| /* |
| * 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.newplan.logical.visitor; |
| |
| import java.util.ArrayList; |
| import java.util.Iterator; |
| import java.util.List; |
| |
| import org.apache.pig.impl.logicalLayer.FrontendException; |
| import org.apache.pig.newplan.DependencyOrderWalker; |
| import org.apache.pig.newplan.Operator; |
| import org.apache.pig.newplan.OperatorPlan; |
| import org.apache.pig.newplan.logical.relational.LOForEach; |
| import org.apache.pig.newplan.logical.relational.LOGenerate; |
| import org.apache.pig.newplan.logical.relational.LogicalPlan; |
| import org.apache.pig.newplan.logical.relational.LogicalRelationalNodesVisitor; |
| |
| public class DanglingNestedNodeRemover extends LogicalRelationalNodesVisitor { |
| |
| public DanglingNestedNodeRemover(OperatorPlan plan) |
| throws FrontendException { |
| super(plan, new DependencyOrderWalker(plan)); |
| } |
| |
| @Override |
| public void visit(LOForEach foreach) throws FrontendException { |
| LogicalPlan innerPlan = foreach.getInnerPlan(); |
| List<Operator> opsToRemove = new ArrayList<Operator>(); |
| Iterator<Operator> ops = innerPlan.getOperators(); |
| |
| while (ops.hasNext()) { |
| Operator op = ops.next(); |
| // Check if op leads to LOGenerate, otherwise, candidate to remove |
| Operator currentOp = op; |
| boolean endWithNoLOGenerate = false; |
| while (!(currentOp instanceof LOGenerate)) { |
| if (innerPlan.getSuccessors(currentOp)==null) { |
| endWithNoLOGenerate = true; |
| break; |
| } |
| currentOp = innerPlan.getSuccessors(currentOp).get(0); |
| } |
| if (endWithNoLOGenerate) |
| opsToRemove.add(op); |
| } |
| |
| for (Operator op : opsToRemove) { |
| innerPlan.removeAndReconnect(op); |
| } |
| } |
| } |