/**
    * 
    */
   package org.opentrafficsim.water.statistics;
   
   import java.io.Serializable;
   import java.util.SortedMap;
   import java.util.TreeMap;
   
  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 Mar 24, 2013 <br>
   * @author <a href="http://tudelft.nl/averbraeck">Alexander Verbraeck </a>
   */
  @XStreamAlias("frequency")
  public class XFrequency implements Serializable
  {
      /** */
      @XStreamOmitField
      private static final long serialVersionUID = 1L;
  
      /** count represents the values of the counters */
      protected SortedMap<String, Long> frequency = new TreeMap<String, Long>();
  
      /** 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();
  
      /**
       * @param description the description of the statistic
       */
      public XFrequency(String description)
      {
          super();
          this.description = description;
      }
  
      /**
       * Returns the current counter value for a key
       * 
       * @param key the string key for the counter
       * @return long the counter value
       */
      public long getFrequency(final String key)
      {
          return this.frequency.get(key);
      }
  
      /**
       * Returns all counters
       * 
       * @return the counter values
       */
      public SortedMap<String, Long> getFrequencies()
      {
          return this.frequency;
      }
  
      /**
       * Returns the current number of observations
       * 
       * @return long the number of observations
       */
      public long getN()
      {
          return this.n;
      }
  
      /**
       * count frequency
       * 
       * @param key the key to count the value under
       * @param value the value
       */
      public void count(final String key, final long value)
      {
          synchronized (this.semaphore)
          {
              if (!this.frequency.containsKey(key))
                  this.frequency.put(key, value);
              else
                 this.frequency.put(key, this.frequency.get(key) + value);
             this.setN(this.n + 1);
         }
     }
 
     /**
      * count 1
      * 
      * @param key key
      */
     public void count(final String key)
     {
         this.count(key, 1L);
     }
 
     /**
      * @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.frequency.clear();
         }
     }
 
     /**
      * is the counter initialized?
      * 
      * @return returns whether the counter is initialized
      */
     public boolean isInitialized()
     {
         return this.n != Long.MIN_VALUE;
     }
 
     /**
      * 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 excel sheet to write to 
      * @param startRow the first row of writing
      * @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("naam");
         row.createCell(3).setCellValue("frequentie");
         for (String key : frequency.keySet())
         {
             rownr++;
             row = sheet.createRow(rownr);
             row.createCell(2).setCellValue(key);
             row.createCell(3).setCellValue(frequency.get(key));
         }
         return rownr + 1;
     }
 
 }