| /* |
| * 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.expression; |
| |
| import org.apache.pig.data.DataType; |
| import org.apache.pig.impl.logicalLayer.FrontendException; |
| import org.apache.pig.newplan.Operator; |
| import org.apache.pig.newplan.OperatorPlan; |
| import org.apache.pig.newplan.PlanVisitor; |
| import org.apache.pig.newplan.logical.relational.LogicalSchema; |
| import org.apache.pig.parser.SourceLocation; |
| |
| public class IsNullExpression extends UnaryExpression { |
| |
| public IsNullExpression(OperatorPlan plan, LogicalExpression exp) { |
| super("IsNull", plan, exp); |
| } |
| |
| @Override |
| public void accept(PlanVisitor v) throws FrontendException { |
| if (!(v instanceof LogicalExpressionVisitor)) { |
| throw new FrontendException("Expected LogicalExpressionVisitor", 2222); |
| } |
| ((LogicalExpressionVisitor)v).visit(this); |
| } |
| |
| @Override |
| public boolean isEqual(Operator other) throws FrontendException { |
| if (other != null && other instanceof IsNullExpression) { |
| IsNullExpression of = (IsNullExpression)other; |
| return getExpression().isEqual( of.getExpression() ); |
| } else { |
| return false; |
| } |
| } |
| |
| @Override |
| public LogicalSchema.LogicalFieldSchema getFieldSchema() throws FrontendException { |
| if (fieldSchema!=null) |
| return fieldSchema; |
| fieldSchema = new LogicalSchema.LogicalFieldSchema(null, null, DataType.BOOLEAN); |
| uidOnlyFieldSchema = fieldSchema.mergeUid(uidOnlyFieldSchema); |
| return fieldSchema; |
| } |
| |
| @Override |
| public LogicalExpression deepCopy(LogicalExpressionPlan lgExpPlan) throws FrontendException{ |
| LogicalExpression copy = new IsNullExpression ( |
| lgExpPlan, |
| this.getExpression().deepCopy(lgExpPlan)); |
| copy.setLocation( new SourceLocation( location ) ); |
| return copy; |
| } |
| |
| } |