Concurrency, BlazeDS, data-driven architecture, and Broadchoice Workspace

Broadchoice Workspace has a contact list on the right-hand side. In the launch release we're working on now, it shows everyone you're connected to through groups. Simple enough, right? A simple SQL query that joins you to groups, and groups to member, and there you go.

It's at this point working on a RIA becomes very different from working on a HTML application.

Here's a few of the more fun use cases to consider. They're fun brain-teasers for thinking about how to handle multiple clients running the application.

Concurrent Signup

1. You're a member of the Acme, Inc. group. Workspace is running.
2. The owner of the Acme, Inc. group starts the Workspace and adds Ferd McBurfle, a new hire from down in accounting.
3. Ferd gets the invitation e-mail and signs up for the application, joining the Acme, Inc. group. He should now should up in your contact list. No user gesture should have to be taken on your part: no refresh, no waiting for a periodic refresh, etc.

People View in a Group

1. After the prior case is complete, you decide to check out the "People" tab in "Acme, Inc." Right now it shows you, the owner, Ferd, and Lumpy McGiblet, the person Ferd just replaced
2. While you're viewing the people tab, the owner removes Lumpy McGiblet.
3. You're not in any common groups with Lumpy anymore, so Lump should disappear from your client's view of people. Again, no gesture should have to be required on your part.

Our Approach

I've really enjoyed working on problems like this on the Workspace. Our solution to most of these situations involves using server-side services that broadcast small DTOs to running clients via JMS, "pushed" through amf-polling. Many of these same concepts are possible in ColdFusion, as well.

If you'd like to hear more about this kind of work, feel free to stop any member of the ArgumentCollection at Adobe MAX next week!