Module org.apache.lucene.suggest

Package org.apache.lucene.search.suggest.document

Class ContextQuery

java.lang.Object

org.apache.lucene.search.Query

org.apache.lucene.search.suggest.document.CompletionQuery

org.apache.lucene.search.suggest.document.ContextQuery

All Implemented Interfaces:

Accountable

public class ContextQuery
extends CompletionQuery
implements Accountable

A CompletionQuery that matches documents specified by a wrapped CompletionQuery supporting boosting and/or filtering by specified contexts.

Use this query against ContextSuggestField

Example of using a CompletionQuery with boosted contexts:

  CompletionQuery completionQuery = ...;
  ContextQuery query = new ContextQuery(completionQuery);
  query.addContext("context1", 2);
  query.addContext("context2", 1);
 

NOTE:

• This query can be constructed with PrefixCompletionQuery, RegexCompletionQuery or FuzzyCompletionQuery query.
• To suggest across all contexts, use addAllContexts(). When no context is added, the default behaviour is to suggest across all contexts.
• To apply the same boost to multiple contexts sharing the same prefix, Use addContext(CharSequence, float, boolean) with the common context prefix, boost and set exact to false.
• Using this query against a SuggestField (not context enabled), would yield results ignoring any context filtering/boosting

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	ContextQuery.ContextCompletionWeight
private static class	ContextQuery.ContextMetaData	Holder for context value meta data

Field Summary

Fields

Modifier and Type	Field	Description
private static final long	BASE_RAM_BYTES
private Map<IntsRef,ContextQuery.ContextMetaData>	contexts
protected CompletionQuery	innerQuery	Inner completion query
private boolean	matchAllContexts
private long	ramBytesUsed
private IntsRefBuilder	scratch

Fields inherited from interface org.apache.lucene.util.Accountable

NULL_ACCOUNTABLE

Constructor Summary

Constructors

Constructor	Description
ContextQuery(CompletionQuery query)	Constructs a context completion query that matches documents specified by query.

Method Summary

Modifier and Type	Method	Description
void	addAllContexts()	Add all contexts with a boost of 1f
void	addContext(CharSequence context)	Adds an exact context with default boost of 1
void	addContext(CharSequence context, float boost)	Adds an exact context with boost
void	addContext(CharSequence context, float boost, boolean exact)	Adds a context with boost, set exact to false if the context is a prefix of any indexed contexts
Weight	createWeight(IndexSearcher searcher, ScoreMode scoreMode, float boost)	Expert: Constructs an appropriate Weight implementation for this query.
boolean	equals(Object o)	Override and implement query instance equivalence properly in a subclass.
int	hashCode()	Override and implement query hash code properly in a subclass.
long	ramBytesUsed()	Return the memory usage of this object in bytes.
private static void	sortDescending(int[] array)	Sorts and reverses the array.
private static Automaton	toContextAutomaton(Map<IntsRef,ContextQuery.ContextMetaData> contexts, boolean matchAllContexts)
String	toString(String field)	Prints a query to a string, with field assumed to be the default field and omitted.
private void	updateRamBytesUsed()
void	visit(QueryVisitor visitor)	Recurse through the query tree, visiting any child queries.

Methods inherited from class org.apache.lucene.search.suggest.document.CompletionQuery

getField, getFilter, getTerm, rewrite

Methods inherited from class org.apache.lucene.search.Query

classHash, rewrite, sameClassAs, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.lucene.util.Accountable

getChildResources

Field Details

BASE_RAM_BYTES

private static final long BASE_RAM_BYTES

scratch

private IntsRefBuilder scratch

contexts

private Map<IntsRef,ContextQuery.ContextMetaData> contexts

matchAllContexts

private boolean matchAllContexts

innerQuery

protected CompletionQuery innerQuery

Inner completion query

ramBytesUsed

private long ramBytesUsed

Constructor Details

ContextQuery

public ContextQuery(CompletionQuery query)

Constructs a context completion query that matches documents specified by query.

Use addContext(CharSequence, float, boolean) to add context(s) with boost

Method Details

updateRamBytesUsed

private void updateRamBytesUsed()

addContext

public void addContext(CharSequence context)

Adds an exact context with default boost of 1

addContext

public void addContext(CharSequence context,
 float boost)

Adds an exact context with boost

addContext

public void addContext(CharSequence context,
 float boost,
 boolean exact)

Adds a context with boost, set exact to false if the context is a prefix of any indexed contexts

addAllContexts

public void addAllContexts()

Add all contexts with a boost of 1f

toString

public String toString(String field)

Description copied from class: Query

Prints a query to a string, with field assumed to be the default field and omitted.

Overrides:

toString in class CompletionQuery

createWeight

public Weight createWeight(IndexSearcher searcher,
 ScoreMode scoreMode,
 float boost)
                    throws IOException

Description copied from class: Query

Expert: Constructs an appropriate Weight implementation for this query.

Only implemented by primitive queries, which re-write to themselves.

Overrides:

createWeight in class Query

Parameters:

scoreMode - How the produced scorers will be consumed.

boost - The boost that is propagated by the parent queries.

Throws:

IOException

sortDescending

private static void sortDescending(int[] array)

Sorts and reverses the array.

toContextAutomaton

private static Automaton toContextAutomaton(Map<IntsRef,ContextQuery.ContextMetaData> contexts,
 boolean matchAllContexts)

equals

public boolean equals(Object o)

Description copied from class: Query

Override and implement query instance equivalence properly in a subclass. This is required so that QueryCache works properly.

Typically a query will be equal to another only if it's an instance of the same class and its document-filtering properties are identical to those of the other instance. Utility methods are provided for certain repetitive code.

Specified by:

equals in class Query

See Also:

• Query.sameClassAs(Object)
• Query.classHash()

hashCode

public int hashCode()

Description copied from class: Query

Override and implement query hash code properly in a subclass. This is required so that QueryCache works properly.

Specified by:

hashCode in class Query

See Also:

• Query.equals(Object)

visit

public void visit(QueryVisitor visitor)

Description copied from class: Query

Recurse through the query tree, visiting any child queries.

Specified by:

visit in class Query

Parameters:

visitor - a QueryVisitor to be called by each query in the tree

ramBytesUsed

public long ramBytesUsed()

Description copied from interface: Accountable

Return the memory usage of this object in bytes. Negative values are illegal.

Specified by:

ramBytesUsed in interface Accountable