I am new to WDA style of UI development, though not new to WD. I did some study on the way certain UI features behave in WDA. I have several questions on the design patterns followed in this tool.
I have to develop a set of UIs that connect to services. Ofcourse I would use the service call option in WDA. How to use UI elements such as Range selector, search helps when I use only services as models. I dont wish to use any local data elements. The approach is service aligned and all data types used belong to GDT (GlobAL DATA tYPES IN ESR).
I have seen that the range selector uses a data element in ABAP and the WD generator automatically creates a range selector UI. The data feteched comes from the local server where the data element exists (pls correct me if iam wrong). What happens if my data element really exists on a different ABAP server? How to develop distributed WDA applications? What are the best practices?
I wish to keep services & webdynpro UI in different ABAP systems. UI will call the services via the service call option in WDA. I dont want to create single instance monolithic applications. Even better I would choose PI is moderator to facilitate Asynchronous service calls.
Does WDA really allow/force you to applications based on MVC patterns? I read this blog post, it does discuss the issue but what are the design guidelines to follow? Thanks.
Edited by: LNV on Jul 28, 2010 9:22 AM
>How to develop distributed WDA applications?
The primary design consideration for WDA is not distributed applications. WDA is mostly designed for creating WDAs that sit directly within the same instance as the application services it is consuming. This isn't to say that you can't have a distributed application, but there isn't much framework support. For instance you really can't use DDic search helps in this situation. You will need to use Freely Programmed or OVS search helps and call another service to retrieve the search results (fairly similiar to WDJ in this regard).
>I wish to keep services & webdynpro UI in different ABAP systems. UI will call the services via the service call option in WDA. I dont want to create single instance monolithic applications. Even better I would choose PI is moderator to facilitate Asynchronous service calls.
I guess the question is why? This isn't the norm with WDA. One of the advantages of WDA is that you don't have to separate the UI layer onto a separate instance or platform. Having the UI and application on the same instance doesn't mean you can't follow good MVC. One of the things that SAP has learned over the year is that having too much sepratation between the UI and the application layers leads to inefficencies in reuse, development and performance problems. This is why you see Suite WDJ applications being rewritten in WDA and part of the major redesign that took place with Business ByDesign. Please consider the cost that you incure in such architecture vs. the benefits you seek.