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| Re: isFactoryForType implementation guideline for adapter factories used by AdapterFactoryContentPro [message #1735089 is a reply to message #1734929] |
Wed, 15 June 2016 13:34   |
 Ed Merks
Messages: 33141
Registered: July 2009 |
Senior Member |
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Thilo,
Comments below.
On 14.06.2016 15:57, Thilo Bohr wrote:
> Hi all
>
> I want to register adapter factories that provide adapters from EMF
> objects defined in multiple model packages to jface content and label
> providers.
> Guided by
> http://help.eclipse.org/juno/topic/org.eclipse.emf.doc/references/overview/EMF.Edit.html
> I configure a TreeViewer with an AdapterFactoryContentProvider and an
> AdapterFactoryLabelProvider, which are initialized with a
> ComposedAdapterFactory.
A common idiom is to use
new
ComposedAdapterFactory(ComposedAdapterFactory.Descriptor.Registry.INSTANCE)
This way all registered item provide adapter factories will be used as
needed. You can add specialized adapter factories to this composed one
to override registered ones...
>
> I learned that the framework calls the isFactoryForType method for
> each registered AdapterFactory multiple times to decide whether the
> adapter factory can provide a suitable adapter or not.
> The javadoc is not to clear about what is tested there, i.e. to which
> set of type objects the adapter is expected to conform.
It's a rather plastic API.
> For example, there are package objects being supplied as input types
> but it is unclear for me for what reasons.
To find the specific item provider adapter factory for that package.
> Moreover, I learned that if multiple adapter factories conform to a
> specific set of calls to isFactoryForType, just the first adapter
> factory will be used to provide adapters.
Yes, the list is searched sequentially.
>
> What are the rules of how the isFactoryForType is used by the
> framework (specifically the ComposedAdapterFactory and the
> AdapterFactory[Content|Label]Provider setup)?
The most important method is
org.eclipse.emf.edit.provider.ComposedAdapterFactory.getFactoryForTypes(Collection<?>)
for selecting an adapter factory to use. And that's driven from
org.eclipse.emf.edit.provider.ComposedAdapterFactory.adapt(Notifier,
Object, boolean) which needs to create an adapter.
> How are the isFactoryForType methods to be implemented if multiple
> adapter factories for multiple EMF models (packages) are to be
> registered?
You can look at generated implementations and you can use the debugger
to answer very detailed questions. The general idea is that given an
object of some type T (and that type is from some package P) and the
desire to create an adapter of some type X, you need to find a factory
that can create adapters of type X for typed T from P so that's why you
see isFactoryForType being called with X and P (with the later being the
case because a factory is registered on a per-package basis).
> Greetings
> Thilo
>
Ed Merks
Professional Support: https://www.macromodeling.com/
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