Re: [platform-update-dev] Install handlers and SWT/JFace

[Dejan Glozic <dejan@xxxxxxxxxx>]

Install handlers are instantiated using the same class loader that loads
update core classes. This means that it only 'sees' classes that are on the
dependency list of the Update Core plug-in. There is a good reason for
this: features with install handlers must allow command line installation
i.e. when running in a headless mode (no UI). Obviously, a feature that
wants to put up a dialog during the installation cannot be installed from a
command line.

In the past, Team component attempted to solve a similar problem in
repository providers by providing a type-neutral parameter call 'context'
(of type Object). Obviously, Team Core component has no idea what this
'context' object is, but Team UI component passes the parent shell object,
allowing the client code to put up dialogs and other visual controls. The
key is that this object can be null (when the provider is instantiated in a
headless mode), so the provider implementers must have a strategy for this
scenario.

I will let Dorian Birsan who owns Update take over the topic (in particular
if the Team approach is possible in the context of Update).

Regards,

Dejan Glozic, Ph.D.
Manager, Eclipse Development 1A
D1/R0Q/8200/MKM
IBM Canada Ltd.
Tel. 905 413-2745  T/L 969-2745
Fax. 905 413-4850



                                                                           
             "Sally, Gene"                                                 
             <Gene.Sally@times                                             
             ys.com>                                                    To 
             Sent by:                  <platform-update-dev@xxxxxxxxxxx>   
             platform-update-d                                          cc 
             ev-admin@eclipse.                                             
             org                                                   Subject 
                                       [platform-update-dev] Install       
                                       handlers and SWT/JFace              
             09/07/2004 05:28                                              
             PM                                                            
                                                                           
                                                                           
             Please respond to                                             
             platform-update-d                                             
                    ev                                                     
                                                                           
                                                                           




Hi,

I've seen various posts (on this mailing list and others) about using
graphical widgets from a custom install handler but I haven't seen
anyone who got this working.  I'm trying to run a class in a jar file
packaged along with the feature, and apparently, the classpath in this
context does not have any references to the graphical plug-ins.

It appears like one solution to this problem is installing a feature
that registers a plugin under the
org.eclipse.update.core.installHandlers and then have the user run the
update manager again to install a feature that references the newly
installed installHandler which has the correct classpath and can then
present the user with dialogs, etc.  While a good work-around, I think
potential users would find this procedure a bit awkward.

Is there a way to configure an custom install handler that can use SWT?
If not, is there something on the road map?  Does an example or some
documentation for this usage pattern exist that I've managed to miss?
I'd sincerely appreciate any pointers you could send my way. :-)

FWIW, The installation I'm considering would require at least a few
dialogs worth of data during installation and it appears like, the best
route would be to use a third party tool to tackle this problem.


Thanks,

gene

_______________________________________________
platform-update-dev mailing list
platform-update-dev@xxxxxxxxxxx
http://dev.eclipse.org/mailman/listinfo/platform-update-dev