com.exalead.search.query.prefix

Class SimilarDocumentPrefix

java.lang.Object

com.exalead.search.query.node.NodeVisitor

com.exalead.search.query.prefix.SimilarDocumentPrefix

All Implemented Interfaces:

PrefixHandler

public class SimilarDocumentPrefix
extends NodeVisitor
implements PrefixHandler

This handler accepts queries of the form similar:(keyword_id keyword_id ...) where keyword ids are strings from V62015x. It turns this query into keyword:keyword_id{s=s1} OR keyword:keyword_id{s=s2} ... where s1 and s2 are scores computed from their frequencies (the higher, the lower the score).

Nested Class Summary

Nested classes/interfaces inherited from interface com.exalead.search.query.prefix.PrefixHandler

PrefixHandler.ErrorBehaviour, PrefixHandler.NoHooks, PrefixHandler.Phase

Field Summary

Fields

Modifier and Type	Field and Description
protected QueryContext	context
protected long	cut
protected RelatedTermsDictionaryLookup	dictionary
protected java.lang.String	dictionaryName
protected java.lang.String	dictionaryPath
protected java.lang.String	keywordField
protected org.apache.log4j.Logger	log
protected long	minNumberOfKeywordPerDoc
protected int	minNumberOfMatchedKeywords
protected RelatedTermsDictResource	resource
protected long	scale
protected java.lang.String	virtualField

Constructor Summary

Constructors

Constructor and Description
SimilarDocumentPrefix(UQLConfig uqlConfig, java.lang.String virtualField, long minNumberOfMatchedKeywords, long minNumberOfKeywordPerDoc, double similarityThreshold, java.lang.String keywordField, java.lang.String dictionaryName, java.lang.String dictionaryPath)

Method Summary

Modifier and Type	Method and Description
Node	handlePrefix(PrefixHandler.Phase phase, PrefixNode node, NodeVisitor parentVisitor, QueryContext queryContext) Handle a given prefix node.
protected long	keywordScore(long freq, long maxFreq)
protected void	loadDictionary(java.lang.String path)
void	onDeinit() Called when this instance of the prefix handler is deinitialized.
void	onInit(PrefixHandlerContext context) Called when this instance of the prefix handler is initialized.
void	onQuery(QueryContext context) Called when a query is about to be processed.
void	setErrorBehaviour(PrefixHandler.ErrorBehaviour behaviour) Choose the error behaviour of the prefix handler.
protected java.lang.String	virtualFieldExpression(double upperBound)
Node	visit(UserQueryChunk node)

Methods inherited from class com.exalead.search.query.node.NodeVisitor

visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visitNary, visitUnary

Methods inherited from class java.lang.Object

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

Field Detail

dictionaryName

protected java.lang.String dictionaryName

scale

protected final long scale

See Also:

Constant Field Values

dictionary

protected RelatedTermsDictionaryLookup dictionary

resource

protected RelatedTermsDictResource resource

dictionaryPath

protected java.lang.String dictionaryPath

minNumberOfMatchedKeywords

protected int minNumberOfMatchedKeywords

minNumberOfKeywordPerDoc

protected long minNumberOfKeywordPerDoc

cut

protected long cut

virtualField

protected java.lang.String virtualField

keywordField

protected java.lang.String keywordField

context

protected QueryContext context

log

protected org.apache.log4j.Logger log

Constructor Detail

SimilarDocumentPrefix

public SimilarDocumentPrefix(UQLConfig uqlConfig,
                             java.lang.String virtualField,
                             long minNumberOfMatchedKeywords,
                             long minNumberOfKeywordPerDoc,
                             double similarityThreshold,
                             java.lang.String keywordField,
                             java.lang.String dictionaryName,
                             java.lang.String dictionaryPath)

Method Detail

handlePrefix

public Node handlePrefix(PrefixHandler.Phase phase,
                         PrefixNode node,
                         NodeVisitor parentVisitor,
                         QueryContext queryContext)
                  throws QueryProcessingException

Description copied from interface: PrefixHandler

Handle a given prefix node.

Specified by:

handlePrefix in interface PrefixHandler

Parameters:

phase - the "Phase" of the prefix handler, indicating how far in the pipeline we are.In the standard chain, 4 phases are defined: PRE_LINGUISTIC, PRE_TRANSFORM, PRE_MAP, POST_MAP

node - The prefix node to handle

parentVisitor - If your handler is not "terminal", ie, if it supports nesting, it should call this visitor to visit the prefix node's content, additionally to performing its work. Warning: this can be null, in that case, you must not delegate.
For example, a "URL" node handler might be terminal (ie, it will "eat" all its content), whereas a "soundlike" handler will not be. It will only set the correct expansion options and pass control to lower prefixes, to support things like: soundslike:(foo OR bar OR text:coin)

queryContext - access to overridable query-related parameters

Throws:

QueryProcessingException

loadDictionary

protected void loadDictionary(java.lang.String path)
                       throws ResourceNotFoundException,
                              ResourceAllocationFailedException

Throws:

ResourceNotFoundException

ResourceAllocationFailedException

visit

public Node visit(UserQueryChunk node)

Overrides:

visit in class NodeVisitor

setErrorBehaviour

public void setErrorBehaviour(PrefixHandler.ErrorBehaviour behaviour)

Description copied from interface: PrefixHandler

Choose the error behaviour of the prefix handler.

Specified by:

setErrorBehaviour in interface PrefixHandler

keywordScore

protected long keywordScore(long freq,
                            long maxFreq)

virtualFieldExpression

protected java.lang.String virtualFieldExpression(double upperBound)

onInit

public void onInit(PrefixHandlerContext context)

Description copied from interface: PrefixHandler

Called when this instance of the prefix handler is initialized.

Specified by:

onInit in interface PrefixHandler

onDeinit

public void onDeinit()

Description copied from interface: PrefixHandler

Called when this instance of the prefix handler is deinitialized. This instance will not be reused after this. Cleanup of instance resources should be done here rather than in a finalizer, as it offers a better control on the resource lifecycle.

Specified by:

onDeinit in interface PrefixHandler

onQuery

public void onQuery(QueryContext context)
             throws QueryProcessingException

Description copied from interface: PrefixHandler

Called when a query is about to be processed. handlePrefix() will then be called for each prefix matching. Note that onQuery might be called without handlePrefix being called if no prefix in the query matches this prefix handler.

Specified by:

onQuery in interface PrefixHandler

Throws:

QueryProcessingException