public function appendService(ServiceBase $successor)
    {
        if ($this->successor !== null) {
            $this->successor->appendService($successor);
        } else {
            $this->successor = $successor;
        }
    }
public function appendService(ServiceBase $successor)
    {
        if ($this->successor !== null) {
            $this->successor->appendService($successor);
        } else {
            $this->successor = $successor;
        }
    }
public function appendService ( ServiceBase $ successor ) { if ( $ this -> successor !== null ) { $ this -> successor -> appendService ( $ successor ) ; } else { $ this -> successor = $ successor ; } }
Append service to chain of responsibility

@param ServiceBase $successor
Append service to chain of responsibility