| /* |
| * 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.rewriter.rules; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| import org.apache.commons.lang3.mutable.Mutable; |
| import org.apache.commons.lang3.mutable.MutableObject; |
| |
| import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException; |
| import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalExpression; |
| import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalOperator; |
| import edu.uci.ics.hyracks.algebricks.core.algebra.base.IOptimizationContext; |
| import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalOperatorTag; |
| import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.AbstractLogicalOperator; |
| import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.SelectOperator; |
| import edu.uci.ics.hyracks.algebricks.core.rewriter.base.IAlgebraicRewriteRule; |
| |
| public class BreakSelectIntoConjunctsRule implements IAlgebraicRewriteRule { |
| |
| private List<Mutable<ILogicalExpression>> conjs = new ArrayList<Mutable<ILogicalExpression>>(); |
| |
| @Override |
| public boolean rewritePost(Mutable<ILogicalOperator> opRef, IOptimizationContext context) { |
| return false; |
| } |
| |
| @Override |
| public boolean rewritePre(Mutable<ILogicalOperator> opRef, IOptimizationContext context) throws AlgebricksException { |
| AbstractLogicalOperator op = (AbstractLogicalOperator) opRef.getValue(); |
| if (op.getOperatorTag() != LogicalOperatorTag.SELECT) { |
| return false; |
| } |
| SelectOperator select = (SelectOperator) op; |
| |
| ILogicalExpression cond = select.getCondition().getValue(); |
| |
| conjs.clear(); |
| if (!cond.splitIntoConjuncts(conjs)) { |
| return false; |
| } |
| |
| Mutable<ILogicalOperator> childOfSelect = select.getInputs().get(0); |
| boolean fst = true; |
| ILogicalOperator botOp = select; |
| ILogicalExpression firstExpr = null; |
| for (Mutable<ILogicalExpression> eRef : conjs) { |
| ILogicalExpression e = eRef.getValue(); |
| if (fst) { |
| fst = false; |
| firstExpr = e; |
| } else { |
| SelectOperator newSelect = new SelectOperator(new MutableObject<ILogicalExpression>(e)); |
| List<Mutable<ILogicalOperator>> botInpList = botOp.getInputs(); |
| botInpList.clear(); |
| botInpList.add(new MutableObject<ILogicalOperator>(newSelect)); |
| context.computeAndSetTypeEnvironmentForOperator(botOp); |
| botOp = newSelect; |
| } |
| } |
| botOp.getInputs().add(childOfSelect); |
| select.getCondition().setValue(firstExpr); |
| context.computeAndSetTypeEnvironmentForOperator(botOp); |
| context.computeAndSetTypeEnvironmentForOperator(select); |
| |
| return true; |
| } |
| } |