Re: [platform-ui-dev] Plugin-Reloding

[Nick_Edgar@xxxxxxx]

Kris,

As a starting point, here are a few key interfaces and methods:
In package org.eclipse.core.runtime,
- IPluginDescriptor describes a plugin (it need not be activated).
- Plugin is the main class representing a plugin once it has been 
activated.
- IPluginRegistry is the registry of plugins, obtained from 
Platform.getPluginRegistry()
- IConfigurationElement is an element within a plugin descriptor.
- The createExecutableExtension(...) methods on IConfigurationElement are 
used to instantiate classes referred to by the plugin.
Search for references to this method to see where classes are instantiated 
and where they're hung onto.

Nick





"N V S Rama Krishna" <ram_kri@xxxxxxxxx>
Sent by: platform-ui-dev-admin@xxxxxxxxxxx
01/09/02 04:14 PM
Please respond to platform-ui-dev

 
        To:     <platform-ui-dev@xxxxxxxxxxx>
        cc: 
        Subject:        Re: [platform-ui-dev] Plugin-Reloding

Hi Nick,
      When I was going through your first two paragraphs I had many 
answers
which match with the lines of your thrid paragraph ("It may be possible to
add support for.....).
      I definitely would love contributing to this. Now please tell me the
resouces that I have to go through or atleast point me to it so that I can
start my contribution to the same. Its very much like implementing your
hot-deployment in App Servers where in we reload the whole stuff with a 
new
custom-classloader (I worked with one of this Application Server making
vendors, hence that knowledge). Ya!  ya ! I know its not all that simple 
to
implement and that's exactly why I would like to explore this area and see
to it that none others face the difficulties I am facing while developing
some complex plugins with WSAD.
     Awaiting your mail with the required information and pointers to
appropriate resources. I have this Trial version 4.0 with me.
     Have a nice day !!

Regards,
kris

----- Original Message -----
From: <Nick_Edgar@xxxxxxx>
To: <platform-ui-dev@xxxxxxxxxxx>
Sent: Monday, January 07, 2002 8:57 AM
Subject: Re: [platform-ui-dev] Plugin-Reloding


> While it would be useful to be able to shut down and restart a plugin
> during plugin development, it's not clear that this is a trivial thing 
to
> add simply because each plugin has its own classloader.
> There is no way to forcibly shutdown a classloader.
> A classloader is only garbage collected when there are no longer any
> references to it or any classes it has loaded, including any instances.
> To do so would require closing all open views and editors from the 
plugin
> in question, resetting any activated action contributions to their
> pre-activated state, etc.
> If any references remained to any of these parts, the classloader would
> stick around.  This can easily happen, for example if a view hooks 
itself
> as a part listener, but forgets to unhook on dispose().
> Note that it's not just UI components you need to be concerned with,
> either.  In fact, shutdown protocol would probably have to be added to 
the
> Plugin class since a basic shutdown mechanism itself could not know how 
to
> tell all parts to shutdown.
>
> It may be possible to add support for shutting down a plugin, by taking 
a
> best effort approach at shutting down all its parts, then creating a new
> classloader for the plugin the next time it is activated.
> But this would not be a trivial effort to add.
>
> Our schedule is pretty well full for 2.0.  If you would like to
> investigate this area, we would certainly encourage you, and would be
> interested in any results you come up with.
>
> Nick
>
>
>
>
>
>
> "N V S Rama Krishna" <ram_kri@xxxxxxxxx>
> Sent by: platform-ui-dev-admin@xxxxxxxxxxx
> 01/02/02 07:41 PM
> Please respond to platform-ui-dev
>
>
>         To:     <platform-ui-dev@xxxxxxxxxxx>
>         cc:
>         Subject:        [platform-ui-dev] Plugin-Reloding
>
> Hi !
>    I strongly feel there should be a provision in WSAD with which one 
can
> reload the plugin instead of closing down the IDE and then starting it
> again. Since each plugin is loaded by a different class-loader
> implementing this shouldnt be a deal !!!
>    Any comments on this ?
>
> Regards,
> Kris
>
>
> _______________________________________________
> platform-ui-dev mailing list
> platform-ui-dev@xxxxxxxxxxx
> http://dev.eclipse.org/mailman/listinfo/platform-ui-dev


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