Re: Changes to Events API

Hi Libor,
no, it isn't possible. Cyclic composite relations are forbidden in MOF 
(you get CompositionCycleException if you try to create cyclic 
composition) - i.e. if something is a component of A, it cannot be 
container of it (neither directly nor transitively).
Martin

Libor Kramolis wrote:
> Hi Martin,
> 
> thanks for proposal. I will use it in XML case. I have just one 
> question, do you consider a *cycles*? It is not problem of XML model, 
> but in general it is possible, isn't it?
> 
> Thanks,
> Libor
> 
> 
> Martin Matula wrote:
> 
>> Hi,
>> from the discussions that I saw at some external mailing lists and 
>> from the discussions I had with the people here at Sun that intend to 
>> use the  MDR it showed up that what would be a good thing to have is a 
>> possibility to listen to events on objects' containers (composites). 
>> This means that the events should be propagated not only up to the 
>> proxies, but also to objects' composites. This way someone who wants 
>> to listen to any changes in a Java class would listen to the class 
>> only (and would not be forced to register listeners to all the 
>> methods, their parameters, attributes, etc.) The same is applicable in 
>> many other cases (UML metamodel, XML, etc.)
>> Thus I propose that events on RefObjects are propagated also to their 
>> composites. Once the event gets to the composite, it will be 
>> propagated to its composite, but not to its proxies (thus the current 
>> event path via proxies would be followed only for events originating 
>> from the given RefObject). I.e.:
>>
>> APackage extent contains AClass and BClass class proxies, A is 
>> instance for AClass, B is instance for BClass.
>> A is a component of B, A is changed -> event goes to A, from A to 
>> AClass and B, at B it is forgoten, from AClass it goes to APackage, 
>> from APackage it goes to repository.
>>
>> Now the question is, how the listeners should register for the events 
>> from containers. I would like to add method addListener(..., boolean 
>> includeComponents), however this would be applicable only for 
>> registering listeners on RefObjects. Should there be a special 
>> RefObjectEventSource for RefObjects? Any suggestions are welcome.
>> Martin
>>
>