org.terrier.matching.matchops

Class PhraseOp

java.lang.Object

org.terrier.matching.matchops.Operator

org.terrier.matching.matchops.MultiTermOp

org.terrier.matching.matchops.ANDQueryOp

org.terrier.matching.matchops.PhraseOp

All Implemented Interfaces:

Serializable, Cloneable

public class PhraseOp
extends ANDQueryOp

This combines multiple operators into a single op, where they occur adjacently. It is logically equivalent to Indri's #1() operator.

Since:

5.0

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static String	STRING_PREFIX

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

logger

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

IGNORE_LOW_IDF_TERMS

Constructor Summary

Constructors

Constructor and Description
PhraseOp(Operator[] ts)
PhraseOp(String[] ts)

Method Summary

Modifier and Type	Method and Description
protected IterablePosting	createFinalPostingIterator(List<IterablePosting> postings, List<EntryStatistics> pointers)
protected EntryStatistics	mergeStatistics(EntryStatistics[] entryStats, CollectionStatistics collStats) Adjust the statistics for this operator: 1.
String	toString()

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

addStatistics, clone, getConstituents, getMatcher, getPostingIterator

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

equals, hashCode, parse

Methods inherited from class java.lang.Object

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

Field Detail

STRING_PREFIX

public static final String STRING_PREFIX

See Also:

Constant Field Values

Constructor Detail

PhraseOp

public PhraseOp(Operator[] ts)

PhraseOp

public PhraseOp(String[] ts)

Method Detail

toString

public String toString()

Overrides:

toString in class ANDQueryOp

mergeStatistics

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

Description copied from class: ANDQueryOp

Adjust the statistics for this operator: 1. The number of occurrences is the minimum of the constituent frequencies (handled by super). 2. The in-document maxTF is the minimum of the constituent maxTFs

Overrides:

mergeStatistics in class ANDQueryOp

createFinalPostingIterator

protected IterablePosting createFinalPostingIterator(List<IterablePosting> postings,
                                                     List<EntryStatistics> pointers)
                                              throws IOException

Overrides:

createFinalPostingIterator in class ANDQueryOp

Throws:

IOException