Re: [e4-dev] Improved handling of ID's - Suggestion for discussion

[Tom Schindl <tom.schindl@xxxxxxxxxxxxxxx>]

Am 31.01.12 22:03, schrieb Brian de Alwis:
> I think an example of what Lars is talking about is to allow referencing an identifier from within a .e4xmi file that is actually defined in source code.  This would allow single-sourcing of an identifier.  
> 
> For example, say we have a command defined for org.eclipse.ui.exit, and some code that wants to programmatically execute this command.  Currently we'd define the command in an e4xmi file:
> 
> 	<commands elementId="org.eclipse.ui.exit" />
> 
> And then also reference the command identifier from a source file:
> 
> 	public class MyPart {
> 		public static final String EXIT_ID = "org.eclipse.ui.exit";
> 
> 		// does this work?
> 		@Inject @Named(EXIT_ID) MCommand exitCommand;
> 		@Inject EHandlerService hs;
> 
> 		public void executeExit() {
> 			hs.executeHandler(new ParameterizedCommand(exitCommand, null));
> 		}
> 	}
> 


Ok that make sense but I guess this should read @ModelId() instead of
name, not?
			
> Currently, org.eclipse.ui.exit has to be used both in the .e4xmi file defining the command, and in the code.
> 
> Lars' suggestion would change the e4xmi to something like:
> 
> 	<commands elementId="model://bundle/MyPart/EXIT_ID" />
> 

Ok I see.

> That would cause the command's elementId to be looked up (and validated!) at runtime; mismatches could be reported.  (I guess either ApplicationElementImpl#[gs]etElementId() would need to hook in some resolver.)
> 
> But I see one possible problem: what should happen if the bundle is unloaded or replaced — and the identifier is now different?  I suppose since almost all objects now use references, it may only be an issue with fragment's imports.
> 
> [Incidentally, why is it that the e4xmi elements are plural? <commands/>, <handlers/>, <bindings/>, <addons/>…]
> 

It's the name of the feature!

Tom

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