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Compute Dependencies for Feature [message #498794]

Wed, 18 November 2009 11:19

Eclipse User

Hello,
I use the Compute button of the Dependencies tab, to add required plugins to my feature (feature.xml file). But the action adds twice the same plugin with different versions. I don't understand how these plugins are computed, because in the Plug-ins tab the version of the plugin doesn't match with the two others.

Someone would kown the process of this compute action?

Thx,
David.

Re: Compute Dependencies for Feature [message #498820 is a reply to message #498794]

Wed, 18 November 2009 12:51

Eclipse User

Hello David,

OSGi makes it possible (and that is one of the great features) to load
multiple versions of the same bundle. This means that bundle A can depend an
bundle Bv1 and bundle C. Bundle C can depend on Bv2. The final graph then
looks like this:

A --------C------B(V2)
|
B(V1)

When A needs a class from B then it uses the V1 bundle, if C needs a class
from B then it uses the V2 bundle.

Note that Eclipse plug-ins are singletons (a plug-in is a bundle that uses
the extension point mechanism and therefore has a plugin.xml file) . This
means that this versioning does not work with those (defined like this:
Bundle-SymbolicName: org.eclipse.ecf.provider.twitter.ui;singleton:=true)

Hope this clarifies it.

Wim Jongman

> Hello,
> I use the Compute button of the Dependencies tab, to add required plugins
to my feature (feature.xml file). But the action adds twice the same plugin
with different versions. I don't understand how these plugins are computed,
because in the Plug-ins tab the version of the plugin doesn't match with the
two others.
>
> Someone would kown the process of this compute action?
>
> Thx,
> David.

Re: Compute Dependencies for Feature [message #498915 is a reply to message #498820]

Thu, 19 November 2009 03:17

Eclipse User

Hy Wim,
thanks for your answer.

When I use the Compute button, the action adds in the required plugin :

<import plugin="com.ibm.icu" version="3.8.1.1" match="compatible"/>

But in my generated RCP, when I try to install a new software, I have a problem with the configuration, as the new software needs this plugin with an other version. And when the plugin I want to add is in my configuration, the required version is also 3.8.1.1.

What can I do to have the good version with the compute action?
Thx,
David.

Re: Compute Dependencies for Feature [message #499028 is a reply to message #498820]

Thu, 19 November 2009 10:20

Eclipse User

Hi all,

Wim Jongman wrote:
> Note that Eclipse plug-ins are singletons (a plug-in is a bundle that uses
> the extension point mechanism and therefore has a plugin.xml file) . This
> means that this versioning does not work with those (defined like this:
> Bundle-SymbolicName: org.eclipse.ecf.provider.twitter.ui;singleton:=true)

Do you mean that all plug-ins necessarily have to be singletons or only
those that are shipped in the Eclipse platform happen to be singletons?

Would it make any sense to have two different versions of the same
plug-in (contributing similar extensions) deployed in the same application?

Alex

Re: Compute Dependencies for Feature [message #499181 is a reply to message #499028]

Fri, 20 November 2009 05:21

Eclipse User

Hi Alex,

> Do you mean that all plug-ins necessarily have to be singletons or only
> those that are shipped in the Eclipse platform happen to be singletons?

if they have a plugin.xml then they have to be. You get an error if you use
or supply extension points in the plugin.xml but the singleton directive is
not set.

>
> Would it make any sense to have two different versions of the same
> plug-in (contributing similar extensions) deployed in the same
> application?

No it wouldn't. This approach makes sense if you think about the user
interface. Eclipse builds the UI by looking at the plugin.xml before the
actual code starts. In the xml e.g. there is a menu contribution "Exit" to
the main menu. If Eclipse would allow two versions of the same bundle it
would get two "Exit" menu entries.

--
Best Regards,

Wim Jongman
http://www.remainsoftware.com
http://www.industrial-tsi.com

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