com.hazelcast.query.impl.predicates.RuleBasedQueryOptimizer Maven / Gradle / Ivy

/*
 * Copyright (c) 2008-2018, 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  Predicate optimize(Predicate 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;
    }
}