Java tutorial
/** * 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.apex.malhar.lib.window.accumulation; import org.apache.apex.malhar.lib.window.Accumulation; import org.apache.commons.lang3.mutable.MutableLong; /** * Sum accumulation for longs. * * @since 3.5.0 */ public class SumLong implements Accumulation<Long, MutableLong, Long> { @Override public MutableLong defaultAccumulatedValue() { return new MutableLong(0L); } @Override public MutableLong accumulate(MutableLong accumulatedValue, Long input) { accumulatedValue.add(input); return accumulatedValue; } @Override public MutableLong merge(MutableLong accumulatedValue1, MutableLong accumulatedValue2) { accumulatedValue1.add(accumulatedValue2); return accumulatedValue1; } @Override public Long getOutput(MutableLong accumulatedValue) { return accumulatedValue.longValue(); } @Override public Long getRetraction(Long value) { return -value; } }