org.cdlib.xtf.textEngine

Class StdTermRewriter

Object

QueryRewriter

XtfQueryRewriter

StdTermRewriter

public class StdTermRewriter
extends XtfQueryRewriter

Rewrites a Lucene query to perform standard tokenization actions on each term, such as converting them to lowercase, removing apostrophes, etc.

Author:

Martin Haye

Nested Class Summary

Nested classes/interfaces inherited from class QueryRewriter

QueryRewriter.SpanClauseJoiner

Field Summary

Fields

Modifier and Type	Field and Description
private StdTermFilter	filter
private Set	tokenizedFields

Constructor Summary

Constructors

Constructor and Description
StdTermRewriter(Set tokFields) Construct a term rewriter that will operate on the given tokenized fields.

Method Summary

Modifier and Type	Method and Description
private String	mapTerm(Term t) Map the given term and return the mapped result.
protected Query	rewrite(SpanTermQuery q) Rewrite a span term query.
protected Query	rewrite(SpanWildcardQuery q) Rewrite a wildcard term query.
protected Query	rewrite(TermQuery q) Rewrite a term query.

Methods inherited from class XtfQueryRewriter

rewrite, rewrite, rewrite, rewrite, rewriteQuery

Methods inherited from class QueryRewriter

combineBoost, copyBoost, copyBoost, forceRewrite, rewrite, rewrite, rewrite, rewrite, rewrite, rewrite, rewrite, rewrite, rewrite, rewriteClauses

Methods inherited from class Object

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

Field Detail

tokenizedFields

private Set tokenizedFields

filter

private StdTermFilter filter

Constructor Detail

StdTermRewriter

public StdTermRewriter(Set tokFields)

Construct a term rewriter that will operate on the given tokenized fields.

Method Detail

rewrite

protected Query rewrite(TermQuery q)

Rewrite a term query. This is only called for artificial queries introduced by XTF system itself, and therefore we don't map here.

Overrides:

rewrite in class QueryRewriter

Parameters:

q - The query to rewrite

Returns:

Rewritten version, or 'q' unchanged if no changed needed.

rewrite

protected Query rewrite(SpanTermQuery q)

Rewrite a span term query.

Overrides:

rewrite in class QueryRewriter

Parameters:

q - The query to rewrite

Returns:

Rewritten version, or 'q' unchanged if no changed needed.

rewrite

protected Query rewrite(SpanWildcardQuery q)

Rewrite a wildcard term query.

Overrides:

rewrite in class QueryRewriter

Parameters:

q - The query to rewrite

Returns:

Rewritten version, or 'q' unchanged if no changed needed.

mapTerm

private String mapTerm(Term t)

Map the given term and return the mapped result.

Parameters:

t - term to map

Returns:

different term, or null if not different. Also null if the field isn't tokenized.