| /** |
| * 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.storm.streams.processors; |
| |
| import org.apache.storm.streams.operations.Reducer; |
| |
| public class ReduceProcessor<T> extends BaseProcessor<T> implements BatchProcessor { |
| private final Reducer<T> reducer; |
| private T agg; |
| |
| public ReduceProcessor(Reducer<T> reducer) { |
| this.reducer = reducer; |
| } |
| |
| @Override |
| public void execute(T input) { |
| agg = (agg == null) ? input : reducer.apply(agg, input); |
| mayBeForwardAggUpdate(() -> agg); |
| } |
| |
| @Override |
| public void finish() { |
| if (agg != null) { |
| context.forward(agg); |
| agg = null; |
| } |
| } |
| } |