From Java CoG Kit

Gregor von Laszewski and Mike Hategan

Contents 1 Abstract 2 Comparision with BPEL 3 Comparison with XUL 3.1 What is XUL? 3.2 What are Karajan Forms? 3.3 How does a program look 3.4 What are the similarities?

Abstract

In this article we compare the Java CoG Kit Karajan framework with other approaches that come in mind when looking at particilar technologies that are addressed by it. IN particular we will focus on a comparision between Karajan and BPEL, between Karajan and XUL.

Comparision with BPEL

Include the text from the presentation

Comparison with XUL

What is XUL?

Include the text from the presentation
what is xul? (Hategan)

XUL:

• describes GUIs for Mozilla
• extensive (possibly complete)
• abstract (no specific toolkit dependency)

What are Karajan Forms?

Forms:

• Karajan library. Eveything in it is bound to all Karajan rules. In other words, it is executable.
• uses Swing (but it is abstract, so I guess it could be bound to other GUI Toolkits)
• not complete. It only contains a few GUI elements at this time
• lacks a mechanism for form updates (cannot, for example, change the label of a button after the form was made visible)

How does a program look

Karajan:

<form...>
  <for name="label" in="Ok, Cancel, Not Sure">
    <form:button caption="{label}"/>
  </for>
</form>

XUL (you need JavaScript):

<window...>
  <script>
    var x
    var a = new Array("Ok", "Cancel", "Not Sure")
    for(x in a){
      document.write("<button label=\""+a[x]+"\"/>\n")
    }
  </script>
</window>

(I'd say the JavaScript thing is a hack).

What are the similarities?

• both are declarative
• both use vboxes and hboxes for layouting (In Karajan it was inspired by GTK)

The biggest difference is that XUL defines a language (domain specific), while the forms lib is a library that uses the Karajan data and processing model to implement forms on top of currently Swing. The similarities in the way they look might be coincidental (but it may be that they were both inspired by the same things).