package org.apache.helix.alerts;
/*
* 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.
*/
import org.apache.helix.HelixException;
public class AccumulateAggregator extends Aggregator {
public AccumulateAggregator()
{
_numArgs = 0;
}
@Override
public void merge(Tuple<String> currValTup, Tuple<String> newValTup,
Tuple<String> currTimeTup, Tuple<String> newTimeTup, String... args) {
double currVal = 0;
double currTime = -1;
double newVal;
double newTime;
double mergedVal;
double mergedTime;
if (currValTup == null || newValTup == null || currTimeTup == null ||
newTimeTup == null) {
throw new HelixException("Tuples cannot be null");
}
//old tuples may be empty, indicating no value/time exist
if (currValTup.size() > 0 && currTimeTup.size() > 0) {
currVal = Double.parseDouble(currValTup.iterator().next());
currTime = Double.parseDouble(currTimeTup.iterator().next());
}
newVal = Double.parseDouble(newValTup.iterator().next());
newTime = Double.parseDouble(newTimeTup.iterator().next());
if (newTime > currTime) { //if old doesn't exist, we end up here
mergedVal = currVal+newVal; //if old doesn't exist, it has value "0"
mergedTime = newTime;
}
else {
mergedVal = currVal;
mergedTime = currTime;
}
currValTup.clear();
currValTup.add(Double.toString(mergedVal));
currTimeTup.clear();
currTimeTup.add(Double.toString(mergedTime));
}
}