/*
 * Copyright 2009-2010 by The Regents of the University of California
 * 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 from
 * 
 *     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 edu.uci.ics.hyracks.algebricks.compiler.rewriter.rulecontrollers;

import java.util.Collection;

import org.apache.commons.lang3.mutable.Mutable;

import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalOperator;
import edu.uci.ics.hyracks.algebricks.core.rewriter.base.AbstractRuleController;
import edu.uci.ics.hyracks.algebricks.core.rewriter.base.IAlgebraicRewriteRule;

/**
 * Runs rules sequentially (round-robin), until one iteration over all rules
 * produces no change.
 * 
 * @author Nicola
 */
public class SequentialFixpointRuleController extends AbstractRuleController {

    private boolean fullDfs;

    public SequentialFixpointRuleController(boolean fullDfs) {
        super();
        this.fullDfs = fullDfs;
    }

    @Override
    public boolean rewriteWithRuleCollection(Mutable<ILogicalOperator> root,
            Collection<IAlgebraicRewriteRule> ruleCollection) throws AlgebricksException {
        boolean anyRuleFired = false;
        boolean anyChange = false;
        do {
            anyChange = false;
            for (IAlgebraicRewriteRule rule : ruleCollection) {
                boolean ruleFired = rewriteOperatorRef(root, rule, true, fullDfs);
                if (ruleFired) {
                    anyChange = true;
                    anyRuleFired = true;
                }
            }
        } while (anyChange);
        return anyRuleFired;
    }

}