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/*
* 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 com.google.common.collect.Sets;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.queries.TermsFilter;
import org.apache.lucene.search.BooleanClause;
import org.apache.lucene.search.BooleanQuery;
import org.apache.lucene.search.ConstantScoreQuery;
import org.apache.lucene.search.Query;
import org.apache.lucene.util.BytesRef;
import org.elasticsearch.ElasticsearchIllegalArgumentException;
import org.elasticsearch.action.termvector.MultiTermVectorsRequest;
import org.elasticsearch.action.termvector.TermVectorRequest;
import org.elasticsearch.common.Nullable;
import org.elasticsearch.common.ParseField;
import org.elasticsearch.common.Strings;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.lucene.search.MoreLikeThisQuery;
import org.elasticsearch.common.xcontent.XContentParser;
import org.elasticsearch.index.analysis.Analysis;
import org.elasticsearch.index.mapper.internal.UidFieldMapper;
import org.elasticsearch.index.search.morelikethis.MoreLikeThisFetchService;
import org.elasticsearch.search.internal.SearchContext;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import static org.elasticsearch.index.mapper.Uid.createUidAsBytes;
/**
*
*/
public class MoreLikeThisQueryParser implements QueryParser {
public static final String NAME = "mlt";
private MoreLikeThisFetchService fetchService = null;
public static class Fields {
public static final ParseField LIKE_TEXT = new ParseField("like_text");
public static final ParseField MIN_TERM_FREQ = new ParseField("min_term_freq");
public static final ParseField MAX_QUERY_TERMS = new ParseField("max_query_terms");
public static final ParseField MIN_WORD_LENGTH = new ParseField("min_word_length", "min_word_len");
public static final ParseField MAX_WORD_LENGTH = new ParseField("max_word_length", "max_word_len");
public static final ParseField MIN_DOC_FREQ = new ParseField("min_doc_freq");
public static final ParseField MAX_DOC_FREQ = new ParseField("max_doc_freq");
public static final ParseField BOOST_TERMS = new ParseField("boost_terms");
public static final ParseField MINIMUM_SHOULD_MATCH = new ParseField("minimum_should_match");
public static final ParseField PERCENT_TERMS_TO_MATCH = new ParseField("percent_terms_to_match").withAllDeprecated("minimum_should_match");
public static final ParseField FAIL_ON_UNSUPPORTED_FIELD = new ParseField("fail_on_unsupported_field");
public static final ParseField STOP_WORDS = new ParseField("stop_words");
public static final ParseField DOCUMENT_IDS = new ParseField("ids");
public static final ParseField DOCUMENTS = new ParseField("docs");
public static final ParseField INCLUDE = new ParseField("include");
public static final ParseField EXCLUDE = new ParseField("exclude");
}
public MoreLikeThisQueryParser() {
}
@Inject(optional = true)
public void setFetchService(@Nullable MoreLikeThisFetchService fetchService) {
this.fetchService = fetchService;
}
@Override
public String[] names() {
return new String[]{NAME, "more_like_this", "moreLikeThis"};
}
@Override
public Query parse(QueryParseContext parseContext) throws IOException, QueryParsingException {
XContentParser parser = parseContext.parser();
MoreLikeThisQuery mltQuery = new MoreLikeThisQuery();
mltQuery.setSimilarity(parseContext.searchSimilarity());
Analyzer analyzer = null;
List moreLikeFields = null;
boolean failOnUnsupportedField = true;
String queryName = null;
boolean include = false;
XContentParser.Token token;
String currentFieldName = null;
MultiTermVectorsRequest items = new MultiTermVectorsRequest();
while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
if (token == XContentParser.Token.FIELD_NAME) {
currentFieldName = parser.currentName();
} else if (token.isValue()) {
if (Fields.LIKE_TEXT.match(currentFieldName, parseContext.parseFlags())) {
mltQuery.setLikeText(parser.text());
} else if (Fields.MIN_TERM_FREQ.match(currentFieldName, parseContext.parseFlags())) {
mltQuery.setMinTermFrequency(parser.intValue());
} else if (Fields.MAX_QUERY_TERMS.match(currentFieldName, parseContext.parseFlags())) {
mltQuery.setMaxQueryTerms(parser.intValue());
} else if (Fields.MIN_DOC_FREQ.match(currentFieldName, parseContext.parseFlags())) {
mltQuery.setMinDocFreq(parser.intValue());
} else if (Fields.MAX_DOC_FREQ.match(currentFieldName, parseContext.parseFlags())) {
mltQuery.setMaxDocFreq(parser.intValue());
} else if (Fields.MIN_WORD_LENGTH.match(currentFieldName, parseContext.parseFlags())) {
mltQuery.setMinWordLen(parser.intValue());
} else if (Fields.MAX_WORD_LENGTH.match(currentFieldName, parseContext.parseFlags())) {
mltQuery.setMaxWordLen(parser.intValue());
} else if (Fields.BOOST_TERMS.match(currentFieldName, parseContext.parseFlags())) {
float boostFactor = parser.floatValue();
if (boostFactor != 0) {
mltQuery.setBoostTerms(true);
mltQuery.setBoostTermsFactor(boostFactor);
}
} else if (Fields.MINIMUM_SHOULD_MATCH.match(currentFieldName, parseContext.parseFlags())) {
mltQuery.setMinimumShouldMatch(parser.text());
} else if (Fields.PERCENT_TERMS_TO_MATCH.match(currentFieldName, parseContext.parseFlags())) {
mltQuery.setMinimumShouldMatch(Math.round(parser.floatValue() * 100) + "%");
} else if ("analyzer".equals(currentFieldName)) {
analyzer = parseContext.analysisService().analyzer(parser.text());
} else if ("boost".equals(currentFieldName)) {
mltQuery.setBoost(parser.floatValue());
} else if (Fields.FAIL_ON_UNSUPPORTED_FIELD.match(currentFieldName, parseContext.parseFlags())) {
failOnUnsupportedField = parser.booleanValue();
} else if ("_name".equals(currentFieldName)) {
queryName = parser.text();
} else if (Fields.INCLUDE.match(currentFieldName, parseContext.parseFlags())) {
include = parser.booleanValue();
} else if (Fields.EXCLUDE.match(currentFieldName, parseContext.parseFlags())) {
include = !parser.booleanValue();
} else {
throw new QueryParsingException(parseContext.index(), "[mlt] query does not support [" + currentFieldName + "]");
}
} else if (token == XContentParser.Token.START_ARRAY) {
if (Fields.STOP_WORDS.match(currentFieldName, parseContext.parseFlags())) {
Set stopWords = Sets.newHashSet();
while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
stopWords.add(parser.text());
}
mltQuery.setStopWords(stopWords);
} else if ("fields".equals(currentFieldName)) {
moreLikeFields = Lists.newLinkedList();
while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
moreLikeFields.add(parseContext.indexName(parser.text()));
}
} else if (Fields.DOCUMENT_IDS.match(currentFieldName, parseContext.parseFlags())) {
while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
if (!token.isValue()) {
throw new ElasticsearchIllegalArgumentException("ids array element should only contain ids");
}
items.add(newTermVectorRequest().id(parser.text()));
}
} else if (Fields.DOCUMENTS.match(currentFieldName, parseContext.parseFlags())) {
while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
if (token != XContentParser.Token.START_OBJECT) {
throw new ElasticsearchIllegalArgumentException("docs array element should include an object");
}
items.add(parseDocuments(parser));
}
} else {
throw new QueryParsingException(parseContext.index(), "[mlt] query does not support [" + currentFieldName + "]");
}
}
}
if (mltQuery.getLikeText() == null && items.isEmpty()) {
throw new QueryParsingException(parseContext.index(), "more_like_this requires at least 'like_text' or 'ids/docs' to be specified");
}
if (moreLikeFields != null && moreLikeFields.isEmpty()) {
throw new QueryParsingException(parseContext.index(), "more_like_this requires 'fields' to be non-empty");
}
// set analyzer
if (analyzer == null) {
analyzer = parseContext.mapperService().searchAnalyzer();
}
mltQuery.setAnalyzer(analyzer);
// set like text fields
boolean useDefaultField = (moreLikeFields == null);
if (useDefaultField) {
moreLikeFields = Lists.newArrayList(parseContext.defaultField());
}
// possibly remove unsupported fields
removeUnsupportedFields(moreLikeFields, analyzer, failOnUnsupportedField);
if (moreLikeFields.isEmpty()) {
return null;
}
mltQuery.setMoreLikeFields(moreLikeFields.toArray(Strings.EMPTY_ARRAY));
// support for named query
if (queryName != null) {
parseContext.addNamedQuery(queryName, mltQuery);
}
// handle items
if (!items.isEmpty()) {
// set default index, type and fields if not specified
for (TermVectorRequest item : items) {
if (item.index() == null) {
item.index(parseContext.index().name());
}
if (item.type() == null) {
if (parseContext.queryTypes().size() > 1) {
throw new QueryParsingException(parseContext.index(),
"ambiguous type for item with id: " + item.id() + " and index: " + item.index());
} else {
item.type(parseContext.queryTypes().iterator().next());
}
}
// default fields if not present but don't override for artificial docs
if (item.selectedFields() == null && item.doc() == null) {
if (useDefaultField) {
item.selectedFields("*");
} else {
item.selectedFields(moreLikeFields.toArray(new String[moreLikeFields.size()]));
}
}
}
// fetching the items with multi-termvectors API
items.copyContextAndHeadersFrom(SearchContext.current());
org.apache.lucene.index.Fields[] likeFields = fetchService.fetch(items);
mltQuery.setLikeText(likeFields);
BooleanQuery boolQuery = new BooleanQuery();
boolQuery.add(mltQuery, BooleanClause.Occur.SHOULD);
// exclude the items from the search
if (!include) {
handleExclude(boolQuery, items);
}
return boolQuery;
}
return mltQuery;
}
private TermVectorRequest newTermVectorRequest() {
return new TermVectorRequest()
.positions(false)
.offsets(false)
.payloads(false)
.fieldStatistics(false)
.termStatistics(false);
}
private TermVectorRequest parseDocuments(XContentParser parser) throws IOException {
TermVectorRequest termVectorRequest = newTermVectorRequest();
TermVectorRequest.parseRequest(termVectorRequest, parser);
return termVectorRequest;
}
private List removeUnsupportedFields(List moreLikeFields, Analyzer analyzer, boolean failOnUnsupportedField) throws IOException {
for (Iterator it = moreLikeFields.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();
}
}
}
return moreLikeFields;
}
private void handleExclude(BooleanQuery boolQuery, MultiTermVectorsRequest likeItems) {
// artificial docs get assigned a random id and should be disregarded
List uids = new ArrayList<>();
for (TermVectorRequest item : likeItems) {
if (item.doc() != null) {
continue;
}
uids.add(createUidAsBytes(item.type(), item.id()));
}
if (!uids.isEmpty()) {
TermsFilter filter = new TermsFilter(UidFieldMapper.NAME, uids.toArray(new BytesRef[0]));
ConstantScoreQuery query = new ConstantScoreQuery(filter);
boolQuery.add(query, BooleanClause.Occur.MUST_NOT);
}
}
}
