uk.ac.gla.terrier.querying.parser
Class PhraseQuery

java.lang.Object
  uk.ac.gla.terrier.querying.parser.Query
      uk.ac.gla.terrier.querying.parser.MultiTermQuery
          uk.ac.gla.terrier.querying.parser.PhraseQuery

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable

public class PhraseQuery
extends MultiTermQuery

Models a phrase query, which can have a proximity requirement.

Version:

$Revision: 1.18 $

Author:

Vassilis Plachouras, Craig Macdonald

See Also:

Serialized Form

Constructor Summary

PhraseQuery()
A default constructor that calls the constructor of the super class.

PhraseQuery(int proxDistance)
Constructs a phrase query and sets the proximity distance

Method Summary

java.lang.Object	clone() Deep copy this Query object
void	getTermsOf(java.lang.Class c, java.util.ArrayList alist, boolean req) Returns all the query terms, in subqueries that are instances of a given class
boolean	obtainControls(java.util.HashSet allowed, java.util.Hashtable controls) This object cannot contain any controls, so this method will always return false.
void	obtainQueryTerms(MatchingQueryTerms terms) Stores the query terms of the phrase query in the given matching query terms structure.
void	obtainQueryTerms(MatchingQueryTerms terms, boolean required) Stores the query terms of the phrase query in the given matching query terms structure.
void	setProximityDistance(int prox) Sets the allowed distance, in blocks, between the phrase terms.
java.lang.String	toString() Returns a string representation of the phrase query.

Methods inherited from class uk.ac.gla.terrier.querying.parser.MultiTermQuery

add, add, applyTermPipeline, getNumberOfTerms, obtainAllOf

Methods inherited from class uk.ac.gla.terrier.querying.parser.Query

setChild

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

PhraseQuery

public PhraseQuery()

A default constructor that calls the constructor of the super class.

PhraseQuery

public PhraseQuery(int proxDistance)

Constructs a phrase query and sets the proximity distance

Parameters:

proxDistance - int the distance, in number of blocks, that the phrase terms can appear in a document.

Method Detail

clone

public java.lang.Object clone()

Description copied from class: Query

Deep copy this Query object

Overrides:

clone in class MultiTermQuery

setProximityDistance

public void setProximityDistance(int prox)

Sets the allowed distance, in blocks, between the phrase terms.

Parameters:

prox - the allowed distance between the phrase terms.

toString

public java.lang.String toString()

Returns a string representation of the phrase query.

Overrides:

toString in class MultiTermQuery

Returns:

String the string representation of the phrase query.

obtainQueryTerms

public void obtainQueryTerms(MatchingQueryTerms terms)

Stores the query terms of the phrase query in the given matching query terms structure. The query terms are required to appear in the matched documents.

Overrides:

obtainQueryTerms in class MultiTermQuery

Parameters:

terms - MatchingQueryTerms the structure that stores the query terms for matching.

obtainQueryTerms

public void obtainQueryTerms(MatchingQueryTerms terms,
                             boolean required)

Stores the query terms of the phrase query in the given matching query terms structure. Whether the phrase is required to appear in the retrieved documents, depends on the value of the parameter required.

Overrides:

obtainQueryTerms in class MultiTermQuery

Parameters:

terms - MatchingQueryTerms the structure that stores the query terms for matching.

required - boolean indicates whether the phrase is required or not.

obtainControls

public boolean obtainControls(java.util.HashSet allowed,
                              java.util.Hashtable controls)

This object cannot contain any controls, so this method will always return false.

Overrides:

obtainControls in class MultiTermQuery

Parameters:

allowed - The HashSet of control names that are allowed to be set.

controls - The Hashtable into which child objects much add found controls

Returns:

false

getTermsOf

public void getTermsOf(java.lang.Class c,
                       java.util.ArrayList alist,
                       boolean req)

Returns all the query terms, in subqueries that are instances of a given class

Overrides:

getTermsOf in class MultiTermQuery

Parameters:

c - Class a class of queries.

alist - ArrayList the list of query terms.

req - boolean indicates whether the subqueries are required or not.