ack! hit send before completing that thought!
user = getTransfer.new("user.User");
variables.beaner.populate(user,userData);
result = createResult();
result.setErrors(user.validate("save)) // validate() returns an error
collection struct
If (result.getSuccess()) { // returns true is StructCount(errors) eq 0
getTransfer.save(user);
result.setPayload(getUser(someUniqueIdentifier))
}
return result;
Client code would be
result = UserService.save(userData);
If (result.getSuccess) {
// do somethings with user
} else {
//do something with error collection
}
It would be preferable to me to not have to query the UserService for the
user I just saved.
On Jan 15, 2008 12:53 PM, Paul Marcotte <[EMAIL PROTECTED]> wrote:
> Baz, you're my brother from another mother.
>
> I want to implement a Result object as well, but I'd like it to have a
> "Payload", or some other implementation that reduces an operation to a
> single service call. Here's an example of how the save() method would roll
> in my UserService (using transfer).
>
> user = getTransfer.new("user.User");
> variables.beaner.populate(user,userData);
> result = createResult();
> result.setErrors(user.validate("save)) // validate() returns an error
> collection struct
>
> if (result.getSuccess()) { // returns true is StructCount(errors) eq
> 0getTransfer.save(user);
> }
> else {
> result.addErrorMessages (user.getErrorMessages());
> result.setOriginalData(userData);
> }
> return result;
>
> On Jan 15, 2008 12:16 PM, Baz <[EMAIL PROTECTED]> wrote:
>
> > This is exactly where I wanted the conversation to go!
> >
> > So Peter - if you did have a flex app, and you wanted to save a user
> > what would you do? At minimum you would have to pass in a struct of user
> > values to some webservice - but then what? Would you validate in that
> > method? Or would you have your flex controller first call a validate()
> > webservice method, then depending on the results the save() webservice
> > method?
> >
> > Brian I see you handle the inherent problem by having a custom RESULT
> > structure that you return - I understand why you do this - cuz I do it too -
> > but doesn't it kinda suck? When do you stop using it? At one point I was
> > thinking that I should use it as a return for any service function. The
> > object would have properties like: Status, MessageCode, Payload. This would
> > let me handle almost any cases and keep a standard interface to interact
> > with.
> >
> > Baz
> >
> >
> >
> > On Jan 15, 2008 11:15 AM, Peter Bell <[EMAIL PROTECTED] > wrote:
> >
> > > Hi Brian,
> > >
> > > I'll disagree with you here. The calling code has to know three
> > > things:
> > >
> > > - How to pass information to the service in the format it wants
> > > - How to tell whether the save succeeded
> > > - How to pass any error messages in a way the display will want
> > > to see them (actually, it'll probably just be a conduit for the
> > > information,
> > > so it is more likely the view will have to know this).
> > >
> > >
> > > It needs to know how to pass well formed data to the service otherwise
> > > the save won't work. It needs to tell whether the save succeeded as
> > > otherwise it won't be able to make the controller decision to say whether
> > > to
> > > cflocation to another screen or to redisplay the form (or whatever
> > > approach
> > > you're using), and it needs to pass the errors along in a way the view can
> > > understand as otherwise the view won't be able to display the correct
> > > error
> > > messages.
> > >
> > > So, whether you make it:
> > > If UserService.isValid()
> > > UserService.save();
> > > location("UserList");
> > > Else
> > > Display Form
> > >
> > > OR
> > >
> > > Success = UserService.Save()
> > > If Success
> > > location("UserList")
> > > Else
> > > DisplayForm
> > >
> > > (o rmore likely, a variant where "Success" is really ErrorCollection
> > > and you test whether ErrorCollection has any members, or is ErrorBean and
> > > test whether ErrorBean.hasErrors())
> > >
> > > In any of these cases you are performing both a command and a query.
> > > The command is to save the data and the query is whether it was saved
> > > successfully. Nothing wrong with turning that into a single mixed method
> > > call (some purists might say you should keep commands and queries
> > > separated,
> > > but I'm not that picky), but it isn't reducing the amount of information
> > > required or the knowledge of the API. You're just doing the command and
> > > the
> > > query in a single line so it isn't making the controller any dumber – just
> > > more concise.
> > >
> > > Best Wishes,
> > > Peter
> > >
> > >
> > >
> > > On 1/15/08 12:56 PM, "Brian Kotek" <[EMAIL PROTECTED]> wrote:
> > >
> > >
> > >
> > > On Jan 15, 2008 11:57 AM, Adam Haskell <[EMAIL PROTECTED]> wrote:
> > >
> > > I'm much more comfortable with doing 2 calls in my service,
> > > model.validate(); model.save(), instead of Model.save() and have the
> > > save do the validation. Doing model.save makes my service not much
> > > more a facade which isn't what I want. Additionally in our environment we
> > > have multiple validaters, some of which should not, in my opinion, be part
> > > of the domain's concern. An example of this would be Enterprise vs domain
> > > specific validation. Something like name is 35 characters and does not
> > > have
> > > cross sit scripting is Enterprise concerns and part of the validation
> > > across
> > > all applications irregardless of domain. Where as address must be in the
> > > US
> > > is domain specific to Contest entries. The converse is true too though if
> > > you put too much in the service layer your domain model becomes anemic.
> > >
> > >
> > > See, I disagree here. I don't think it should be the job of the
> > > calling code to know that this is a two step process. I would call
> > > myService.save(someData) and the validation would happen inside the
> > > model. If you have some higher-level validation that would take place
> > > outside of the actual business object, I would still do that in the
> > > service;
> > > that is its job. I would do that validation inside the service, or more
> > > probably I would build it into the Validators, which means the Validator
> > > might internally be leveraging several specific Validators to do it's job.
> > > So I might do
> > >
> > > myService.save(userData);
> > >
> > > and inside the service I might do:
> > >
> > > user = createUser(userData);
> > > result = createResult();
> > > if (user.isValid()) {
> > > result.setSuccess(true);
> > > }
> > > else {
> > > result.addErrorMessages (user.getErrorMessages());
> > > result.setOriginalData(userData);
> > > }
> > > return result;
> > >
> > >
> > >
> > >
> > >
> > > Adam Haskell
> > >
> > >
> > >
> > > On Jan 15, 2008 8:31 AM, Alan Livie < [EMAIL PROTECTED]>
> > > wrote:
> > >
> > >
> > > Good anecdote but I am confused!
> > >
> > > You said 'in this case the
> > > Service should be earning it's keep and making sure the documents are
> > > valid
> > > and ready for it's client, the model. '
> > >
> > > Are you sure about this? Shouldn't the model be responsible for making
> > > sure things are valid - ie look after itself.
> > >
> > > I see the service more as a smart api that delegates to the model for
> > > all the business logic and also can provide 'application-specific'
> > > functionality like logging, email notifications etc
> > >
> > > But maybe I'm misunderstanding it or taking the anecdote too
> > > seriously! It's more accurate than the MVC song at least :-)
> > >
> > > Alan
> > >
> > > On Jan 15, 12:47 pm, "Adam Haskell" <[EMAIL PROTECTED]> wrote:
> > > > I've used this anecdote before, and I think it is amusing so I'll
> > > use it
> > > > again. The way I think about it is The model and View are going
> > > through a
> > > > divorce and the controller and service are the lawyers. Now thinking
> > > about
> > > > it in these terms, would it make sense for the Controller (the
> > > View's
> > > > lawyer) to be taking care of the Model's Affairs, in this case
> > > validating
> > > > documents for the model? That doesn't make much sense, in this case
> > > the
> > > > Service should be earning it's keep and making sure the documents
> > > are valid
> > > > and ready for it's client, the model. Sure the Controller might
> > > throw in
> > > > some JS for the View to do some preliminary checking so the always
> > > bitchy,
> > > > soon-to-be ex, spouse won't complain but it really is the spouses
> > > lawyer's
> > > > duty to inform the spouse that the documents are valid, or return
> > > the
> > > > documents to some one telling them to try again, no deal. That being
> > > said
> > > > Brian's earlier statement about calling something from Flex really
> > > has
> > > > helped me clear up what should go where. Anecdotes provide a means
> > > to
> > > > getting over the hump but once you are over the hump real life
> > > programming
> > > > drives the point home and Brian's example/thought process is spot
> > > on.
> > > >
> > > > Adam Haskell
> > > >
> > > > On Jan 14, 2008 11:53 PM, Brian Kotek <[EMAIL PROTECTED]> wrote:
> > > >
> > > > > It depends on what you mean by "appropriate methods", but if
> > > you're
> > > > > talking about something similar to what Peter used an an example:
> > > >
> > > > > If (Order.isValid())
> > > > > {
> > > > > Order.save();
> > > > > }
> > > > > Else
> > > > > {
> > > > > Screen = OrderForm;
> > > > > Data = Order;
> > > > > };
> > > >
> > > > > No, I wouldn't be doing that in the Controller (and I think we
> > > might be
> > > > > getting some miscommunication here because I'm pretty sure Peter
> > > and Sean
> > > > > wouldn't either). My Controllers are very dumb. The only thing
> > > they do is
> > > > > ask the Model to perform some business logic (via the service
> > > layer), and
> > > > > then invoke the appropriate views or execute a redirect. That
> > > covers 99% of
> > > > > what my Controllers do.
> > > >
> > > > > The problem with doing something like the above in the Controller
> > > means
> > > > > that the model is no longer neutral and self-contained. I can't
> > > call the
> > > > > service layer from Flex now, because the logic that checks
> > > validity and does
> > > > > saving is executed by the Controller, not the Model. I would have
> > > a method
> > > > > in my service named something like " orderService.saveOrder
> > > (orderData)",
> > > > > and internally that service layer method might create an Order,
> > > validate it,
> > > > > save it, and return a success or failure result that the
> > > Controller can then
> > > > > use to determine how to proceed (cflocation or redisplay form with
> > > errors,
> > > > > for example). I'm pretty sure that this is what Sean and Peter are
> > > also
> > > > > talking about.
> > > >
> > > > > On Jan 14, 2008 9:11 PM, Baz <[EMAIL PROTECTED]> wrote:
> > > >
> > > > > > Sean, Brian, it seems you are both on board with getting a
> > > newUserBean()
> > > > > > from the service in the controller then calling the appropriate
> > > methods on
> > > > > > that UserBean later on in the controller. Do you also handle
> > > queries or
> > > > > > multiple objects in the same way that Peter does? That is, do
> > > you code
> > > > > > gateway-type methods into your service that interact with a
> > > DAO/Gateway to
> > > > > > return multiple instances of your object?
> > > >
> > > > > > Baz
> > > >
> > > > > > On Jan 14, 2008 4:40 PM, Brian Kotek < [EMAIL PROTECTED]
> > > <mailto:[EMAIL PROTECTED]> <[EMAIL PROTECTED]> > wrote:
> > > >
> > > > > > > Absolutely, I didn't mean to imply that the service actually
> > > does
> > > > > > > everything itself.
> > > >
> > > > > > > On Jan 14, 2008 7:35 PM, Sean Corfield <
> > > [EMAIL PROTECTED] >
> > > > > > > wrote:
> > > >
> > > > > > > > On Jan 14, 2008 1:19 PM, Brian Kotek < [EMAIL PROTECTED]>
> > > wrote:
> > > > > > > > > I think he is saying that his controllers only interact
> > > with
> > > > > > > > services. The
> > > > > > > > > easy rule of thumb for me is: if this was called by Flex
> > > instead
> > > > > > > > of my HTML
> > > > > > > > > controller, would it still work? The answer should be
> > > "yes". Which
> > > > > > > > means all
> > > > > > > > > logic of any consequence (beyond doing something like a
> > > > > > > > cflocation, which is
> > > > > > > > > specific to the HTML view anyway) should be handled in the
> > > model.
> > > >
> > > > > > > > Right, but that can still be in the domain object rather
> > > than the
> > > > > > > > service. You just need to expose the API via the service for
> > > remote
> > > > > > > > interaction. It doesn't mean all the business logic is in
> > > the
> > > > > > > > *service* which is at the heart of Baz's question, I
> > > believe.
> > > > > > > > --
> > > > > > > > Sean A Corfield -- (904) 302-SEAN
> > > > > > > > An Architect's View --http://corfield.org/
> > > >
> > > > > > > > "If you're not annoying somebody, you're not really alive."
> > > > > > > > -- Margaret Atwood
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> >
> > > >
> >
>
>
> --
> Paul Marcotte
> Fancy Bread - in the heart or in the head?
> http://www.fancybread.com
--
Paul Marcotte
Fancy Bread - in the heart or in the head?
http://www.fancybread.com
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