Re: The "Presentation" Layer

Dr. Syd Nicholson wrote:

Yes Joe,

I think the big difference between us is that I only have data in the
response from the server. All requests are Ajax based. There is nothing in
the response from the server that defines the data, whether or not to
display it, or what type of field it is. The server has no idea what client
it is talking to, it could be a browser or a web service on another system.
I rely on the "Store" objects in the JavaScript to hold the data
definitions, and JS Widgets o handle the display.

A different approach, but all equally valid.

I think I misstated my position a little. I agree 100% that the data messages are purely data. The definition of the field itself (the metadata) is sent as part of the widget. I do believe that ultimately the definition of the field should come from the server; you have to ensure that the data in the message and the definition in the widget agree. And that's one of the nice things about EGL. When you define a field, you define the metadata. A record can then be used either to build the UI from the metadata, or to build the data structure to hold the data. But the relationships are always there.

No, the data message itself only contains the data. There is also a separate error information structure, and the relationship between the two is subject to the architecture. But you do have to have some way of returning to the user interface that certain fields in the message are in error, and what that error is.

Joe