/*
*
* Copyright © 2010, 2011 Inadco, Inc. All rights reserved.
*
* Licensed 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 com.inadco.hbl.piggybank;
import java.io.IOException;
import java.lang.reflect.Type;
import org.apache.commons.lang.Validate;
import org.apache.pig.PigException;
import org.apache.pig.data.DataByteArray;
import org.apache.pig.data.Tuple;
import com.inadco.hbl.api.AggregateFunctionRegistry;
import com.inadco.hbl.api.Measure;
import com.inadco.hbl.model.SimpleAggregateFunctionRegistry;
import com.inadco.hbl.protocodegen.Cells.Aggregation;
/**
*
* Pig function that takes the measure value, and uses measure to translate it
* to double first and then {@link SimpleAggregateFunctionRegistry} to produce
* final {@link Aggregation}.
* <P>
*
* meausure name and model must be configured thru Pig's DEFINE.
* <P>
*
* The result is byte array containing serialized {@link Aggregation} measure.
*
* @author dmitriy
*
*/
public class AggregationFromMeasure extends BaseFunc<DataByteArray> {
private AggregateFunctionRegistry afr;
private String measureName;
public AggregationFromMeasure(String measureName, String encodedModel) throws PigException {
super(encodedModel);
this.measureName = measureName;
this.afr = super.cube.getAggregateFunctionRegistry();
}
@Override
public DataByteArray exec(Tuple input) throws IOException {
Object measureKey = input.get(0);
Measure m = measureKey == null ? null : cube.getMeasures().get(measureName);
Validate.notNull(m, "no measure passed/found");
Object d = m.compiler2Fact(input.get(1));
// we don't measures to evaluate to nulls to simplify null issues .
if (d == null)
return null;
Aggregation.Builder aggrb = Aggregation.newBuilder();
afr.applyAll(aggrb, d);
return new DataByteArray(aggrb.build().toByteArray());
}
@Override
public Type getReturnType() {
return DataByteArray.class;
}
}