[e4-dev] NLS-System and Eclipse 4.0

[Tom Schindl <tom.schindl@xxxxxxxxxxxxxxx>]

Hi,

Now that we have a fundamental translation stuff for our EMF-Model in
place the next problem I'd like to approach is the useage of the static
NLS-Translation loading which in fact contratics the e4 paradigm of NO
SINGLETONS AND STATICS.

This is the only place left in our code which prohibits multi-instance
scenarios like e.g. RAP run our workbench code as is.

As part of the translation story I've developed an idea of how I think
we should deal with it in an e4 like way.

a) Instead of using static-Fields I think we'll have to use instance-
   fields
   Messages.My_Message => messages.my_message

b) To load translations we provide a factory which creates an instance
   of the field
   NLS.initialize() =>
       IMessageFactory.createInstance(String lang, Class<M> clazz);

   => Configuration through an @Message-Annotation (e.g. to
      overload the default Class-Name => Properties-File name mapping)

   => Built-In cache of Message-Instances so that we don't waste memory
      loading the same translations multiple times into multiple
      instances (including memory management if Message-Instance get
      unused its memory can be freed)

c) Easy usage with DI by adding an annotation @Translation similar to
   @Preference

   @Inject
   @Translation
   private Messages messages;

I've implemented a primary version of this in my
org.eclipse.e4.tools.services bundle (you find it in the post_m5 branch)
and I'm going to port my ModelEditor to use it in the next few days.

Afterwards I'll try to measure this approach so that I can you some
figures. As always with new things the current tooling provided the
Eclipse is not available (like it is for the current NLS-stuff) but I
still think we should find not use NLS in our e4 code base because it
contratics the most central programming pattern we've built Eclipse 4
around.

Tom

-- 
B e s t S o l u t i o n . a t                        EDV Systemhaus GmbH
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tom schindl                                        geschaeftsfuehrer/CEO
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