org.elasticsearch.search.suggest.term.TermSuggester Maven / Gradle / Ivy
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/*
* Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
* or more contributor license agreements. Licensed under the Elastic License
* 2.0 and the Server Side Public License, v 1; you may not use this file except
* in compliance with, at your election, the Elastic License 2.0 or the Server
* Side Public License, v 1.
*/
package org.elasticsearch.search.suggest.term;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.spell.DirectSpellChecker;
import org.apache.lucene.search.spell.SuggestWord;
import org.apache.lucene.util.BytesRef;
import org.apache.lucene.util.BytesRefBuilder;
import org.apache.lucene.util.CharsRefBuilder;
import org.elasticsearch.common.bytes.BytesArray;
import org.elasticsearch.common.text.Text;
import org.elasticsearch.search.suggest.Suggester;
import org.elasticsearch.search.suggest.SuggestionSearchContext.SuggestionContext;
import org.elasticsearch.search.suggest.phrase.DirectCandidateGenerator;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
public final class TermSuggester extends Suggester {
public static final TermSuggester INSTANCE = new TermSuggester();
private TermSuggester() {}
@Override
public TermSuggestion innerExecute(String name, TermSuggestionContext suggestion, IndexSearcher searcher, CharsRefBuilder spare)
throws IOException {
DirectSpellChecker directSpellChecker = suggestion.getDirectSpellCheckerSettings().createDirectSpellChecker();
final IndexReader indexReader = searcher.getIndexReader();
TermSuggestion response = new TermSuggestion(name, suggestion.getSize(), suggestion.getDirectSpellCheckerSettings().sort());
List tokens = queryTerms(suggestion, spare);
for (Token token : tokens) {
// TODO: Extend DirectSpellChecker in 4.1, to get the raw suggested words as BytesRef
SuggestWord[] suggestedWords = directSpellChecker.suggestSimilar(
token.term,
suggestion.getShardSize(),
indexReader,
suggestion.getDirectSpellCheckerSettings().suggestMode()
);
Text key = new Text(new BytesArray(token.term.bytes()));
TermSuggestion.Entry resultEntry = new TermSuggestion.Entry(key, token.startOffset, token.endOffset - token.startOffset);
for (SuggestWord suggestWord : suggestedWords) {
Text word = new Text(suggestWord.string);
resultEntry.addOption(new TermSuggestion.Entry.Option(word, suggestWord.freq, suggestWord.score));
}
response.addTerm(resultEntry);
}
return response;
}
private static List queryTerms(SuggestionContext suggestion, CharsRefBuilder spare) throws IOException {
final List result = new ArrayList<>();
final String field = suggestion.getField();
DirectCandidateGenerator.analyze(
suggestion.getAnalyzer(),
suggestion.getText(),
field,
new DirectCandidateGenerator.TokenConsumer() {
@Override
public void nextToken() {
Term term = new Term(field, BytesRef.deepCopyOf(fillBytesRef(new BytesRefBuilder())));
result.add(new Token(term, offsetAttr.startOffset(), offsetAttr.endOffset()));
}
},
spare
);
return result;
}
private static class Token {
public final Term term;
public final int startOffset;
public final int endOffset;
private Token(Term term, int startOffset, int endOffset) {
this.term = term;
this.startOffset = startOffset;
this.endOffset = endOffset;
}
}
@Override
protected TermSuggestion emptySuggestion(String name, TermSuggestionContext suggestion, CharsRefBuilder spare) throws IOException {
TermSuggestion termSuggestion = new TermSuggestion(name, suggestion.getSize(), suggestion.getDirectSpellCheckerSettings().sort());
List tokens = queryTerms(suggestion, spare);
for (Token token : tokens) {
Text key = new Text(new BytesArray(token.term.bytes()));
TermSuggestion.Entry resultEntry = new TermSuggestion.Entry(key, token.startOffset, token.endOffset - token.startOffset);
termSuggestion.addTerm(resultEntry);
}
return termSuggestion;
}
}