001/*
002 * Sonar, open source software quality management tool.
003 * Copyright (C) 2008-2012 SonarSource
004 * mailto:contact AT sonarsource DOT com
005 *
006 * Sonar 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 * Sonar 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
017 * License along with Sonar; if not, write to the Free Software
018 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
019 */
020
021package org.sonar.api.measures;
022
023import org.sonar.api.resources.ResourceUtils;
024
025import java.util.Arrays;
026import java.util.List;
027
028/**
029 * Formula used to compute an average for a given metric A, which is the result of the sum of measures of this metric (A) divided by another metric (B).
030 * <p/>
031 * For example: to compute the metric "complexity by file", the main metric (A) is "complexity" and the other metric (B) is "file".
032 *
033 * @since 3.0
034 */
035public class AverageFormula implements Formula {
036
037  private Metric mainMetric;
038  private Metric byMetric;
039
040  /**
041   * This method should be private but it kep package-protected because of AverageComplexityFormula.
042   */
043  AverageFormula(Metric mainMetric, Metric byMetric) {
044    this.mainMetric = mainMetric;
045    this.byMetric = byMetric;
046  }
047
048  /**
049   * Creates a new {@link AverageFormula} class.
050   *
051   * @param main The metric on which average should be calculated (ex.: "complexity")
052   * @param by   The metric used to divide the main metric to compute average (ex.: "file" for "complexity by file")
053   */
054  public static AverageFormula create(Metric main, Metric by) {
055    return new AverageFormula(main, by);
056  }
057
058  /**
059   * {@inheritDoc}
060   */
061  public List<Metric> dependsUponMetrics() {
062    return Arrays.asList(mainMetric, byMetric);
063  }
064
065  /**
066   * {@inheritDoc}
067   */
068  public Measure calculate(FormulaData data, FormulaContext context) {
069    if (!shouldDecorateResource(data, context)) {
070      return null;
071    }
072
073    Measure result;
074    if (ResourceUtils.isFile(context.getResource())) {
075      result = calculateForFile(data, context);
076    } else {
077      result = calculateOnChildren(data, context);
078    }
079    return result;
080  }
081
082  private Measure calculateOnChildren(FormulaData data, FormulaContext context) {
083    Measure result = null;
084
085    double totalByMeasure = 0;
086    double totalMainMeasure = 0;
087    boolean hasApplicableChildren = false;
088
089    for (FormulaData childrenData : data.getChildren()) {
090      Double childrenByMeasure = MeasureUtils.getValue(childrenData.getMeasure(byMetric), null);
091      Double childrenMainMeasure = MeasureUtils.getValue(childrenData.getMeasure(mainMetric), null);
092      if (childrenMainMeasure != null && childrenByMeasure != null && childrenByMeasure > 0.0) {
093        totalByMeasure += childrenByMeasure;
094        totalMainMeasure += childrenMainMeasure;
095        hasApplicableChildren = true;
096      }
097    }
098    if (hasApplicableChildren) {
099      result = new Measure(context.getTargetMetric(), (totalMainMeasure / totalByMeasure));
100    }
101    return result;
102  }
103
104  private Measure calculateForFile(FormulaData data, FormulaContext context) {
105    Measure result = null;
106
107    Double byMeasure = MeasureUtils.getValue(data.getMeasure(byMetric), null);
108    Double mainMeasure = MeasureUtils.getValue(data.getMeasure(mainMetric), null);
109    if (mainMeasure != null && byMeasure != null && byMeasure > 0.0) {
110      result = new Measure(context.getTargetMetric(), (mainMeasure / byMeasure));
111    }
112
113    return result;
114  }
115
116  private boolean shouldDecorateResource(FormulaData data, FormulaContext context) {
117    return !MeasureUtils.hasValue(data.getMeasure(context.getTargetMetric()));
118  }
119}