
                   boolean _allRequired)

Method Detail

getConstituents

public Operator[] getConstituents()

addStatistics

public static EntryStatistics addStatistics(EntryStatistics[] entryStats)

merges several EntryStatistics for a single effective term simply by adding

mergeStatistics

protected EntryStatistics mergeStatistics(EntryStatistics[] entryStats,
                                          CollectionStatistics collStats)

createFinalPostingIterator

protected abstract IterablePosting createFinalPostingIterator(java.util.List<IterablePosting> postings,
                                                              java.util.List<EntryStatistics> pointers)
                                                       throws java.io.IOException

Throws:

java.io.IOException

getPostingIterator

public org.apache.commons.lang3.tuple.Pair<EntryStatistics,IterablePosting> getPostingIterator(Index index)
                                                                                              throws java.io.IOException

Description copied from class: Operator

get posting iterator for this query op.

Specified by:

getPostingIterator in class Operator

Returns:

Pair, but Pair.of(null,null) if term not found

Throws:

java.io.IOException

getMatcher

public MatchingEntry getMatcher(MatchingQueryTerms.QueryTermProperties qtp,
                                Index index,
                                Lexicon<java.lang.String> lexicon,
                                PostingIndex<Pointer> invertedIndex,
                                CollectionStatistics collectionStatistics)
                         throws java.io.IOException

Description copied from class: Operator

get an entry for matching for this query op. calls getPostingIterator() internally

Specified by:

getMatcher in class Operator

Throws:

java.io.IOException

clone

public MultiTermOp clone()

Overrides:

clone in class Operator