public class  Comm
{
  public CommListener parent;

  public void set(CommListener parent)
    {
      this.parent = parent;
    }
 
  public void start()
    {
     if(parent != null){
       parent.start();
     }
    }
  public void end()
    {
      if(parent !=null){
        parent.end();
      }
    }
  
  public void output(String s)
    {
      if(parent !=null){
        parent.output(s);
      }
    }
  
  public void input(String s)
    {
      if(parent !=null){
        parent.input(s);
      }
    }
  
}