| /* |
| * 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.List; |
| |
| import org.apache.pig.impl.logicalLayer.FrontendException; |
| import org.apache.pig.impl.util.Pair; |
| import org.apache.pig.newplan.Operator; |
| import org.apache.pig.newplan.logical.expression.LogicalExpressionPlan; |
| import org.apache.pig.newplan.logical.expression.ProjectExpression; |
| import org.apache.pig.newplan.logical.relational.LogicalRelationalOperator; |
| import org.apache.pig.newplan.logical.relational.LogicalSchema; |
| |
| /** |
| * Util function(s) for project-(star/range) expansion |
| */ |
| public class ProjectStarExpanderUtil{ |
| |
| /** |
| * If the argument project is a project-star or project-range that |
| * can be expanded, find the position of first and last columns |
| * it should project |
| * @param expPlan |
| * @param proj |
| * @return pair that has the first and last columns that need to be projected |
| * @throws FrontendException |
| */ |
| static Pair<Integer, Integer> getProjectStartEndCols( |
| LogicalExpressionPlan expPlan, ProjectExpression proj) |
| throws FrontendException { |
| |
| // get the input schema first |
| |
| LogicalRelationalOperator relOp = proj.getAttachedRelationalOp(); |
| |
| // list of inputs of attached relation |
| List<Operator> inputRels = relOp.getPlan().getPredecessors(relOp); |
| |
| //the relation that is input to this project |
| LogicalRelationalOperator inputRel = |
| (LogicalRelationalOperator) inputRels.get(proj.getInputNum()); |
| |
| LogicalSchema inputSchema = inputRel.getSchema(); |
| |
| |
| if(inputSchema == null && |
| (proj.isProjectStar() || (proj.isRangeProject() && proj.getEndCol() == -1)) |
| ){ |
| // can't expand if input schema is null and it is a project-star |
| // or project-range-until-end |
| return null; |
| } |
| |
| //find first and last column in input schema to be projected |
| int firstProjCol; |
| int lastProjCol; |
| |
| //the range values are set in the project in LOInnerLoad |
| if(proj.isRangeProject()){ |
| proj.setColumnNumberFromAlias(); |
| firstProjCol = proj.getStartCol(); |
| |
| if(proj.getEndCol() >= 0) |
| lastProjCol = proj.getEndCol(); |
| else |
| lastProjCol = inputSchema.size() - 1; |
| }else{ |
| //project-star |
| firstProjCol = 0; |
| lastProjCol = inputSchema.size() - 1; |
| } |
| return new Pair<Integer, Integer>(firstProjCol, lastProjCol); |
| |
| } |
| |
| |
| |
| } |