There may be cases where this is permissible. For example, a MapWidget might return LatLng objects, rather than having a Long and Lat field which are separately bound. In the context of OpenSocial or GData, I could see a common reusable widget for picking from your network that would naturally return something like a Person. The reason it might do this, is because the binding itself might be overly complex. The widget might present friends in a tree of groups, allow search, pull from multiple networks. In general, the internal state of the widget might be too complex to expose for binding to via getter methods.
-Ray On Thu, Oct 9, 2008 at 2:23 PM, Emily Crutcher <[EMAIL PROTECTED]> wrote: > Would you normally have a UI widget as specific as a person picker? That > seems like the model (a person) and the widget displaying the person might > be a bit too closely bound, and we'd rather that binding took place using > some sort of data binding solution. > > The reason for this distinction is to make it clear that the HasValue > interface is not designed to be a data-binding solution, it is designed to > enable other people to create data binding solutions. > > > > > > On Thu, Oct 9, 2008 at 4:55 PM, Isaac Truett <[EMAIL PROTECTED]> wrote: >> >> [+gwt-c] >> >> ---------- Forwarded message ---------- >> >> > Accordingly, HasValue should only ever be used for simple leaf types on >> > leaf widgets. >> >> I think I object to issue with this statement, but first I'd like to see a >> definition of "leaf" types and widgets. By leaf type, I assume you mean >> primitive wrapper classes and String, but why is Date thrown in there? Why >> would DatePicker implements HasValue<Date> be acceptable but not >> PersonPicker implements HasValue<Person>? What's to be gained by >> discouraging HasValue for complex data types? >> >> >> >> On Thu, Oct 9, 2008 at 4:15 PM, Emily Crutcher <[EMAIL PROTECTED]> wrote: >>> >>> To give you an idea of where I am coming from, here is my understanding >>> of the world: >>> >>> Metadata Systems, comprising Models and Controllers >>> xforms, Ian's databinding system, Arthur's validation system, gwt team's >>> upcoming proposal for data management: >>> >>> All part of the larger metadata, binding, code generation class of >>> systems. Hopefully all of these can eventually use the same basic concepts >>> and it going to be a huge undertaking to get it right. In fact, so huge of >>> one that the gwt team has decided to duck for now and are trying very hard >>> not to get involved in these discusions at the current time. >>> >>> >>> Widget bridge classes, part of the application's view. >>> Classes used to expose the application's view to the meta data systems. >>> >>> HasValue: Provides the bridge between the metadata model and the world >>> of widgets. From the meta data system's point of view it has some way of >>> creating/linking with instances of HasValue<String>, HasValue<Boolean>, >>> HasValue<Date>, etc.. >>> >>> From the widgets point of view, we have a whole bunch of text boxes, text >>> areas, date pickers, etc. on the page. >>> >>> Accordingly, HasValue should only ever be used for simple leaf types on >>> leaf widgets. >>> >>> EventHandlers: Provides a way for the meta data system controllers to add >>> callbacks to react to widget changes. >>> >>> >>>> >>>> -Ray >>>> >>>> >>>> >>>> On Wed, Oct 8, 2008 at 7:15 AM, Ray Ryan <[EMAIL PROTECTED]> wrote: >>>> > We all seem to be talking about data binding and validation a lot, and >>>> > some >>>> > of us are even implementing code about it. We on the GWT team hear the >>>> > need >>>> > and feel it ourselves. >>>> > >>>> > We have some notions of how we'd like to tackle this in a way that >>>> > blends >>>> > seamlessly with the rest of GWT, and are looking to start design and >>>> > implementation in earnest before the year is out. This makes it >>>> > unlikely >>>> > that we'll accept core or incubator patches that implement such a >>>> > system. >>>> > That said, we don't want to shoot down the excellent work that's being >>>> > done! >>>> > If you have a system that's shaping up to meet your needs and that you >>>> > want >>>> > to share with the GWT community, please do! Set up a Google Code >>>> > project, >>>> > announce it here, embarrass us by shipping first and attracting a user >>>> > base. We'll probably steal from you shamelessly and ask for your help >>>> > as our >>>> > own system takes shape. >>>> > I hope this doesn't ruffle any feathers, and that you'll understand >>>> > why we >>>> > haven't been as responsive on some of these threads as we should have >>>> > been. >>>> > Thanks, >>>> > rjrjr >>>> > >>>> > >>>> > > >>>> > >>>> >>>> >>> >>> >>> >>> -- >>> "There are only 10 types of people in the world: Those who understand >>> binary, and those who don't" >> >> >> >> > > > > -- > "There are only 10 types of people in the world: Those who understand > binary, and those who don't" > > > > --~--~---------~--~----~------------~-------~--~----~ http://groups.google.com/group/Google-Web-Toolkit-Contributors -~----------~----~----~----~------~----~------~--~---
