/**
* 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 storm.trident.operation;
import java.io.Serializable;
import storm.trident.tuple.TridentTuple;
// doesn't manipulate tuples (lists of stuff) so that things like aggregating into
// cassandra is cleaner (don't need lists everywhere, just store the single value there)
public interface CombinerAggregator<T> extends Serializable {
T init(TridentTuple tuple);
T combine(T val1, T val2);
T zero();
}