[news.eclipse.technology.equinox] Re: Integrating Swing apps on top of E

[Dann Martens <dann@xxxxxxxxxxx>]

I'll spare you a lecture on 'Krusty, the Swing App', but there is some 
evidence that your attempt is indeed akin to a trapeze act in an 
entertainment setting (Honk! Honk!).

None of your issues are in any way OSGi-, or Equinox- for that matter, 
related.

Granted, since Swing libraries are now by default a part of the Java 
platform, Java's 'Parent Delegation' class-loading model will resolve 
the Swing classes at the level of the Bootstrap class loader. Any static 
assignment is scoped at that level in the class loader hierarchy and is 
therefore out of your control. That's the idea of 'trusted classes' in 
security model 1.2 for ya ;)

Your solution is the only possible solution to your conundrum (even more 
elaborate constructions excepted).

You might feel that this is a hack, but I have reason to suspect that 
the uncomfortable feeling you are experiencing is probably your local 
usability engineer who has clawed her- or himself around your throat out 
of desperation. Congratulations! You have managed to build the 
mythological two-headed monster. A single application with two (2!) 
simultaneous Look and Feels for the price of one. With an added surprise 
effect of indeterminate behavior.

Is this a project for Cirque du Soleil?

Or is your product manager simply a slow starter? Is her or his mind 
wandering because of an impending foreclosure? Have you been refused 
escalation because she or he advocate non-violent protest?

As far as I can tell, this is not an engineering problem. It's one of 
those cases which demonstrate how some IT projects can go 'weird' 
without anyone raising a finger or going: 'Hold on a minute!'

This picture might be helpful to print in poster format at your office:
http://images.google.be/imgres?imgurl=http://thevoiceforschoolchoice.files.wordpress.com/2009/07/square-peg-round-hole.jpg&imgrefurl=http://thevoiceforschoolchoice.wordpress.com/2009/07/14/traditional-public-schools-not-ideal-for-every-child/&usg=__AhH3vppZRw8LQMIevX9rWdJIGqM=&h=414&w=290&sz=90&hl=nl&start=1&um=1&tbnid=OFS1I0TWuvRyVM:&tbnh=125&tbnw=88&prev=/images%3Fq%3DSquare%2BPeg%2Bin%2Bthe%2Bround%2Bhole%26hl%3Dnl%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DN%26um%3D1

You're welcome,
 Dann



Eva Troels wrote:
> Hi everyone,
>
> We have two old, crusty Swing apps that we want to integrate on top of 
> Equinox.
> There are several reasons for this decision the most important ones being:
> - No clashing third party libraries (the two apps run different versions 
> of xerces, velocity, and several other open source products)
> - Dynamic updates (the apps can be updated independently of each other)
>
> I am fairly new to OSGi and Equinox and have experienced my share of 
> ClassNotFound and Class Cast Exceptions over the last few weeks.
>
> Now, the two apps run and all is good. Almost. We had to do a few 
> workarounds. The one bothering me the most is the fact that we had to 
> change the applications' Look and Feel:
>
> The applications both have Swing GUIs. This is easy: Just let the two 
> bundles import javax.swing and start popping up the JFrames.
>
> But...The two apps have different look and feels. And these are setup 
> with calls to static methods in Swing. So the result depends on the 
> launch order. If app A wins the look and feel tug of war, the two 
> applications run albeit application B looks a bit different than usual. 
> If app B gets its way app A craches.
>
> How to avoid this and let the two applications have each their look and 
> feel - isolation with regards to Swing packages.
>
> My one solution is: Extract Swing classes for Java's rt.jar and create 
> two new bundles:
> - SwingBundleWithAppALookAndFeel
> - SwingBundleWithAppBLookAndFeel
> and then setup the bundle interdependencies accordingly.
>
> This, however, feels like a major hack and I'm not even sure, that it 
> works.
>
> Please feel free to share any comments!