[eclipselink-users] EclipseLink and Eclipse Databinding

[Johannes Michler <orgler@xxxxxxxxx>]

Hi,

I'm facing another Problem when using Eclipselink as my persistence Layer. I've got the following 3 Tables: Users, Groups, User_Group_assigns (assigns users to groups, specifying valid-from and valid-to for the assignment).

I'd like to have some simple rcp-dialogs to edit the users and groups. For the user-editing I'd implement a Table with users. When selecting a entry of the list, The userproperties and a list of assigned groups is displayed for editing. I got this to work using eclipse-databinding on the eclipselink annotated entity-objects without problems. But in the next step, I'd like to put my data-access-layer on a server, accessing it using webservices. I think it's not a good plan to expose the entity-"beans" directly over the web. Are there any known and good patterns to solve this problems? I thought of writing kind of transfer-objects to transfer the user- and groupdata. But how could I easily record which elements have been changed by the GUI sending back to the server only them? Without doing manual merging? Manual merging on the client would be quite difficult, especially for the assigned groups for a user and in the scenario of having multiple changes (create/update/delete of user/userassignments). One way to do propagate the changes immediately to the server, but I consider this quite ugly because it would prevent me from easily quitting the dialog using "Cancel".

Any hints or well-known-solutions to such problems?

-Johannes