| /* |
| * 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 org.apache.pig.PigException; |
| import org.apache.pig.impl.logicalLayer.FrontendException; |
| import org.apache.pig.impl.plan.VisitorException; |
| import org.apache.pig.newplan.DependencyOrderWalker; |
| import org.apache.pig.newplan.OperatorPlan; |
| import org.apache.pig.newplan.PlanWalker; |
| import org.apache.pig.newplan.ReverseDependencyOrderWalker; |
| import org.apache.pig.newplan.logical.expression.LogicalExpressionPlan; |
| import org.apache.pig.newplan.logical.expression.LogicalExpressionVisitor; |
| import org.apache.pig.newplan.logical.expression.ProjectExpression; |
| import org.apache.pig.newplan.logical.relational.LOFilter; |
| import org.apache.pig.newplan.logical.relational.LOLimit; |
| import org.apache.pig.newplan.logical.relational.LogicalRelationalNodesVisitor; |
| |
| /** |
| * This validator checks the correctness of use of scalar variables in logical |
| * operators. It assesses the validity of the expression by making sure there is |
| * no projection in it. Currently it works for Limit and Sample (see PIG-1926) |
| * |
| */ |
| public class ScalarVariableValidator extends LogicalRelationalNodesVisitor { |
| public static final String ERR_MSG_SCALAR = "Expression in Limit/Sample should be scalar"; |
| |
| public ScalarVariableValidator(OperatorPlan plan) throws FrontendException { |
| super(plan, new DependencyOrderWalker(plan)); |
| } |
| |
| @Override |
| public void visit(LOLimit limit) throws FrontendException { |
| LogicalExpressionPlan expression = limit.getLimitPlan(); |
| if (expression != null) { |
| ProjectFinder pf = new ProjectFinder(expression, |
| new ReverseDependencyOrderWalker(expression)); |
| pf.visit(); |
| if (pf.found()) { |
| int errCode = 1131; |
| throw new VisitorException(limit, ERR_MSG_SCALAR, errCode, |
| PigException.INPUT); |
| } |
| } |
| } |
| |
| @Override |
| public void visit(LOFilter filter) throws FrontendException { |
| LogicalExpressionPlan expression = filter.getFilterPlan(); |
| if (expression != null) { |
| // if it is a Sample, the expression must be scalar |
| if (filter.isSample()) { |
| ProjectFinder pf = new ProjectFinder(expression, |
| new ReverseDependencyOrderWalker(expression)); |
| pf.visit(); |
| if (pf.found()) { |
| int errCode = 1131; |
| throw new VisitorException(filter, ERR_MSG_SCALAR, errCode, |
| PigException.INPUT); |
| } |
| } |
| } |
| } |
| |
| public static class ProjectFinder extends LogicalExpressionVisitor { |
| private boolean foundProject; |
| |
| public boolean found() { |
| return foundProject; |
| } |
| |
| protected ProjectFinder(OperatorPlan p, PlanWalker walker) |
| throws FrontendException { |
| super(p, walker); |
| } |
| |
| @Override |
| public void visit(ProjectExpression project) { |
| foundProject = true; |
| } |
| } |
| } |