/**
    * 
    */
   package org.opentrafficsim.water.statistics;
   
   import java.io.Serializable;
   
   import org.apache.poi.ss.usermodel.Row;
   import org.apache.poi.ss.usermodel.Sheet;
  
  import com.thoughtworks.xstream.annotations.XStreamAlias;
  import com.thoughtworks.xstream.annotations.XStreamOmitField;
  
  /**
   * <br>
   * Copyright (c) 2011-2013 TU Delft, Faculty of TBM, Systems and Simulation <br>
   * This software is licensed without restrictions to Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek TNO
   * (TNO), Erasmus University Rotterdam, Delft University of Technology, Panteia B.V., Stichting Projecten Binnenvaart, Ab Ovo
   * Nederland B.V., Modality Software Solutions B.V., and Rijkswaterstaat - Dienst Water, Verkeer en Leefomgeving, including the
   * right to sub-license sources and derived products to third parties. <br>
   * @version Apr 1, 2013 <br>
   * @author <a href="http://tudelft.nl/averbraeck">Alexander Verbraeck </a>
   */
  @XStreamAlias("counter")
  public class XCounter implements Serializable
  {
      /** */
      @XStreamOmitField
      private static final long serialVersionUID = 1L;
  
      /** count represents the value of the counter. */
      protected long count = Long.MIN_VALUE;
  
      /** n represents the number of measurements. */
      protected long n = Long.MIN_VALUE;
  
      /** description refers to the title of this counter. */
      protected String description;
  
      /** the semaphore. */
      @XStreamOmitField
      private Object semaphore = new Object();
  
      /**
       * constructs a new CounterTest.
       * @param description the description for this counter
       */
      public XCounter(final String description)
      {
          super();
          this.description = description;
      }
  
      /**
       * Returns the current counter value.
       * @return long the counter value
       */
      public long getCount()
      {
          return this.count;
      }
  
      /**
       * Returns the current number of observations.
       * @return long the number of observations
       */
      public long getN()
      {
          return this.n;
      }
  
      /**
       * @param value the value
       */
      public void count(final long value)
      {
          synchronized (this.semaphore)
          {
              this.setCount(this.count + value);
              this.setN(this.n + 1);
          }
      }
  
      /**
       * @see java.lang.Object#toString()
       */
      @Override
      public String toString()
      {
          return this.description;
      }
  
      /**
       * initializes the counter.
       */
      public void initialize()
      {
          synchronized (this.semaphore)
          {
             this.setN(0);
             this.setCount(0);
         }
     }
 
     /**
      * is the counter initialized?
      * @return returns whether the counter is initialized
      */
     public boolean isInitialized()
     {
         return this.n != Long.MIN_VALUE;
     }
 
     /**
      * sets the count.
      * @param count the value
      */
     private void setCount(final long count)
     {
         this.count = count;
     }
 
     /**
      * sets n
      * @param n the number of measurements.
      */
     private void setN(final long n)
     {
         this.n = n;
     }
 
     /**
      * returns the description of the counter.
      * @return String the description
      */
     public String getDescription()
     {
         return this.description;
     }
 
     /**
      * Write statistics to an excel spreadsheet, starting on row "startRow".
      * @param sheet the sheet
      * @param startRow the first row
      * @return first free row after writing
      */
     public int writeToExcel(final Sheet sheet, final int startRow)
     {
         int rownr = startRow;
         Row row = sheet.createRow(rownr);
         row.createCell(1).setCellValue(description);
         row.createCell(2).setCellValue("count [n, telling]");
         row.createCell(3).setCellValue(getN());
         row.createCell(4).setCellValue(getCount());
         return rownr + 1;
     }
 }