/**
  * Clear data from the query or a specific clause of the query.
  *
  * @param   string  $clause  Optionally, the name of the clause to clear, or nothing to clear the whole query.
  *
  * @return  JDatabaseQuery  Returns this object to allow chaining.
  *
  * @since   12.1
  */
 public function clear($clause = null)
 {
     switch ($clause) {
         case null:
             $this->bounded = array();
             break;
     }
     parent::clear($clause);
     return $this;
 }