From: Aaron Bartell
Do you feel that drop-downs are a waste of time?
No, it's not that. It's just that Niels is getting close to having a turn-key Emulator. One that you could just plug-in and add to a Web site. And ExtJS components already offer a top-grade, professional look.
On the other hand, it appears that Niels may also be offering an interface for developers. One that could potentially be used as server-based middle-ware between a browser client and a 5250 application. And the developer would have the leeway to modify the interface.
If I understand correctly, the "C" wrapper around the 5250 interface could be a big boon. It maps the 5250 data stream to server-side components that can be referenced from RPG middle-ware modules, but shields all the nasty 5250 bits from the RPG coder.
Your RPG middle-ware would just work with arrays of UI components (input-output fields, attributes, and other screen elements), similar to the TN5250J bean that Pete Helgren was working with. In Niels example, there's no J2EE middleware, which is a lot more efficient.
And Niels also came up with an interface between an RPG module and the ExtJS client. But I suppose one could come up with their own messaging protocol between any kind of browser client and any kind of application server, if this were an open-source project.
If you want to add an interface for drop-downs, and have the time, and need more than a plug-in emulator, then that seems to be an option. You could modify the interface on a case by case basis.
For example, your browser client might get the base screen provided by the 5250 program, then evoke an AJAX request to fill in a drop-down list. The RPG module in the middle could handle that request without even notifying the 5250 program (which would be waiting on a "read" opcode). Hey, it's middle-ware. And you write it. You can do what you want.
Nathan.
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