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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.search.query.rewrite.rewriters;
import java.io.*;
import java.util.*;
import java.util.logging.Logger;
import com.yahoo.component.annotation.Inject;
import com.yahoo.component.chain.dependencies.After;
import com.yahoo.component.chain.dependencies.Provides;
import com.yahoo.search.query.rewrite.*;
import com.yahoo.search.*;
import com.yahoo.component.ComponentId;
import com.yahoo.filedistribution.fileacquirer.FileAcquirer;
import com.yahoo.search.query.rewrite.RewritesConfig;
/**
* This rewriter would retrieve spell corrected query from QLAS and
* add it to the original query tree as equiv<br>
* - Features:<br>
* RewritesAsEquiv flag: add rewrites to original query as equiv
*
* @author Karen Sze Wing Lee
*/
@After("QLAS")
@Provides("MisspellRewriter")
public class MisspellRewriter extends QueryRewriteSearcher {
// Flag for skipping this rewriter if the query has been rewritten
private final boolean SKIP_REWRITER_IF_REWRITTEN = false;
// Name of the rewriter
public static final String REWRITER_NAME = "MisspellRewriter";
private Logger logger = Logger.getLogger(MisspellRewriter.class.getName());
/**
* Constructor for MisspellRewriter
*/
@Inject
public MisspellRewriter(ComponentId id) {
super(id);
}
/**
* Constructor for MisspellRewriter unit test
*/
public MisspellRewriter() {
super();
}
/**
* Instance creation time config loading besides FSA.
* Empty for this rewriter
*/
public boolean configure(FileAcquirer fileAcquirer,
RewritesConfig config,
HashMap<String, File> fileList) {
return true;
}
/**
* Main logic of rewriter<br>
* - Retrieve spell corrected query from QLAS<br>
* - Add spell corrected query as equiv
*/
public HashMap<String, Object> rewrite(Query query,
String dictKey) throws RuntimeException {
Boolean rewritten = false;
HashMap<String, Object> result = new HashMap<>();
result.put(RewriterConstants.REWRITTEN, rewritten);
result.put(RewriterConstants.DICT_KEY, dictKey);
RewriterUtils.log(logger, query,
"In MisspellRewriter");
// Retrieve flags for enabling the features
String qssRw = getQPConfig(query, RewriterConstants.QSS_RW);
String qssSugg = getQPConfig(query, RewriterConstants.QSS_SUGG);
boolean isQSSRw = false;
boolean isQSSSugg = false;
if(qssRw!=null) {
isQSSRw = qssRw.equalsIgnoreCase("true");
}
if(qssSugg!=null) {
isQSSSugg = qssSugg.equalsIgnoreCase("true");
}
// Rewrite is not enabled
if(!isQSSRw && !isQSSSugg) {
return result;
}
// Retrieve spell corrected query from QLAS
String rewrites = RewriterUtils.getSpellCorrected(query, isQSSRw, isQSSSugg);
// No rewrites
if(rewrites==null) {
RewriterUtils.log(logger, query, "No rewrite is retrieved");
return result;
} else {
RewriterUtils.log(logger, query, "Retrieved spell corrected query: " +
rewrites);
}
// Adding rewrite to the query tree
query = RewriterFeatures.addRewritesAsEquiv(query, dictKey, rewrites, false, 0);
rewritten = true;
RewriterUtils.log(logger, query, "MisspellRewriter final query: " +
query.toDetailString());
result.put(RewriterConstants.REWRITTEN, rewritten);
result.put(RewriterConstants.DICT_KEY, rewrites);
return result;
}
/**
* Get the flag which specifies whether this rewriter
* should be skipped if the query has been rewritten
*
* @return true if rewriter should be skipped, false
* otherwise
*/
public boolean getSkipRewriterIfRewritten() {
return SKIP_REWRITER_IF_REWRITTEN;
}
/**
* Get the name of the rewriter
*
* @return Name of the rewriter
*/
public String getRewriterName() {
return REWRITER_NAME;
}
/**
* Get default FSA dictionary names
*
* @return Pair of FSA dictionary name and filename
*/
public HashMap<String, String> getDefaultFSAs() {
return null;
}
}
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