org.elasticsearch.util.lucene.search.Queries Maven / Gradle / Ivy
/*
* 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.util.lucene.search;
import org.apache.lucene.search.*;
import java.lang.reflect.Field;
import java.util.List;
/**
* @author kimchy (shay.banon)
*/
public class Queries {
private final static Field disjuncts;
static {
Field disjunctsX;
try {
disjunctsX = DisjunctionMaxQuery.class.getDeclaredField("disjuncts");
disjunctsX.setAccessible(true);
} catch (Exception e) {
disjunctsX = null;
}
disjuncts = disjunctsX;
}
public static List disMaxClauses(DisjunctionMaxQuery query) {
try {
return (List) disjuncts.get(query);
} catch (IllegalAccessException e) {
return null;
}
}
/**
* Optimizes the given query and returns the optimized version of it.
*/
public static Query optimizeQuery(Query q) {
if (q instanceof BooleanQuery) {
return optimizeBooleanQuery((BooleanQuery) q);
}
return q;
}
public static BooleanQuery optimizeBooleanQuery(BooleanQuery q) {
BooleanQuery optimized = new BooleanQuery(q.isCoordDisabled());
optimized.setMinimumNumberShouldMatch(q.getMinimumNumberShouldMatch());
optimizeBooleanQuery(optimized, q);
return optimized;
}
public static void optimizeBooleanQuery(BooleanQuery optimized, BooleanQuery q) {
for (BooleanClause clause : q.clauses()) {
Query cq = clause.getQuery();
cq.setBoost(cq.getBoost() * q.getBoost());
if (cq instanceof BooleanQuery && !clause.isRequired() && !clause.isProhibited()) {
optimizeBooleanQuery(optimized, (BooleanQuery) cq);
} else {
optimized.add(clause);
}
}
}
public static boolean isNegativeQuery(Query q) {
if (!(q instanceof BooleanQuery)) {
return false;
}
List clauses = ((BooleanQuery) q).clauses();
if (clauses.isEmpty()) {
return false;
}
for (BooleanClause clause : clauses) {
if (!clause.isProhibited()) return false;
}
return true;
}
public static Query fixNegativeQueryIfNeeded(Query q) {
if (isNegativeQuery(q)) {
BooleanQuery newBq = (BooleanQuery) q.clone();
newBq.add(new MatchAllDocsQuery(), BooleanClause.Occur.MUST);
return newBq;
}
return q;
}
}