org.terrier.querying.parser

Class MultiTermQuery

java.lang.Object

org.terrier.querying.parser.Query

org.terrier.querying.parser.MultiTermQuery

All Implemented Interfaces:

Serializable, Cloneable

Direct Known Subclasses:

DisjunctiveQuery, ExplicitMultiTermQuery, PhraseQuery, SegmentQuery

public class MultiTermQuery
extends Query

Represents a query consisting of more than one terms or other sub-queries, qualified with field, requirement or phrase operators.

Author:

Vassilis Plachouras, Craig Macdonald

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.terrier.querying.parser.Query

Query.ForEachQueryNode

Field Summary

Fields

Modifier and Type	Field and Description
protected String	prefix
protected String	suffix
protected ArrayList<Query>	v A list for holding the sub-queries.

Fields inherited from class org.terrier.querying.parser.Query

child, tmpSTQ

Constructor Summary

Constructors

Constructor and Description
MultiTermQuery() A default constructor.

Method Summary

Methods

Modifier and Type	Method and Description
void	add(Query query) Adds a subquery to this query.
void	add(String term) Adds a single query term to the query.
void	apply(Query.ForEachQueryNode processor) Apply the specified processor to this node.
boolean	applyTermPipeline(TermPipelineAccessor tpa) Applies the given term pipeline to the query terms and sub-queries that construct this query.
Object	clone() Deep copy this Query object
int	getNumberOfTerms() Returns the number of terms, or subqueries.
protected void	getTerms(List<Query> alist) Adds all the subqueries and single-term queries to a given array list.
void	getTermsOf(Class<? extends Query> c, List<Query> alist, boolean req) Returns all the query terms, in subqueries that are instances of a given class
void	obtainAllOf(Class<? extends Query> c, List<Query> a) Returns all the queries of the specified class
boolean	obtainControls(Set<String> allowed, Map<String,String> controls) Checks all child objects to see if they are FieldQuery objects, they are each called to see if the are controls.
void	obtainQueryTerms(MatchingQueryTerms terms) Prepares the query for matching by transforming the query objects to a set of query terms.
void	obtainQueryTerms(MatchingQueryTerms terms, boolean required) Prepares the query for matching by transforming the query objects to a set of query terms.
String	parseTree() Returns the parse tree for the query as a string
void	replace(Query childNode, Query replacement) Replace query node
String	toString() Returns a string representation of the query.

Methods inherited from class org.terrier.querying.parser.Query

setChild

Methods inherited from class java.lang.Object

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

Field Detail

prefix

protected String prefix

suffix

protected String suffix

v

protected ArrayList<Query> v

A list for holding the sub-queries. A LinkedList is ideal as we have no need to access numbered sub-query elements of the query - only be able to iterate throught them.

Constructor Detail

MultiTermQuery

public MultiTermQuery()

A default constructor.

Method Detail

getNumberOfTerms

public int getNumberOfTerms()

Returns the number of terms, or subqueries.

Returns:

int the number of terms, or subqueries of this query.

clone

public Object clone()

Deep copy this Query object

Overrides:

clone in class Query

add

public void add(String term)

Adds a single query term to the query.

Parameters:

term - String the query term.

add

public void add(Query query)

Adds a subquery to this query.

Parameters:

query - Query a subquery.

toString

public String toString()

Returns a string representation of the query.

Specified by:

toString in class Query

Returns:

String the string of this query.

applyTermPipeline

public boolean applyTermPipeline(TermPipelineAccessor tpa)

Applies the given term pipeline to the query terms and sub-queries that construct this query.

Overrides:

applyTermPipeline in class Query

Parameters:

tpa - TermPipelineAccessor the object that gives access to a term pipeline.

Returns:

boolean true if the query is not empty, otherwise returns false.

obtainQueryTerms

public void obtainQueryTerms(MatchingQueryTerms terms)

Prepares the query for matching by transforming the query objects to a set of query terms.

Overrides:

obtainQueryTerms in class Query

Parameters:

terms - MatchingQueryTerms the object which holds the query terms and their modifiers.

obtainQueryTerms

public void obtainQueryTerms(MatchingQueryTerms terms,
                    boolean required)

Prepares the query for matching by transforming the query objects to a set of query terms.

Overrides:

obtainQueryTerms in class Query

Parameters:

terms - MatchingQueryTerms the object which holds the query terms and their modifiers.

required - boolean indicates whether the field query is required or not.

getTerms

protected void getTerms(List<Query> alist)

Adds all the subqueries and single-term queries to a given array list.

Overrides:

getTerms in class Query

Parameters:

alist - ArrayList the array list in which all the query terms and sub-queries are stored.

obtainControls

public boolean obtainControls(Set<String> allowed,
                     Map<String,String> controls)

Checks all child objects to see if they are FieldQuery objects, they are each called to see if the are controls. Child objects which return true are removed from the tree. If all child objects return true then this object is also considered dead, and should be removed.

Overrides:

obtainControls in class Query

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:

true if this object should be considered dead (no longer part of the query), false otherwise.

getTermsOf

public void getTermsOf(Class<? extends Query> c,
              List<Query> alist,
              boolean req)

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

Specified by:

getTermsOf in class Query

Parameters:

c - Class a class of queries.

alist - ArrayList the list of query terms.

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

replace

public void replace(Query childNode,
           Query replacement)

Replace query node

Parameters:

childNode -

replacement -

obtainAllOf

public void obtainAllOf(Class<? extends Query> c,
               List<Query> a)

Description copied from class: Query

Returns all the queries of the specified class

Overrides:

obtainAllOf in class Query

apply

public void apply(Query.ForEachQueryNode processor)

Apply the specified processor to this node. If the processor allows, move to any children nodes.

Overrides:

apply in class Query

Parameters:

processor -

parseTree

public String parseTree()

Description copied from class: Query

Returns the parse tree for the query as a string

Specified by:

parseTree in class Query