/*
* 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.piggybank.evaluation.math;
import java.io.IOException;
import java.util.List;
import java.util.ArrayList;
import org.apache.pig.impl.logicalLayer.FrontendException;
import org.apache.pig.FuncSpec;
import org.apache.pig.data.Tuple;
import org.apache.pig.impl.logicalLayer.schema.Schema;
import org.apache.pig.data.DataType;
/**
* base class for math udfs that return Double value
*/
public abstract class DoubleDoubleBase extends Base{
// each derived class provides the computation here
abstract Double compute(Double input1, Double input2);
/**
* java level API
* @param input expects a tuple with a single Double value
* @param output returns a Double value
*/
public Double exec(Tuple input) throws IOException {
if (input == null || input.size() < 2)
return null;
try {
Double val1 = (Double)input.get(0);
Double val2 = (Double)input.get(1);
return (val1 == null || val2 == null) ? null : compute(val1, val2);
} catch (Exception e){
throw new IOException("Caught exception processing input of " + this.getClass().getName(), e);
}
}
/* (non-Javadoc)
* @see org.apache.pig.EvalFunc#getArgToFuncMapping()
*/
@Override
public List<FuncSpec> getArgToFuncMapping() throws FrontendException {
List<FuncSpec> funcList = new ArrayList<FuncSpec>();
List<Schema.FieldSchema> fields = new ArrayList<Schema.FieldSchema>();
fields.add(new Schema.FieldSchema(null, DataType.DOUBLE));
fields.add(new Schema.FieldSchema(null, DataType.DOUBLE));
funcList.add(new FuncSpec(this.getClass().getName(), new Schema(fields)));
return funcList;
}
}