001 /*--------------------------------------------------------------------------+ 002 $Id: PairwiseAggregatorBase.java 28099 2010-06-09 13:17:22Z hummelb $ 003 | | 004 | Copyright 2005-2010 Technische Universitaet Muenchen | 005 | | 006 | Licensed under the Apache License, Version 2.0 (the "License"); | 007 | you may not use this file except in compliance with the License. | 008 | You may obtain a copy of the License at | 009 | | 010 | http://www.apache.org/licenses/LICENSE-2.0 | 011 | | 012 | Unless required by applicable law or agreed to in writing, software | 013 | distributed under the License is distributed on an "AS IS" BASIS, | 014 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | 015 | See the License for the specific language governing permissions and | 016 | limitations under the License. | 017 +--------------------------------------------------------------------------*/ 018 package edu.tum.cs.commons.math; 019 020 import java.util.Collection; 021 022 /** 023 * This is a base class for aggregators that have a defined neutral element and 024 * operate in pairwise manner. 025 * 026 * @author Florian Deissenboeck 027 * @author $Author: hummelb $ 028 * @version $Rev: 28099 $ 029 * @levd.rating GREEN Hash: B262E418EFDA28F4B7634AA5FDDFD68E 030 */ 031 public abstract class PairwiseAggregatorBase implements IAggregator { 032 033 /** {@inheritDoc} */ 034 @Override 035 public double aggregate(Collection<? extends Number> values) { 036 double result = getNeutralElement(); 037 for (Number value : values) { 038 result = aggregate(result, value.doubleValue()); 039 } 040 return result; 041 } 042 043 /** 044 * Calculate aggregate of two values. 045 * 046 * @param aggregate 047 * the value that has been aggregated by previous pairwise 048 * aggregations 049 * @param value 050 * the new value 051 */ 052 protected abstract double aggregate(double aggregate, double value); 053 }