/*
* Copyright (c) 2008-2017, Hazelcast, Inc. All Rights Reserved.
*
* Licensed 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 com.hazelcast.query.impl.predicates;
import com.hazelcast.query.Predicate;
import com.hazelcast.query.VisitablePredicate;
import com.hazelcast.query.impl.Indexes;
/**
* Rule based optimizer. It chains {@link Visitor}s to rewrite query.
*
*/
public final class RuleBasedQueryOptimizer implements QueryOptimizer {
private final Visitor betweenVisitor = new BetweenVisitor();
private final Visitor flatteningVisitor = new FlatteningVisitor();
private final Visitor orToInVisitor = new OrToInVisitor();
public <K, V> Predicate<K, V> optimize(Predicate<K, V> predicate, Indexes indexes) {
Predicate optimized = predicate;
if (optimized instanceof VisitablePredicate) {
optimized = ((VisitablePredicate) optimized).accept(flatteningVisitor, indexes);
}
if (optimized instanceof VisitablePredicate) {
optimized = ((VisitablePredicate) optimized).accept(betweenVisitor, indexes);
}
if (optimized instanceof VisitablePredicate) {
optimized = ((VisitablePredicate) optimized).accept(orToInVisitor, indexes);
}
return optimized;
}
}