001    /*
002     * SonarQube, open source software quality management tool.
003     * Copyright (C) 2008-2014 SonarSource
004     * mailto:contact AT sonarsource DOT com
005     *
006     * SonarQube is free software; you can redistribute it and/or
007     * modify it under the terms of the GNU Lesser General Public
008     * License as published by the Free Software Foundation; either
009     * version 3 of the License, or (at your option) any later version.
010     *
011     * SonarQube is distributed in the hope that it will be useful,
012     * but WITHOUT ANY WARRANTY; without even the implied warranty of
013     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014     * Lesser General Public License for more details.
015     *
016     * You should have received a copy of the GNU Lesser General Public License
017     * along with this program; if not, write to the Free Software Foundation,
018     * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
019     */
020    package org.sonar.api.measures;
021    
022    import java.util.Collections;
023    import java.util.List;
024    
025    /**
026     * @since 2.0
027     */
028    public class WeightedMeanAggregationFormula implements Formula {
029    
030      private Metric weightingMetric;
031      private boolean zeroIfNoValues=false;
032    
033      public WeightedMeanAggregationFormula(Metric weightingMetric, boolean zeroIfNoValues) {
034        this.weightingMetric = weightingMetric;
035        if (weightingMetric==null) {
036          throw new IllegalArgumentException("Metric can not be null");
037        }
038        this.zeroIfNoValues = zeroIfNoValues;
039      }
040    
041      @Override
042      public List<Metric> dependsUponMetrics() {
043        return Collections.emptyList();
044      }
045    
046      @Override
047      public Measure calculate(FormulaData data, FormulaContext context) {
048        double sum=0.0;
049        double count=0.0;
050        boolean hasValue=false;
051    
052        for (FormulaData child : data.getChildren()) {
053          Measure measure = child.getMeasure(context.getTargetMetric());
054          Measure weightingMeasure = child.getMeasure(weightingMetric);
055          if (MeasureUtils.haveValues(measure, weightingMeasure)) {
056            sum += measure.getValue() * weightingMeasure.getValue();
057            count += weightingMeasure.getValue();
058            hasValue=true;
059          }
060        }
061    
062        if (!hasValue && !zeroIfNoValues) {
063          return null;
064        }
065    
066        double result = Double.doubleToRawLongBits(count)==0L ? 0.0 : sum/count;
067        return new Measure(context.getTargetMetric(), result);
068      }
069    }
070