On 13 June 2013 18:38, David Harkness <david.h@xxxxxxxxxxxxxxxxx> wrote:
> Hi Richard,
>
> On Thu, Jun 13, 2013 at 10:16 AM, Richard Quadling <rquadling@xxxxxxxxx>wrote:
>
>> I'm building a class which needs to have certain methods called by the
>> subclass, but the subclass can extend but not obscure/override the
>> behaviour.
>>
>
> This is the Template Method pattern, though in this case you could use a
> Strategy where the specific authentication implementation is in a separate
> class that gets injected into the Auth class. As for your example there a a
> few things I would change.
>
> * The template method that the subclass must implement should not be
> declared by an interface. Interfaces are for declaring public contracts.
> You can simply declare an abstract, protected method in Auth. This is the
> contract that every subclass must fulfill.
>
> * I would avoid reference variables as you've indicated. If you don't want
> to build a data-holder class yet, simply return an array for now. While you
> cannot enforce the return type at parse time, they should be verified with
> unit tests. Unit tests are critical with dynamic languages like PHP and
> Python since runtime is the only way to verify behavior.
>
> Otherwise, your example is spot on, though the name AuthRequestMade
> implies the request has already been made yet I think from your description
> that this method should *make* the actual request. Here's how I would
> write it with the above in place.
>
> class Auth {
> public function MakeAuthRequest() {
> // before
> $this->MakeAuthRequestImpl(); // Adding "Impl" suffix is a
> common convention
> // after
> }
>
> /**
> * Make the actual authentication request.
> *
> * @return array Must contain keys "state" and "message" to hold
> the result
> */
> protected abstract function MakeAuthRequestImpl();
> }
>
> Peace,
> David
>
>
Excellent advice.
I will be making an extendable data holder class. I'm going to do the sort
of thing Zend_Db does for the adapter/rowset/row classes, allowing an
extended class to supply the corresponding extended adapter/rowset/row
classes. Each of the base classes has a job to do, but they can only
operate in conjunction with an external provider.
Thanks for the pointers.
Richard.
--
Richard Quadling
Twitter : @RQuadling
EE : http://e-e.com/M_248814.html
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