/**
 * 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;
        }
    }
}