code: public static int compare( String s1, String s2)
  	{
  		if (s1 == null && s2 == null)
  		{
  			return 0;
  		}
  		else if (s1 == null && s2 != null)
  		{
  			return -1;
  		}
  		else if (s1 != null && s2 == null)
  		{
  			return 1;
  		}
  		else
  		{
  			return s1.compareTo(s2);
  		}
  	}
docs: <p>compare.</p>
  
  @param s1 a {@link java.lang.String} object.
  @param s2 a {@link java.lang.String} object.
  @return a int.