TimedAverage.java

/*
 * $Id$
 *
 * Copyright 2006, The jCoderZ.org Project. All rights reserved.
 *
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 * modification, are permitted provided that the following conditions are
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 *
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 *      notice, this list of conditions and the following disclaimer.
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 *      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 jCoderZ.org Project nor the names of
 *      its contributors may be used to endorse or promote products
 *      derived from this software without specific prior written
 *      permission.
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 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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
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package org.jcoderz.commons.statistics;

import java.text.DecimalFormat;

import org.jcoderz.commons.types.Date;



/**
 * This is an {@link org.jcoderz.commons.statistics.Average} version that
 * also counts time and can thus compute a frequency (i.e. occurences per
 * time).
 * @author Albrecht Messner
 */
public class TimedAverage
   extends Average
{
   private long mStartTime;
   private long mStopTime;

   /**
    * Constructor.
    * @param name The name of the TimedAverage
    */
   public TimedAverage (String name)
   {
      super(name);
      mStartTime = 0;
      mStopTime = 0;
   }

   /** {@inheritDoc} */
   public synchronized void reset ()
   {
      super.reset();
      mStopTime = 0;
      start();
   }

   /**
    * Starts the timer of this Average.
    */
   public synchronized void start ()
   {
      mStartTime = System.currentTimeMillis();
   }

   /**
    * Stops the timer of this Average.
    */
   public synchronized void stop ()
   {
      mStopTime = System.currentTimeMillis();
   }

   /**
    * Returns the amount of time this Average was running.
    * @return the amount of time this Average was running
    */
   public synchronized long getDuration ()
   {
      long duration;
      if (mStopTime != 0)
      {
         duration = mStopTime - mStartTime;
      }
      else
      {
         duration = System.currentTimeMillis() - mStartTime;
      }
      return duration;
   }

   /**
    * Returns the frequency of this average, i.e. getCount() / duration.
    * @return the frequency of this average, i.e. getCount() / duration.
    */
   public synchronized double getFrequency ()
   {
      final long duration = getDuration();
      final double durationInSec = duration / (double) Date.MILLIS_PER_SECOND;
      double result = 0;
      if (durationInSec > 0)
      {
         result = getCount() / durationInSec;
      }
      return result;
   }

   /** {@inheritDoc} */
   public String toString ()
   {
      final DecimalFormat df = new DecimalFormat("0.000");
      final StringBuffer sbuf = new StringBuffer();
      sbuf.append("[TimedAverage name=").append(getName());
      sbuf.append(", duration=").append(getDuration());
      sbuf.append(", count=").append(getCount());
      sbuf.append(", min=").append(getMinimum());
      sbuf.append(", avg=").append(getAverage());
      sbuf.append(", max=").append(getMaximum());
      sbuf.append(", freq=").append(df.format(getFrequency()));
      sbuf.append(']');
      return sbuf.toString();
   }
}