001/*
002 * SonarQube, open source software quality management tool.
003 * Copyright (C) 2008-2013 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 */
020package org.sonar.api.measures;
021
022import java.util.Collections;
023import java.util.List;
024
025/**
026 * @since 2.0
027 */
028public 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  public List<Metric> dependsUponMetrics() {
042    return Collections.emptyList();
043  }
044
045  public Measure calculate(FormulaData data, FormulaContext context) {
046    double sum=0.0;
047    double count=0.0;
048    boolean hasValue=false;
049
050    for (FormulaData child : data.getChildren()) {
051      Measure measure = child.getMeasure(context.getTargetMetric());
052      Measure weightingMeasure = child.getMeasure(weightingMetric);
053      if (MeasureUtils.haveValues(measure, weightingMeasure)) {
054        sum += measure.getValue() * weightingMeasure.getValue();
055        count += weightingMeasure.getValue();
056        hasValue=true;
057      }
058    }
059
060    if (!hasValue && !zeroIfNoValues) {
061      return null;
062    }
063
064    double result = count==0.0 ? 0.0 : sum/count;
065    return new Measure(context.getTargetMetric(), result);
066  }
067}
068