code: /**
   * Copyright (c) 2004-2005, Regents of the University of California
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * Redistributions of source code must retain the above copyright notice,
   * this list of conditions and the following disclaimer.
   *
   * Redistributions in binary form must reproduce the above copyright
   * notice, this list of conditions and the following disclaimer in the
   * documentation and/or other materials provided with the distribution.
   *
   * Neither the name of the University of California, Los Angeles nor the
   * names of its contributors may be used to endorse or promote products
   * derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  package cck.stat;
  
  import cck.text.Printer;
  
  
  /**
   * This models the min, max, mean, accumulation, total, and number of occurrences of min and max in a stream
   * of integers.
   *
   * @author Ben L. Titzer
   */
  public class MinMaxMean implements DataItem {
      protected final String name;
  
      public float mean;
      public int observedMaximum;
      public int observedMinimum;
      public int countMinimum;
      public int countMaximum;
      public int total;
      public int accumulation;
      protected boolean someData;
      protected String totalname; // name to report for total field
      protected String cumulname; // name to report for cumul field
  
      /**
       * Public constructor initializes the statistics for a sequence of integers.
       */
      public MinMaxMean(String newname) {
          name = newname;
          totalname = "Total";
          cumulname = "Accumulation";
          someData = false;
      }
  
      /**
       * Public constructor initializes the statistics for a sequence of integers.
       */
      public MinMaxMean(String newname, String tn, String cn) {
          name = newname;
          totalname = tn;
          cumulname = cn;
          someData = false;
      }
  
      public String getName() {
          return name;
      }
  
      /**
       * Update the statistical data for the next input value.
       */
      public void record(int value) {
  
          if (!someData) {
              observedMinimum = observedMaximum = value;
              countMinimum = countMaximum = 1;
              mean = value;
              accumulation = value;
              someData = true;
              total = 1;
              return;
          }
  
          if (value > observedMaximum) {
              observedMaximum = value;
              countMaximum = 1;
          } else if (value == observedMaximum) countMaximum++;
  
          if (value < observedMinimum) {
              observedMinimum = value;
              countMinimum = 1;
          } else if (value == observedMinimum) countMinimum++;
  
          accumulation += value;
          total++;
      }
  
      /**
       * process the data so far and update internal statistics.
       */
      public void process() {
          mean = ((float) accumulation) / ((float) total);
      }
  
      /**
       * Generate a textual report of the data gathered.
       * @param printer
       */
      public void print(Printer printer) {
          printer.print("\n " + name);
          printer.print("\n---------------------------------------------------------------------\n");
  
          if (totalname != null) {
              printer.print("   " + totalname + ": " + total);
          }
          if (cumulname != null) {
              printer.print("   " + cumulname + ": " + accumulation);
          }
  
          printer.print("\n Statistics: ");
          printer.print("\n   Minimum: " + observedMinimum + ", " + countMinimum + " occurences of min.");
          printer.print("\n   Maximum: " + observedMaximum + ", " + countMaximum + " occurences of max.");
          printer.print("\n   Mean: " + mean + '\n');
      }
  
      /**
       * Merge the results of two MinMaxMean objects into one.
       */
      public MinMaxMean merge(MinMaxMean m) {
          MinMaxMean result = new MinMaxMean(name);
  
          if (m.observedMaximum > observedMaximum) {
              result.observedMaximum = m.observedMaximum;
              result.countMaximum = m.countMaximum;
          } else if (m.observedMaximum == observedMaximum) {
              result.observedMaximum = observedMaximum;
              result.countMaximum = countMaximum + m.countMaximum;
          } else {
              result.observedMaximum = observedMaximum;
              result.countMaximum = countMaximum;
          }
  
          if (m.observedMinimum < observedMinimum) {
              result.observedMinimum = m.observedMinimum;
              result.countMinimum = m.countMinimum;
          } else if (m.observedMinimum == observedMinimum) {
              result.observedMinimum = observedMinimum;
              result.countMinimum = countMinimum + m.countMinimum;
          } else {
              result.observedMinimum = observedMinimum;
              result.countMinimum = countMinimum;
          }
  
          result.total = total + m.total;
          result.accumulation = accumulation + m.accumulation;
          result.mean = ((m.mean * m.total) + (mean * total)) / result.total;
          return result;
      }
  
      public boolean empty() {
          return !someData;
      }
  
      public String toString() {
          return name;
      }
  }
  