private String tokenClass(String string){
  if (string == null) {
    return null;
  }
 else   if (string.startsWith("http://")) {
    return "#UrL#";
  }
 else   if (isNumberAndPunctuation(string)) {
    return "#0#";
  }
  return string;
}

private String tokenClass ( String string ) { if ( string == null ) { return null ; } else if ( string . startsWith ( "http://" ) ) { return "#UrL#" ; } else if ( isNumberAndPunctuation ( string ) ) { return "#0#" ; } return string ; }
returns an equivalence class for an input string .
