/*
* Licensed to Elasticsearch 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.index.query;
import com.google.common.collect.Lists;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.sandbox.queries.FuzzyLikeThisQuery;
import org.apache.lucene.search.Query;
import org.elasticsearch.ElasticsearchIllegalArgumentException;
import org.elasticsearch.common.ParseField;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.unit.Fuzziness;
import org.elasticsearch.common.xcontent.XContentParser;
import org.elasticsearch.index.analysis.Analysis;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;
/**
* <pre>
* {
* fuzzy_like_this : {
* maxNumTerms : 12,
* boost : 1.1,
* fields : ["field1", "field2"]
* likeText : "..."
* }
* }
* </pre>
*/
public class FuzzyLikeThisQueryParser implements QueryParser {
public static final String NAME = "flt";
private static final ParseField FUZZINESS = Fuzziness.FIELD.withDeprecation("min_similarity");
@Inject
public FuzzyLikeThisQueryParser() {
}
@Override
public String[] names() {
return new String[]{NAME, "fuzzy_like_this", "fuzzyLikeThis"};
}
@Override
public Query parse(QueryParseContext parseContext) throws IOException, QueryParsingException {
XContentParser parser = parseContext.parser();
int maxNumTerms = 25;
float boost = 1.0f;
List<String> fields = null;
String likeText = null;
Fuzziness fuzziness = Fuzziness.TWO;
int prefixLength = 0;
boolean ignoreTF = false;
Analyzer analyzer = null;
boolean failOnUnsupportedField = true;
String queryName = null;
XContentParser.Token token;
String currentFieldName = null;
while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
if (token == XContentParser.Token.FIELD_NAME) {
currentFieldName = parser.currentName();
} else if (token.isValue()) {
if ("like_text".equals(currentFieldName) || "likeText".equals(currentFieldName)) {
likeText = parser.text();
} else if ("max_query_terms".equals(currentFieldName) || "maxQueryTerms".equals(currentFieldName)) {
maxNumTerms = parser.intValue();
} else if ("boost".equals(currentFieldName)) {
boost = parser.floatValue();
} else if ("ignore_tf".equals(currentFieldName) || "ignoreTF".equals(currentFieldName)) {
ignoreTF = parser.booleanValue();
} else if (FUZZINESS.match(currentFieldName, parseContext.parseFlags())) {
fuzziness = Fuzziness.parse(parser);
} else if ("prefix_length".equals(currentFieldName) || "prefixLength".equals(currentFieldName)) {
prefixLength = parser.intValue();
} else if ("analyzer".equals(currentFieldName)) {
analyzer = parseContext.analysisService().analyzer(parser.text());
} else if ("fail_on_unsupported_field".equals(currentFieldName) || "failOnUnsupportedField".equals(currentFieldName)) {
failOnUnsupportedField = parser.booleanValue();
} else if ("_name".equals(currentFieldName)) {
queryName = parser.text();
} else {
throw new QueryParsingException(parseContext.index(), "[flt] query does not support [" + currentFieldName + "]");
}
} else if (token == XContentParser.Token.START_ARRAY) {
if ("fields".equals(currentFieldName)) {
fields = Lists.newLinkedList();
while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
fields.add(parseContext.indexName(parser.text()));
}
} else {
throw new QueryParsingException(parseContext.index(), "[flt] query does not support [" + currentFieldName + "]");
}
}
}
if (likeText == null) {
throw new QueryParsingException(parseContext.index(), "fuzzy_like_this requires 'like_text' to be specified");
}
if (analyzer == null) {
analyzer = parseContext.mapperService().searchAnalyzer();
}
FuzzyLikeThisQuery query = new FuzzyLikeThisQuery(maxNumTerms, analyzer);
if (fields == null) {
fields = Lists.newArrayList(parseContext.defaultField());
} else if (fields.isEmpty()) {
throw new QueryParsingException(parseContext.index(), "fuzzy_like_this requires 'fields' to be non-empty");
}
for (Iterator<String> it = fields.iterator(); it.hasNext(); ) {
final String fieldName = it.next();
if (!Analysis.generatesCharacterTokenStream(analyzer, fieldName)) {
if (failOnUnsupportedField) {
throw new ElasticsearchIllegalArgumentException("more_like_this doesn't support binary/numeric fields: [" + fieldName + "]");
} else {
it.remove();
}
}
}
if (fields.isEmpty()) {
return null;
}
float minSimilarity = fuzziness.asFloat();
if (minSimilarity >= 1.0f && minSimilarity != (int)minSimilarity) {
throw new ElasticsearchIllegalArgumentException("fractional edit distances are not allowed");
}
if (minSimilarity < 0.0f) {
throw new ElasticsearchIllegalArgumentException("minimumSimilarity cannot be less than 0");
}
for (String field : fields) {
query.addTerms(likeText, field, minSimilarity, prefixLength);
}
query.setBoost(boost);
query.setIgnoreTF(ignoreTF);
if (queryName != null) {
parseContext.addNamedQuery(queryName, query);
}
return query;
}
}