/*
* Licensed to Elastic Search and Shay Banon under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Elastic Search 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 org.apache.lucene.search.DeletionAwareConstantScoreQuery;
import org.apache.lucene.search.Filter;
import org.apache.lucene.search.FilteredQuery;
import org.apache.lucene.search.Query;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.lucene.search.Queries;
import org.elasticsearch.common.xcontent.XContentParser;
import org.elasticsearch.index.cache.filter.support.CacheKeyFilter;
import java.io.IOException;
/**
* @author kimchy (shay.banon)
*/
public class FilteredQueryParser implements QueryParser {
public static final String NAME = "filtered";
@Inject public FilteredQueryParser() {
}
@Override public String[] names() {
return new String[]{NAME};
}
@Override public Query parse(QueryParseContext parseContext) throws IOException, QueryParsingException {
XContentParser parser = parseContext.parser();
Query query = null;
Filter filter = null;
float boost = 1.0f;
boolean cache = false;
CacheKeyFilter.Key cacheKey = null;
String currentFieldName = null;
XContentParser.Token token;
while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
if (token == XContentParser.Token.FIELD_NAME) {
currentFieldName = parser.currentName();
} else if (token == XContentParser.Token.START_OBJECT) {
if ("query".equals(currentFieldName)) {
query = parseContext.parseInnerQuery();
} else if ("filter".equals(currentFieldName)) {
filter = parseContext.parseInnerFilter();
}
} else if (token.isValue()) {
if ("boost".equals(currentFieldName)) {
boost = parser.floatValue();
} else if ("_cache".equals(currentFieldName)) {
cache = parser.booleanValue();
} else if ("_cache_key".equals(currentFieldName) || "_cacheKey".equals(currentFieldName)) {
cacheKey = new CacheKeyFilter.Key(parser.text());
}
}
}
if (query == null) {
throw new QueryParsingException(parseContext.index(), "[filtered] requires 'query' element");
}
if (filter == null) {
throw new QueryParsingException(parseContext.index(), "[filtered] requires 'filter' element");
}
// cache if required
if (cache) {
filter = parseContext.cacheFilter(filter, cacheKey);
}
// if its a match_all query, use constant_score
if (Queries.isMatchAllQuery(query)) {
Query q = new DeletionAwareConstantScoreQuery(filter);
q.setBoost(boost);
return q;
}
// TODO
// With the way filtered queries work today, both query and filter advance (one at a time)
// to get hits. Since all filters support random access, it might make sense to use that.
// But, it make more sense to apply it down at the postings level then letting the query
// construct doc ids and extract it.
// This might be possible in lucene 4.0.
// More info:
// - https://issues.apache.org/jira/browse/LUCENE-1536
// - http://chbits.blogspot.com/2010/09/fast-search-filters-using-flex.html
FilteredQuery filteredQuery = new FilteredQuery(query, filter);
filteredQuery.setBoost(boost);
return filteredQuery;
}
}