| /* |
| * 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.List; |
| |
| import org.apache.pig.data.DataType; |
| import org.apache.pig.impl.logicalLayer.FrontendException; |
| import org.apache.pig.impl.plan.PlanValidationException; |
| import org.apache.pig.newplan.DependencyOrderWalker; |
| import org.apache.pig.newplan.OperatorPlan; |
| import org.apache.pig.newplan.logical.expression.DereferenceExpression; |
| import org.apache.pig.newplan.logical.expression.LogicalExpression; |
| 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.optimizer.AllExpressionVisitor; |
| import org.apache.pig.newplan.logical.relational.LogicalSchema; |
| |
| /** |
| * Logical plan visitor which will convert all column alias references to column |
| * indexes, using the underlying anonymous expression plan visitor. |
| */ |
| public class ColumnAliasConversionVisitor extends AllExpressionVisitor { |
| |
| public ColumnAliasConversionVisitor(OperatorPlan plan) throws FrontendException { |
| super( plan, new DependencyOrderWalker( plan ) ); |
| } |
| |
| @Override |
| protected LogicalExpressionVisitor getVisitor(LogicalExpressionPlan exprPlan) |
| throws FrontendException { |
| return new LogicalExpressionVisitor( exprPlan, new DependencyOrderWalker( exprPlan ) ) { |
| @Override |
| public void visit(ProjectExpression expr) throws FrontendException { |
| expr.setColumnNumberFromAlias(); |
| } |
| |
| public void visit(DereferenceExpression expr) throws FrontendException { |
| List<Object> rawCols = expr.getRawColumns(); |
| if( rawCols.isEmpty() ) { |
| return; |
| } |
| |
| List<Integer> cols = new ArrayList<Integer>( rawCols.size() ); |
| LogicalExpressionPlan plan = (LogicalExpressionPlan)expr.getPlan(); |
| LogicalExpression pred = (LogicalExpression)plan.getSuccessors( expr ).get(0); |
| |
| LogicalSchema schema = null; |
| if( pred.getFieldSchema().type == DataType.BAG ) { |
| if( pred.getFieldSchema().schema != null ) { |
| schema = pred.getFieldSchema().schema.getField(0).schema; |
| if (schema!=null && schema.size()==1 && schema.getField(0).type==DataType.TUPLE) { |
| schema = schema.getField(0).schema; |
| } |
| } |
| } |
| else { |
| schema = pred.getFieldSchema().schema; |
| } |
| |
| int col = -1; |
| for( Object rc : rawCols ) { |
| if( rc instanceof Integer ) { |
| col = (Integer)rc; |
| if( schema != null && schema.size()!=0 && col >= schema.size() ) { |
| throw new PlanValidationException( expr, "Out of bound access. Trying to access non-existent column: " + |
| col + ". Schema " + schema.toString(false) + " has " + schema.size() + " column(s).", 1000 ); |
| } |
| cols.add( (Integer)rc ); |
| } else { |
| col = schema == null ? -1 : schema.getFieldPosition( (String)rc ); |
| if( col == -1 ) { |
| throw new PlanValidationException( expr, "Invalid field reference. Referenced field [" + |
| rc + "] does not exist in schema: " + (schema!=null?schema.toString(false):"") + "." , 1000); |
| } |
| cols.add( col ); |
| } |
| } |
| expr.setBagColumns( cols ); |
| } |
| }; |
| } |
| } |