| /* |
| * 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.PigException; |
| 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.Util; |
| import org.apache.pig.newplan.logical.relational.LogicalSchema.LogicalFieldSchema; |
| import org.apache.pig.parser.SourceLocation; |
| |
| /** |
| * A constant |
| * |
| */ |
| public class ConstantExpression extends ColumnExpression { |
| |
| // Stupid Java needs a union |
| Object val; |
| |
| // Remember data type when the value is null |
| byte type = DataType.NULL; |
| /** |
| * Adds expression to the plan |
| * @param plan LogicalExpressionPlan this constant is a part of. |
| * @param val Value of this constant. |
| */ |
| public ConstantExpression(OperatorPlan plan, Object val){ |
| super("Constant", plan); |
| this.val = val; |
| plan.add(this); |
| } |
| |
| /** |
| * @link org.apache.pig.newplan.Operator#accept(org.apache.pig.newplan.PlanVisitor) |
| */ |
| @Override |
| public void accept(PlanVisitor v) throws FrontendException { |
| if (!(v instanceof LogicalExpressionVisitor)) { |
| throw new FrontendException("Expected LogicalExpressionVisitor", 2222); |
| } |
| ((LogicalExpressionVisitor)v).visit(this); |
| |
| } |
| |
| /** |
| * Get the value of this constant. |
| * @return value of the constant |
| */ |
| public Object getValue() { |
| return val; |
| } |
| |
| public void setValue(Object val) { |
| this.val = val; |
| } |
| |
| |
| @Override |
| public boolean isEqual(Operator other) throws FrontendException { |
| if (other != null && other instanceof ConstantExpression) { |
| ConstantExpression co = (ConstantExpression)other; |
| return co.getFieldSchema().isEqual(getFieldSchema()) && ( ( co.val == null && val == null ) |
| || ( co != null && co.val.equals(val) ) ); |
| } else { |
| return false; |
| } |
| } |
| |
| @Override |
| public LogicalFieldSchema getFieldSchema() throws FrontendException { |
| if (fieldSchema!=null) |
| return fieldSchema; |
| try { |
| fieldSchema = Util.translateFieldSchema(DataType.determineFieldSchema(val)); |
| }catch (Exception e) { |
| throw new FrontendException( |
| "Error determining field schema from object in constant expression", |
| 1125, |
| PigException.INPUT, |
| e |
| ); |
| } |
| uidOnlyFieldSchema = fieldSchema.mergeUid(uidOnlyFieldSchema); |
| if (type != DataType.NULL && fieldSchema.type == DataType.BYTEARRAY && val == null) { |
| fieldSchema.type = type; |
| } |
| return fieldSchema; |
| } |
| |
| @Override |
| public LogicalExpression deepCopy(LogicalExpressionPlan lgExpPlan) throws FrontendException{ |
| ConstantExpression copy = new ConstantExpression(lgExpPlan, this.getValue()); |
| copy.type = this.type; |
| copy.setLocation( new SourceLocation( location ) ); |
| return copy; |
| } |
| |
| public void inheritSchema(LogicalExpression expr) throws FrontendException { |
| fieldSchema = expr.getFieldSchema(); |
| uidOnlyFieldSchema = fieldSchema.mergeUid(uidOnlyFieldSchema); |
| if (fieldSchema.type != DataType.NULL) { |
| type = fieldSchema.type; |
| } |
| } |
| } |