package org.lcsim.util.loop;
   
   import hep.io.stdhep.StdhepEvent;
   import hep.io.stdhep.StdhepWriter;
   import java.io.File;
   import java.io.IOException;
   import org.lcsim.event.EventHeader;
   import org.lcsim.util.Driver;
   
  /**
   * A driver for writing out Stdhep events.
   * This driver only works if the event was orignially read in from a stdhep file.
   * The driver writes out the original event, as read from the input file. Thus
   * it is useful for filtering events from stdhep files, but not for modifying
   * events in stdhep files.
   * @author tonyj
   */
  public class StdhepDriver extends Driver
  {
     private StdhepWriter writer;
     private String file;
     private String title;
     private String comment;
     private int expectedEvents;
     
     public StdhepDriver(String file, String title, String comment, int expectedEvents)
     {
        this.file = file;
        this.title = title;
        this.comment = comment;
        this.expectedEvents = expectedEvents;
     }
     protected void startOfData()
     {
        try
        {
           writer = new StdhepWriter(file, title, comment, expectedEvents);
        }
        catch (IOException x)
        {
           throw new RuntimeException("Error opening Stdhep file",x);
        }
     } 
     public StdhepDriver(File file, String title, String comment, int expectedEvents)
     {
        try
        {
           writer = new StdhepWriter(file.getAbsolutePath(), title, comment, expectedEvents);
        }
        catch (IOException x)
        {
           throw new RuntimeException("Error opening Stdhep file",x);
        }
     }  
  
     protected void process(EventHeader event)
     {
        try
        {
           StdhepEvent se = (StdhepEvent) event.get("StdhepEvent");
           writer.writeRecord(se);
        }
        catch (IOException x)
        {
           throw new RuntimeException("Error writing Stdhep file",x);
        }
     }   
  
     protected void endOfData()
     {
        try
        {
           if (writer != null)
           {
              writer.close();
              writer = null;
           }
        }
        catch (IOException x)
        {
           throw new RuntimeException("Error closing Stdhep file",x);
        }
     }
     
     protected void suspend()
     {
  // We can't do this yet, the flush method is not in the current version of stdhep/MCFIO
  //      try
  //      {
  //         writer.flush();
  //      }
  //      catch (IOException x)
  //      {
  //         throw new RuntimeException("Error flushing Stdhep file",x);
  //      }
     }
  }