/**
* 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.hadoop.hive.ql.udf;
import org.apache.hadoop.hive.ql.exec.NumericUDAF;
import org.apache.hadoop.hive.ql.exec.UDAFEvaluator;
import org.apache.hadoop.hive.serde2.io.DoubleWritable;
public class UDAFSum extends NumericUDAF {
public static class UDAFSumEvaluator implements UDAFEvaluator {
private double mSum;
private boolean mEmpty;
public UDAFSumEvaluator() {
super();
init();
}
public void init() {
mSum = 0;
mEmpty = true;
}
public boolean iterate(DoubleWritable o) {
if (o != null) {
mSum += o.get();
mEmpty = false;
}
return true;
}
public DoubleWritable terminatePartial() {
// This is SQL standard - sum of zero items should be null.
return mEmpty ? null : new DoubleWritable(mSum);
}
public boolean merge(DoubleWritable o) {
if (o != null) {
mSum += o.get();
mEmpty = false;
}
return true;
}
public DoubleWritable terminate() {
// This is SQL standard - sum of zero items should be null.
return mEmpty ? null : new DoubleWritable(mSum);
}
}
}