org.elasticsearch.common.lucene.search.Queries Maven / Gradle / Ivy
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* Licensed to ElasticSearch and Shay Banon under one
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* 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.common.lucene.search;
import org.apache.lucene.search.*;
import org.elasticsearch.common.Nullable;
import java.lang.reflect.Field;
import java.util.List;
import java.util.regex.Pattern;
/**
*
*/
public class Queries {
// We don't use MatchAllDocsQuery, its slower than the one below ... (much slower)
public final static Query MATCH_ALL_QUERY = new XConstantScoreQuery(new MatchAllDocsFilter());
public final static Query NO_MATCH_QUERY = MatchNoDocsQuery.INSTANCE;
/**
* A match all docs filter. Note, requires no caching!.
*/
public final static Filter MATCH_ALL_FILTER = new MatchAllDocsFilter();
public final static Filter MATCH_NO_FILTER = new MatchNoDocsFilter();
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) {
BooleanQuery booleanQuery = (BooleanQuery) q;
BooleanClause[] clauses = booleanQuery.getClauses();
if (clauses.length == 1) {
BooleanClause clause = clauses[0];
if (clause.getOccur() == BooleanClause.Occur.MUST) {
Query query = clause.getQuery();
query.setBoost(booleanQuery.getBoost() * query.getBoost());
return optimizeQuery(query);
}
if (clause.getOccur() == BooleanClause.Occur.SHOULD && booleanQuery.getMinimumNumberShouldMatch() > 0) {
Query query = clause.getQuery();
query.setBoost(booleanQuery.getBoost() * query.getBoost());
return optimizeQuery(query);
}
}
}
return q;
}
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(MATCH_ALL_QUERY, BooleanClause.Occur.MUST);
return newBq;
}
return q;
}
public static boolean isConstantMatchAllQuery(Query query) {
if (query == Queries.MATCH_ALL_QUERY) {
return true;
}
if (query instanceof XConstantScoreQuery) {
XConstantScoreQuery scoreQuery = (XConstantScoreQuery) query;
if (scoreQuery.getFilter() instanceof MatchAllDocsFilter) {
return true;
}
}
return false;
}
public static void applyMinimumShouldMatch(BooleanQuery query, @Nullable String minimumShouldMatch) {
if (minimumShouldMatch == null) {
return;
}
int optionalClauses = 0;
for (BooleanClause c : query.clauses()) {
if (c.getOccur() == BooleanClause.Occur.SHOULD) {
optionalClauses++;
}
}
int msm = calculateMinShouldMatch(optionalClauses, minimumShouldMatch);
if (0 < msm) {
query.setMinimumNumberShouldMatch(msm);
}
}
private static Pattern spaceAroundLessThanPattern = Pattern.compile("(\\s+<\\s*)|(\\s*<\\s+)");
private static Pattern spacePattern = Pattern.compile(" ");
private static Pattern lessThanPattern = Pattern.compile("<");
public static int calculateMinShouldMatch(int optionalClauseCount, String spec) {
int result = optionalClauseCount;
spec = spec.trim();
if (-1 < spec.indexOf("<")) {
/* we have conditional spec(s) */
spec = spaceAroundLessThanPattern.matcher(spec).replaceAll("<");
for (String s : spacePattern.split(spec)) {
String[] parts = lessThanPattern.split(s, 0);
int upperBound = Integer.parseInt(parts[0]);
if (optionalClauseCount <= upperBound) {
return result;
} else {
result = calculateMinShouldMatch
(optionalClauseCount, parts[1]);
}
}
return result;
}
/* otherwise, simple expresion */
if (-1 < spec.indexOf('%')) {
/* percentage - assume the % was the last char. If not, let Integer.parseInt fail. */
spec = spec.substring(0, spec.length() - 1);
int percent = Integer.parseInt(spec);
float calc = (result * percent) * (1 / 100f);
result = calc < 0 ? result + (int) calc : (int) calc;
} else {
int calc = Integer.parseInt(spec);
result = calc < 0 ? result + calc : calc;
}
return (optionalClauseCount < result ?
optionalClauseCount : (result < 0 ? 0 : result));
}
}