| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF 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.apache.pig.backend.hadoop.executionengine.util; |
| |
| import org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator; |
| import org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.ConstantExpression; |
| import org.apache.pig.backend.hadoop.executionengine.physicalLayer.plans.PhyPlanVisitor; |
| import org.apache.pig.backend.hadoop.executionengine.physicalLayer.plans.PhysicalPlan; |
| import org.apache.pig.impl.plan.DepthFirstWalker; |
| import org.apache.pig.impl.plan.VisitorException; |
| |
| public class ParallelConstantVisitor extends PhyPlanVisitor { |
| |
| private int rp; |
| |
| private boolean replaced = false; |
| |
| public ParallelConstantVisitor(PhysicalPlan plan, int rp) { |
| super(plan, new DepthFirstWalker<PhysicalOperator, PhysicalPlan>( |
| plan)); |
| this.rp = rp; |
| } |
| |
| @Override |
| public void visitConstant(ConstantExpression cnst) throws VisitorException { |
| Object obj = cnst.getValue(); |
| if (obj instanceof Integer) { |
| if (replaced) { |
| // sample job should have only one ConstantExpression |
| throw new VisitorException("Invalid reduce plan: more " + |
| "than one ConstantExpression found in sampling job"); |
| } |
| cnst.setValue(rp); |
| cnst.setRequestedParallelism(rp); |
| replaced = true; |
| } |
| } |
| } |