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 */
020package org.sonar.api.measures;
021
022import java.util.Collection;
023import java.util.Collections;
024import java.util.List;
025
026/**
027 * @since 2.0
028 */
029public class MeanAggregationFormula implements Formula {
030
031  private boolean forceZeroIfMissingData=false;
032
033  public MeanAggregationFormula(boolean forceZeroIfMissingData) {
034    this.forceZeroIfMissingData = forceZeroIfMissingData;
035  }
036
037  public MeanAggregationFormula() {
038    this(false);
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    int count=0;
048    boolean hasValue=false;
049    Collection<Measure> measures = data.getChildrenMeasures(context.getTargetMetric());
050    for (Measure measure : measures) {
051      if (MeasureUtils.hasValue(measure)) {
052        sum+=measure.getValue();
053        count++;
054        hasValue=true;
055      }
056    }
057
058    if (!hasValue && !forceZeroIfMissingData) {
059      return null;
060    }
061    return new Measure(context.getTargetMetric(), (count==0 ? 0.0 : sum/count));
062  }
063}