001    /*--------------------------------------------------------------------------+
002    $Id: SumAggregator.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    /**
021     * Sum aggregator.
022     * 
023     * @author deissenb
024     * @author $Author: hummelb $
025     * @version $Rev: 28099 $
026     * @levd.rating GREEN Hash: 2BC7AD863CFA78522BE30785E9043E5F
027     */
028    public class SumAggregator extends PairwiseAggregatorBase {
029    
030            /** Returns zero. */
031            @Override
032            public double getNeutralElement() {
033                    return 0;
034            }
035    
036            /** {@inheritDoc} */
037            @Override
038            protected double aggregate(double aggregate, double value) {
039                    return aggregate + value;
040            }
041    }