/*
* 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.EvalFunc;
import org.apache.pig.PigException;
import org.apache.pig.backend.executionengine.ExecException;
import org.apache.pig.data.DataBag;
import org.apache.pig.data.DataByteArray;
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;
/**
* Core logic for applying an accumulative/algebraic math function to a
* bag of doubles.
*/
public abstract class AlgebraicByteArrayMathBase extends AlgebraicMathBase<Double> implements Accumulator<Double> {
protected static Double getSeed(KNOWN_OP op) {
switch (op) {
case SUM: return 0.0;
case MIN: return Double.POSITIVE_INFINITY;
case MAX: return Double.NEGATIVE_INFINITY;
default: return null;
}
}
private static Double doWork(Double arg1, Double arg2, KNOWN_OP op) {
if (arg1 == null) {
return arg2;
} else if (arg2 == null) {
return arg1;
} else {
switch (op) {
case MAX: return Math.max(arg1, arg2);
case MIN: return Math.min(arg1, arg2);
case SUM: return arg1 + arg2;
default: return null;
}
}
}
protected static Double doTupleWork(Tuple input, KnownOpProvider opProvider, byte expectedType)
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 sofar = AlgebraicByteArrayMathBase.getSeed(opProvider.getOp());
boolean sawNonNull = false;
for (Iterator<Tuple> it = values.iterator(); it.hasNext();) {
Tuple t = it.next();
try {
Double d;
switch (expectedType) {
case DataType.BYTEARRAY:
DataByteArray dba = (DataByteArray)t.get(0);
d = dba != null ? Double.valueOf(dba.toString()): null;
break;
case DataType.DOUBLE:
d = (Double) t.get(0);
break;
default:
throw new ExecException("Unexpected type in AlgebraicByteArrayMath "
+ DataType.findTypeName(expectedType));
}
if (d == null) continue;
sawNonNull = true;
sofar = doWork(sofar, d, opProvider.getOp());
}catch(RuntimeException exp) {
int errCode = 2103;
throw new ExecException("Problem doing work on Doubles", errCode, PigException.BUG, exp);
}
}
return sawNonNull ? sofar : null;
}
@Override
public Double exec(Tuple input) throws IOException {
try {
return doTupleWork(input, opProvider, DataType.BYTEARRAY);
} catch (ExecException ee) {
throw ee;
} catch (Exception e) {
int errCode = 2106;
throw new ExecException("Error executing function on Doubles", errCode, PigException.BUG, e);
}
}
static public abstract class Intermediate extends AlgebraicMathBase.Intermediate {
private static TupleFactory tfact = TupleFactory.getInstance();
@Override
public Tuple exec(Tuple input) throws IOException {
try {
return tfact.newTuple(doTupleWork(input, this, DataType.DOUBLE));
} catch (ExecException ee) {
throw ee;
} catch (Exception e) {
int errCode = 2106;
throw new ExecException("Error executing function on Doubles", errCode, PigException.BUG, e);
}
}
}
@Override
public String getInitial() {
return Initial.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.
// we just send the tuple down
try {
// input is a bag with one tuple containing
// the column we are trying to operate on
DataBag bg = (DataBag) input.get(0);
if (bg.iterator().hasNext()) {
DataByteArray dba = (DataByteArray) bg.iterator().next().get(0);
Double d = dba != null ? Double.valueOf(dba.toString()): null;
return tfact.newTuple(d);
} else {
// make sure that we call the object constructor, not the list constructor
return tfact.newTuple((Object) null);
}
} catch (ExecException e) {
throw e;
} catch (Exception e) {
int errCode = 2106;
throw new ExecException("Error executing an algebraic function", errCode, PigException.BUG, e);
}
}
}
static public abstract class Final extends AlgebraicMathBase.Final<Double> {
@Override
public Double exec(Tuple input) throws IOException {
try {
return doTupleWork(input, this, DataType.DOUBLE);
} catch (ExecException ee) {
throw ee;
} catch (Exception e) {
int errCode = 2106;
throw new ExecException("Error executing function on Doubles", errCode, PigException.BUG, e);
}
}
}
@Override
public Schema outputSchema(Schema input) {
return new Schema(new Schema.FieldSchema(null, DataType.DOUBLE));
}
/* Accumulator interface implementation*/
private Double intermediateVal = null;
@Override
public void accumulate(Tuple b) throws IOException {
try {
Double curVal = doTupleWork(b, opProvider, DataType.BYTEARRAY);
if (curVal == null) {
return;
}
if (intermediateVal == null) {
intermediateVal = getSeed(opProvider.getOp());
}
intermediateVal = doWork(intermediateVal, curVal, opProvider.getOp());
} catch (ExecException ee) {
throw ee;
} catch (Exception e) {
int errCode = 2106;
throw new ExecException("Error executing function on Doubles", errCode, PigException.BUG, e);
}
}
@Override
public void cleanup() {
intermediateVal = null;
}
@Override
public Double getValue() {
return intermediateVal;
}
}