On Oct 16, 10:18 pm, Tim Perrett <[EMAIL PROTECTED]> wrote:
> Ok cool - I think im getting this :)
>
> Somthing else I've just been noodling and I havent tried yet, what
> happens if you repeatably call a method on a case class? I was
> thinking of having something like:
>
> var x = PaypalIPNHandler().onEvent(CompletedPayment, myfunction _ ::
> anotherFunc _ :: Nil).onEvent(PendingPayment, dealWithPending _ ::
> Nil)
That is up to you. Note that a List is immutable so if in you onEvent
function you just assign the reference to the List to you internal
variable then existent list will be overwritten by the list passed on
second call of the onEvent. If you want unicity and list concatenation
for subsequent onEvent calls you have multiple option (with a bit of
coding):
1. Use HashSet
2. Concatenate the current list with the one passed as parameter and
the assign the result of removeDifferences to you variable like:
myList = (myList ::: list).removeDuplicates
3. Play with diff and intersect ... but it is probably the most
expensive
Br's,
Marius
>
> Would the variable X have both event handlers or would it just have
> one? I have a list of event objects to wrap the statuses retrived from
> paypal like so:
>
> val paypalPaymentStatuses: List[PaypalPaymentStatus] = List(
> CanceledPayment,
> ClearedPayment,
> CompletedPayment,
> DeniedPayment,
> ExpiredPayment,
> FailedPayment,
> FailedPayment,
> PendingPayment,
> RefundedPayment,
> ReturnedPayment,
> ReversedPayment,
> UnclaimedPayment,
> UnclearedPayment
> )
>
> and would like to make is easy for the user to setup behavior for
> there individual circumstances.
>
> Cheers
>
> Tim
>
> On Oct 16, 7:43 pm, Marius <[EMAIL PROTECTED]> wrote:
>
> > On Oct 16, 9:33 pm, Tim Perrett <[EMAIL PROTECTED]> wrote:
>
> > > Thanks for the explanation Marius - that makes perfect sense. I'll
> > > take that advice as your right, it fits the need perfectly.
>
> > > If I wanted a list of functions that could have a couple of different
> > > parameters I guess it would be:
>
> > > List[(String,Int) => Any]
>
> > > Or whatever, right?
>
> > Right
>
> > Also, what is the Any for?
>
> > Any is there so you can basically use a function that returns
> > anything, Unit, Int String ... if you just don't care about the
> > function's result.
>
> > Does that define what
>
> > > type of function is valid as a callable function?
>
> > Kind of ...yes ... any function that fits that signature.
>
> > For instance, if i
>
> > > had a trait / class with a bunch of methods in that I wanted the user
> > > to start with, could I do something like:
>
> > > List[(String) => PaypalHandler]
>
> > > so that only methods of type PaypalHandler or subclasses are valid?
>
> > Yes it should due to covariant return types.
>
> > > Cheers
>
> > > Tim
>
> > > On Oct 16, 7:24 pm, Marius <[EMAIL PROTECTED]> wrote:
>
> > > > well List[(String) => Any] is a list of functions that take a String
> > > > as an argument and return an Any
>
> > > > Assume we have two functions that we want tobe called when a failure
> > > > occurs
> > > > def f1(s: String) = ...
>
> > > > def f2(s: Sting) = ...
>
> > > > PaypalIPNHandler().onFailure(f1 _ :: f2 _ :: NIL)
>
> > > > We're passed here a list of partially applied functions. This
> > > > functions will be sequentially called when a failure occurs. Note that
> > > > you can use curried functions as well if you want to pass additional
> > > > state
>
> > > > onFailure is defined something like
>
> > > > def onFailure(funcs: List[(String) => Any]) = failureFuncs = funcs
>
> > > > when a failure occurs you can do
>
> > > > failureFuncs.map(_("failure info")) // for each function registered
> > > > just call it.
>
> > > > Now, again, here I used a String as an argument (lack of inspiration)
> > > > but it can be your own object holding relevant information about your
> > > > failure.
>
> > > > This approach seems to fit your requirements of "I want to build it so
> > > > that users can execute any code they wish upon a different event from
> > > > paypal. " since users can register "arbitrary" functions
>
> > > > Br's,
> > > > Marius
>
> > > > On Oct 16, 4:52 pm, Tim Perrett <[EMAIL PROTECTED]> wrote:
>
> > > > > > Do default handlers actually do anything?
>
> > > > > Right now, no they don't, I need to noodle the design to make sure
> > > > > there's nothing that it would be usefull to inherit
>
> > > > > > Why not using functions or a List[(String) => Any] (Instead of
> > > > > > String
> > > > > > you may pass any type so the function signature is not so
> > > > > > important).
> > > > > > This is a paradigm used in Lift a lot.
>
> > > > > I can't say I'm familiar with that syntax? (well, what it's actually
> > > > > doing). Might you be able to explain a little?
>
> > > > > I want to build it so that users can execute any code they wish upon a
> > > > > different event from paypal.
>
> > > > > Cheers
>
> > > > > Tim
>
> > > > > > Br's,
> > > > > > Marius
>
> > > > > > On Oct 16, 1:36 pm, Tim Perrett <[EMAIL PROTECTED]> wrote:
> > > > > >> Hey guys,
>
> > > > > >> Im just implementing the IPN stuff for paypal and had a quick
> > > > > >> question. I think it would be cool to write something like:
>
> > > > > >> PaypalIPNHandler(
> > > > > >> ).onFailure(FailureHandler).onVerified(VerifiedHandler)
>
> > > > > >> object FailureHandler { ... } // or case class etc
> > > > > >> object VerifiedHandler { ... }
>
> > > > > >> Im thinking of this so that then users can subclass the default
> > > > > >> handlers and get all the functionality / processing that comes as
> > > > > >> default, but then lets them customise so they can update the
> > > > > >> database
> > > > > >> or whatever they want to do with that information.
>
> > > > > >> So, my question is this: is this a good idea? Any drawbacks in
> > > > > >> doing
> > > > > >> this?
>
> > > > > >> Cheers
>
> > > > > >> Tim
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