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/*
* Licensed to ElasticSearch and Shay Banon under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. ElasticSearch licenses this
* file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.elasticsearch.search.suggest.phrase;
import java.io.IOException;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.util.BytesRef;
import org.elasticsearch.ElasticSearchIllegalArgumentException;
import org.elasticsearch.common.xcontent.XContentParser;
import org.elasticsearch.common.xcontent.XContentParser.Token;
import org.elasticsearch.index.analysis.ShingleTokenFilterFactory;
import org.elasticsearch.index.mapper.MapperService;
import org.elasticsearch.search.suggest.SuggestContextParser;
import org.elasticsearch.search.suggest.SuggestUtils;
import org.elasticsearch.search.suggest.SuggestionSearchContext;
import org.elasticsearch.search.suggest.phrase.PhraseSuggestionContext.DirectCandidateGenerator;
public final class PhraseSuggestParser implements SuggestContextParser {
private final PhraseSuggester suggester = new PhraseSuggester();
public SuggestionSearchContext.SuggestionContext parse(XContentParser parser, MapperService mapperService) throws IOException {
PhraseSuggestionContext suggestion = new PhraseSuggestionContext(suggester);
XContentParser.Token token;
String fieldName = null;
boolean gramSizeSet = false;
while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
if (token == XContentParser.Token.FIELD_NAME) {
fieldName = parser.currentName();
} else if (token.isValue()) {
if (!SuggestUtils.parseSuggestContext(parser, mapperService, fieldName, suggestion)) {
if ("real_word_error_likelihood".equals(fieldName) || "realWorldErrorLikelihood".equals(fieldName)) {
suggestion.setRealWordErrorLikelihood(parser.floatValue());
if (suggestion.realworldErrorLikelyhood() <= 0.0) {
throw new ElasticSearchIllegalArgumentException("real_word_error_likelihood must be > 0.0");
}
} else if ("confidence".equals(fieldName)) {
suggestion.setConfidence(parser.floatValue());
if (suggestion.confidence() < 0.0) {
throw new ElasticSearchIllegalArgumentException("confidence must be >= 0.0");
}
} else if ("separator".equals(fieldName)) {
suggestion.setSeparator(new BytesRef(parser.text()));
} else if ("max_errors".equals(fieldName) || "maxErrors".equals(fieldName)) {
suggestion.setMaxErrors(parser.floatValue());
if (suggestion.maxErrors() <= 0.0) {
throw new ElasticSearchIllegalArgumentException("max_error must be > 0.0");
}
} else if ("gram_size".equals(fieldName) || "gramSize".equals(fieldName)) {
suggestion.setGramSize(parser.intValue());
if (suggestion.gramSize() < 1) {
throw new ElasticSearchIllegalArgumentException("gram_size must be >= 1");
}
gramSizeSet = true;
} else if ("force_unigrams".equals(fieldName) || "forceUnigrams".equals(fieldName)) {
suggestion.setRequireUnigram(parser.booleanValue());
} else if ("token_limit".equals(fieldName) || "tokenLimit".equals(fieldName)) {
int tokenLimit = parser.intValue();
if (tokenLimit <= 0) {
throw new ElasticSearchIllegalArgumentException("token_limit must be >= 1");
}
suggestion.setTokenLimit(tokenLimit);
} else {
throw new ElasticSearchIllegalArgumentException("suggester[phrase] doesn't support field [" + fieldName + "]");
}
}
} else if (token == Token.START_ARRAY) {
if ("direct_generator".equals(fieldName) || "directGenerator".equals(fieldName)) {
// for now we only have a single type of generators
while ((token = parser.nextToken()) == Token.START_OBJECT) {
PhraseSuggestionContext.DirectCandidateGenerator generator = new PhraseSuggestionContext.DirectCandidateGenerator();
while ((token = parser.nextToken()) != Token.END_OBJECT) {
if (token == XContentParser.Token.FIELD_NAME) {
fieldName = parser.currentName();
}
if (token.isValue()) {
parseCandidateGenerator(parser, mapperService, fieldName, generator);
}
}
verifyGenerator(generator);
suggestion.addGenerator(generator);
}
} else {
throw new ElasticSearchIllegalArgumentException("suggester[phrase] doesn't support array field [" + fieldName + "]");
}
} else if (token == Token.START_OBJECT && "smoothing".equals(fieldName)) {
parseSmoothingModel(parser, suggestion, fieldName);
} else {
throw new ElasticSearchIllegalArgumentException("suggester[phrase] doesn't support field [" + fieldName + "]");
}
}
if (suggestion.getField() == null) {
throw new ElasticSearchIllegalArgumentException("The required field option is missing");
}
if (suggestion.model() == null) {
suggestion.setModel(StupidBackoffScorer.FACTORY);
}
if (!gramSizeSet || suggestion.generators().isEmpty()) {
final ShingleTokenFilterFactory.Factory shingleFilterFactory = SuggestUtils.getShingleFilterFactory(suggestion.getAnalyzer() == null ? mapperService.fieldSearchAnalyzer(suggestion.getField()) : suggestion.getAnalyzer()); ;
if (!gramSizeSet) {
// try to detect the shingle size
if (shingleFilterFactory != null) {
suggestion.setGramSize(shingleFilterFactory.getMaxShingleSize());
if (suggestion.getAnalyzer() == null && shingleFilterFactory.getMinShingleSize() > 1 && !shingleFilterFactory.getOutputUnigrams()) {
throw new ElasticSearchIllegalArgumentException("The default analyzer for field: [" + suggestion.getField() + "] doesn't emit unigrams. If this is intentional try to set the analyzer explicitly");
}
}
}
if (suggestion.generators().isEmpty()) {
if (shingleFilterFactory != null && shingleFilterFactory.getMinShingleSize() > 1 && !shingleFilterFactory.getOutputUnigrams() && suggestion.getRequireUnigram()) {
throw new ElasticSearchIllegalArgumentException("The default candidate generator for phrase suggest can't operate on field: [" + suggestion.getField() + "] since it doesn't emit unigrams. If this is intentional try to set the candidate generator field explicitly");
}
// use a default generator on the same field
DirectCandidateGenerator generator = new DirectCandidateGenerator();
generator.setField(suggestion.getField());
suggestion.addGenerator(generator);
}
}
return suggestion;
}
public void parseSmoothingModel(XContentParser parser, PhraseSuggestionContext suggestion, String fieldName) throws IOException {
XContentParser.Token token;
while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
if (token == XContentParser.Token.FIELD_NAME) {
fieldName = parser.currentName();
if ("linear".equals(fieldName)) {
ensureNoSmoothing(suggestion);
final double[] lambdas = new double[3];
while ((token = parser.nextToken()) != Token.END_OBJECT) {
if (token == XContentParser.Token.FIELD_NAME) {
fieldName = parser.currentName();
}
if (token.isValue()) {
if ("trigram_lambda".equals(fieldName) || "trigramLambda".equals(fieldName)) {
lambdas[0] = parser.doubleValue();
if (lambdas[0] < 0) {
throw new ElasticSearchIllegalArgumentException("trigram_lambda must be positive");
}
} else if ("bigram_lambda".equals(fieldName) || "bigramLambda".equals(fieldName)) {
lambdas[1] = parser.doubleValue();
if (lambdas[1] < 0) {
throw new ElasticSearchIllegalArgumentException("bigram_lambda must be positive");
}
} else if ("unigram_lambda".equals(fieldName) || "unigramLambda".equals(fieldName)) {
lambdas[2] = parser.doubleValue();
if (lambdas[2] < 0) {
throw new ElasticSearchIllegalArgumentException("unigram_lambda must be positive");
}
} else {
throw new ElasticSearchIllegalArgumentException(
"suggester[phrase][smoothing][linear] doesn't support field [" + fieldName + "]");
}
}
}
double sum = 0.0d;
for (int i = 0; i < lambdas.length; i++) {
sum += lambdas[i];
}
if (Math.abs(sum - 1.0) > 0.001) {
throw new ElasticSearchIllegalArgumentException("linear smoothing lambdas must sum to 1");
}
suggestion.setModel(new WordScorer.WordScorerFactory() {
@Override
public WordScorer newScorer(IndexReader reader, String field, double realWordLikelyhood, BytesRef separator)
throws IOException {
return new LinearInterpoatingScorer(reader, field, realWordLikelyhood, separator, lambdas[0], lambdas[1],
lambdas[2]);
}
});
} else if ("laplace".equals(fieldName)) {
ensureNoSmoothing(suggestion);
double theAlpha = 0.5;
while ((token = parser.nextToken()) != Token.END_OBJECT) {
if (token == XContentParser.Token.FIELD_NAME) {
fieldName = parser.currentName();
}
if (token.isValue() && "alpha".equals(fieldName)) {
theAlpha = parser.doubleValue();
}
}
final double alpha = theAlpha;
suggestion.setModel(new WordScorer.WordScorerFactory() {
@Override
public WordScorer newScorer(IndexReader reader, String field, double realWordLikelyhood, BytesRef separator)
throws IOException {
return new LaplaceScorer(reader, field, realWordLikelyhood, separator, alpha);
}
});
} else if ("stupid_backoff".equals(fieldName) || "stupidBackoff".equals(fieldName)) {
ensureNoSmoothing(suggestion);
double theDiscount = 0.4;
while ((token = parser.nextToken()) != Token.END_OBJECT) {
if (token == XContentParser.Token.FIELD_NAME) {
fieldName = parser.currentName();
}
if (token.isValue() && "discount".equals(fieldName)) {
theDiscount = parser.doubleValue();
}
}
final double discount = theDiscount;
suggestion.setModel(new WordScorer.WordScorerFactory() {
@Override
public WordScorer newScorer(IndexReader reader, String field, double realWordLikelyhood, BytesRef separator)
throws IOException {
return new StupidBackoffScorer(reader, field, realWordLikelyhood, separator, discount);
}
});
} else {
throw new ElasticSearchIllegalArgumentException("suggester[phrase] doesn't support object field [" + fieldName + "]");
}
}
}
}
private void ensureNoSmoothing(PhraseSuggestionContext suggestion) {
if (suggestion.model() != null) {
throw new ElasticSearchIllegalArgumentException("only one smoothing model supported");
}
}
private void verifyGenerator(PhraseSuggestionContext.DirectCandidateGenerator suggestion) {
// Verify options and set defaults
if (suggestion.field() == null) {
throw new ElasticSearchIllegalArgumentException("The required field option is missing");
}
}
private void parseCandidateGenerator(XContentParser parser, MapperService mapperService, String fieldName,
PhraseSuggestionContext.DirectCandidateGenerator generator) throws IOException {
if (!SuggestUtils.parseDirectSpellcheckerSettings(parser, fieldName, generator)) {
if ("field".equals(fieldName)) {
generator.setField(parser.text());
} else if ("size".equals(fieldName)) {
generator.size(parser.intValue());
} else if ("pre_filter".equals(fieldName) || "preFilter".equals(fieldName)) {
String analyzerName = parser.text();
Analyzer analyzer = mapperService.analysisService().analyzer(analyzerName);
if (analyzer == null) {
throw new ElasticSearchIllegalArgumentException("Analyzer [" + analyzerName + "] doesn't exists");
}
generator.preFilter(analyzer);
} else if ("post_filter".equals(fieldName) || "postFilter".equals(fieldName)) {
String analyzerName = parser.text();
Analyzer analyzer = mapperService.analysisService().analyzer(analyzerName);
if (analyzer == null) {
throw new ElasticSearchIllegalArgumentException("Analyzer [" + analyzerName + "] doesn't exists");
}
generator.postFilter(analyzer);
} else {
throw new ElasticSearchIllegalArgumentException("CandidateGenerator doesn't support [" + fieldName + "]");
}
}
}
}
