/*
* 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.builtin;
import java.io.IOException;
import java.util.Iterator;
import org.apache.pig.Accumulator;
import org.apache.pig.Algebraic;
import org.apache.pig.EvalFunc;
import org.apache.pig.PigException;
import org.apache.pig.backend.executionengine.ExecException;
import org.apache.pig.data.DataBag;
import org.apache.pig.data.DataType;
import org.apache.pig.data.Tuple;
import org.apache.pig.data.TupleFactory;
import org.apache.pig.impl.logicalLayer.schema.Schema;
/**
* This method should never be used directly, use {@link SUM}.
*/
public class FloatSum extends EvalFunc<Double> implements Algebraic, Accumulator<Double>{
@Override
public Double exec(Tuple input) throws IOException {
try {
return sum(input);
} catch (ExecException ee) {
throw ee;
} catch (Exception e) {
int errCode = 2106;
String msg = "Error while computing sum in " + this.getClass().getSimpleName();
throw new ExecException(msg, errCode, PigException.BUG, e);
}
}
public String getInitial() {
return Initial.class.getName();
}
public String getIntermed() {
return Intermediate.class.getName();
}
public String getFinal() {
return Final.class.getName();
}
static public class Initial extends EvalFunc<Tuple> {
private static TupleFactory tfact = TupleFactory.getInstance();
@Override
public Tuple exec(Tuple input) throws IOException {
// Initial is called in the map - for SUM
// we just send the tuple down
try {
// input is a bag with one tuple containing
// the column we are trying to sum
DataBag bg = (DataBag) input.get(0);
Float f = null;
if(bg.iterator().hasNext()) {
Tuple tp = bg.iterator().next();
f = (Float)tp.get(0);
}
// send down a double since intermediate
// would be sending a double
return tfact.newTuple(f != null ?
new Double(f) : null);
} catch (ExecException e) {
throw e;
} catch (Exception e) {
int errCode = 2106;
String msg = "Error while computing sum in " + this.getClass().getSimpleName();
throw new ExecException(msg, errCode, PigException.BUG, e);
}
}
}
static public class Intermediate extends EvalFunc<Tuple> {
private static TupleFactory tfact = TupleFactory.getInstance();
@Override
public Tuple exec(Tuple input) throws IOException {
try {
return tfact.newTuple(sumDoubles(input));
} catch (ExecException ee) {
throw ee;
} catch (Exception e) {
int errCode = 2106;
String msg = "Error while computing sum in " + this.getClass().getSimpleName();
throw new ExecException(msg, errCode, PigException.BUG, e);
}
}
}
static public class Final extends EvalFunc<Double> {
@Override
public Double exec(Tuple input) throws IOException {
try {
return sumDoubles(input);
} catch (ExecException ee) {
throw ee;
} catch (Exception e) {
int errCode = 2106;
String msg = "Error while computing sum in " + this.getClass().getSimpleName();
throw new ExecException(msg, errCode, PigException.BUG, e);
}
}
}
static protected Double sumDoubles(Tuple input) throws ExecException {
// Can't just call sum, because the intermediate results are
// now Doubles insteads of Floats.
DataBag values = (DataBag)input.get(0);
// if we were handed an empty bag, return NULL
// this is in compliance with SQL standard
if(values.size() == 0) {
return null;
}
double sum = 0;
boolean sawNonNull = false;
for (Iterator<Tuple> it = values.iterator(); it.hasNext();) {
Tuple t = it.next();
try {
Double d = (Double)(t.get(0));
if (d == null) continue;
sawNonNull = true;
sum += d;
}catch(RuntimeException exp) {
ExecException newE = new ExecException("Error processing: " +
t.toString() + exp.getMessage(), exp);
throw newE;
}
}
if(sawNonNull) {
return new Double(sum);
} else {
return null;
}
}
static protected Double sum(Tuple input) throws ExecException {
DataBag values = (DataBag)input.get(0);
// if we were handed an empty bag, return NULL
// this is in compliance with SQL standard
if(values.size() == 0) {
return null;
}
double sum = 0.0;
boolean sawNonNull = false;
for (Iterator<Tuple> it = values.iterator(); it.hasNext();) {
Tuple t = it.next();
try {
Float f = (Float)(t.get(0));
if (f == null) continue;
sawNonNull = true;
sum += f;
}catch(RuntimeException exp) {
int errCode = 2103;
String msg = "Problem while computing sum of floats.";
throw new ExecException(msg, errCode, PigException.BUG, exp);
}
}
if(sawNonNull) {
return new Double(sum);
} else {
return null;
}
}
@Override
public Schema outputSchema(Schema input) {
return new Schema(new Schema.FieldSchema(null, DataType.DOUBLE));
}
/* Accumulator interface implementation*/
private Double intermediateSum = null;
@Override
public void accumulate(Tuple b) throws IOException {
try {
Double curSum = sum(b);
if (curSum == null) {
return;
}
intermediateSum = (intermediateSum == null ? 0.0 : intermediateSum) + curSum;
} catch (ExecException ee) {
throw ee;
} catch (Exception e) {
int errCode = 2106;
String msg = "Error while computing min in " + this.getClass().getSimpleName();
throw new ExecException(msg, errCode, PigException.BUG, e);
}
}
@Override
public void cleanup() {
intermediateSum = null;
}
@Override
public Double getValue() {
return intermediateSum;
}
}