001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.commons.functor.aggregator.functions; 018 019import org.apache.commons.functor.BinaryFunction; 020 021/** 022 * Aggregator function to be used with subclasses of 023 * {@link org.apache.commons.functor.aggregator.AbstractNoStoreAggregator} which 024 * sums up the 2 given numbers (hence the "Binary" in the name!). Counterpart of 025 * {@link DoubleSumAggregatorFunction}. 026 */ 027public final class DoubleSumAggregatorBinaryFunction implements BinaryFunction<Double, Double, Double> { 028 /** 029 * Adds the 2 numbers together and returns the result. 030 * 031 * @param left 032 * first number to add. If <code>null</code>, then 033 * <code>right</code> will be returned. 034 * @param right 035 * second number to add. If <code>null</code>, then 036 * <code>left</code> will be returned. 037 * @return sum of the 2 double's as described above 038 */ 039 public Double evaluate(Double left, Double right) { 040 if (left == null) { 041 return right; 042 } 043 if (right == null) { 044 return left; 045 } 046 return left + right; 047 } 048 049 @Override 050 public String toString() { 051 return DoubleSumAggregatorBinaryFunction.class.getName(); 052 } 053}