com.exalead.search.query.linguistic

Class LinguisticExpander

java.lang.Object

com.exalead.search.query.node.NodeVisitor

com.exalead.search.query.linguistic.LinguisticExpander

public class LinguisticExpander
extends NodeVisitor

Perform the tokenization of UserQueryChunks, and linguistic expansions using a set of MOT processors and their associated post-processors.
This class is not thread-safe, an instance per thread is required.
You do not instantiate this class, but acquire thread-specific instances through the LinguisticExpanderResource.

Linguistic expansion is done in four steps:

• Apply a MOT pipe to the UserQueryChunk.
  The pipeline contains all the semantic processor defined in the LinguisticExpanderResource.
• Prepare to request the Dictionary on behalf of all the post-processors defined in the LinguisticExpanderResource. The post-processors that need information from the Dictionary must prepare the queries they want to send.
• Call the Dictionary for expansion, with all the queries gathered.
• Call process() on all post-processors. The post-processors that required Dictionary data now have their answers ready.

When a node is received, the processors defined by node.options.linguisticExpansions are applied together with their options.

TODO: Multiple Dictionaries support

Field Summary

Fields

Modifier and Type	Field and Description
protected static org.apache.log4j.Logger	logger

Method Summary

Modifier and Type	Method and Description
protected com.exalead.dictionary.messages.MultiQuery	buildGDictQuery()
protected void	distributeGDictAnswers(com.exalead.dictionary.messages.MultiAnswer ma)
protected void	gatherGDict(RootNode node)
protected void	performMOTExpansion(RootNode node)
protected void	performReplacements(RootNode node)
void	releaseSuperfluous()
void	setParameters(QueryExpansionConfig config)
Node	visit(RootNode 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

logger

protected static final org.apache.log4j.Logger logger

Method Detail

setParameters

public void setParameters(QueryExpansionConfig config)

visit

public Node visit(RootNode node)
           throws QueryProcessingException

Overrides:

visit in class NodeVisitor

Throws:

QueryProcessingException

distributeGDictAnswers

protected void distributeGDictAnswers(com.exalead.dictionary.messages.MultiAnswer ma)

buildGDictQuery

protected com.exalead.dictionary.messages.MultiQuery buildGDictQuery()

performMOTExpansion

protected void performMOTExpansion(RootNode node)
                            throws QueryProcessingException

Throws:

QueryProcessingException

performReplacements

protected void performReplacements(RootNode node)
                            throws QueryProcessingException

Throws:

QueryProcessingException

gatherGDict

protected void gatherGDict(RootNode node)
                    throws QueryProcessingException

Throws:

QueryProcessingException

releaseSuperfluous

public void releaseSuperfluous()