[news.eclipse.platform] Re: IAdapterFactory vs. adapters extension

[martin <address.starts.after.hyphen-martin.umgeher@xxxxxxxxxxx>]

Roman Mukhin wrote:
> Hi Martin
>
> IAdapterFactory and its extension org.eclipse.core.runtime.adapters 
> allow other people to extend you UI model. They can attach transparently 
> some additional interfaces (i.e. implementations of those interfaces) to 
> you model.
>
> Look at FAQ 126 Official Eclipse 3.0 FAQs (How do I use IAdaptable and 
> IAdapterFactory?). It exaclty answers your question.
>
>
> I think the classical example would be to use:
>
> 1. Inherit you UI model from PlatformObject (or implement IAdaptable 
> through look up with IAdapterFactory)
>
> 2. Provide IWorkbenchAdapter (IWorkbenchAdapter2) using extension point 
> (org.eclipse.core.runtime.adapters) (at the package org.eclipse.ui.model 
> you will find some base and ready to use classes)
>
> 3.  Now you can use (or inherit) WorkbenchLabelProvider, 
> BaseWorkbenchContentProvider, WorkbenchViewerSorter to display for 
> example using TreeViewer you model. You model does not have any UI code.
> And other way somebody could display your object even know  nothing 
> about your UI model interfaces.
> ---------------------------------------------
> This case is described in FAQ 177 (The Official Eclipse 3.0 FAQs):
> ---------------------------------------------
>
> Another example: you can attach implementation of your interfaces from 
> your plug-in to existing Models of another plug-in. A lot of extension 
> points support object filters with adaptable=true/false parameter. That 
> is a hook to you attached implementations.
>
>
>
> I hope it gives you a hit where to read more about it
>
> - best regards
> Ram
>
> martin wrote:
> > Hi,
> >
> > can anyone explain to me why one has to implement IAdapterFactory with 
> > its method getAdapterList AND additionally specify all adapter types 
> > in plugin.xml when using the org.eclipse.core.runtime.adapters 
> > extension? Seems kind of redundant to me...
> >
> > Regards,
> > M


Thanks a lot for your explanations. I alreay use and (to some degree) 
understand the adapter mechanism, but wasn't aware yet of the 
workbench-level stuff.

But I still don't get the thing about adapter types. When I use the 
extension point to register a class as adapter factory, the class has to 
be an implementation of IAdapterFactory, which requires to provide an 
implementation of #getAdapterList. This method returns an array of 
supported types. I also have to provide the same list of supported types 
in plugin.xml (in the extension editor of PDE, they are children of the 
factory nodes below org.eclipse.core.runtime.adapters). Why do I have to 
 specify the supported types twice?

M