From: Clifford Heath <cjh_nospam@...>
Date: 2002-07-25T14:48:58+09:00
Subject: Re: GUI's and the Rouge, Part III (yes, finally) 1/2

Albert Wagner wrote:
> OpenUI sounds fantastic.  But, it was known beforehand that OpenUI would be
> the UI.  Could the same Oracle code be connected to another UI without
> modification?  Or was it unique to OpenUI?

Any UI platform - Windows, Motif, Mac, OS/2 and character terminals, and
almost any Unix or Windows server platform. But OpenUI provided more than
just a UI toolkit, so perhaps not. The point is that you could have built
any UI using OpenUI and it would still work - in fact we sometimes
completely redid a UI without even recompiling the backend code.

In particular the client/server communications were built around async
messaging with particular delivery methods and expectations, and the UI
was animated by code running in the VM. A replacement UI would have to
mimic those characteristics. I did write a Java version of the server side
of the messaging protocol once, it was about 2,500 lines of code, so not
too hard - the client side is almost identical. The message delivery
algorithms were based on highly optimised data structures, but otherwise
were unremarkable. Add those features to the XP GUI toolkit, wrap the whole
thing in a VB-like drag-drop IDE and interactive symbolic debugger both
written in OpenUI, and you have the whole package. For the toolkit, we
chose the path of wrapping the native widgets on Motif, Windows, Mac,
OS/2 and a curses-style windowing package for terminals. In retrospect
that was a mistake, I think Qt's emulation path is better. The native APIs
are too buggy. Just a shame that Java came along and cruelled the pitch
for us.

--
Clifford Heath