protected function _setClassName($class, $fallback)
    {
        if (!class_exists($class)) {
            $class = $fallback;
        }
        $this->_className = $class;
        $this->_datetimeInstance = new $this->_className;
    }
protected function _setClassName($class, $fallback)
    {
        if (!class_exists($class)) {
            $class = $fallback;
        }
        $this->_className = $class;
        $this->_datetimeInstance = new $this->_className;
    }
protected function _setClassName ( $ class , $ fallback ) { if ( ! class_exists ( $ class ) ) { $ class = $ fallback ; } $ this -> _className = $ class ; $ this -> _datetimeInstance = new $ this -> _className ; }
Set the classname to use when building objects.

@param string $class The classname to use.
@param string $fallback The classname to use when the preferred class does not exist.
@return void
Set the classname to use when building objects .