Re: EOEnterpriseObjectClazz with interface
Re: EOEnterpriseObjectClazz with interface
- Subject: Re: EOEnterpriseObjectClazz with interface
- From: Johann Werner <email@hidden>
- Date: Tue, 20 Nov 2018 10:39:15 +0100
Hi Mark,
I think you have to tell us what exactly you want to achieve? Do you have an
example?
With the EOEnterpriseObjectClazz you have a static instance within your class
but this instance is… an instance so you could put an „implements interface“ on
it. Or if you just want to know if class A has a static clazz object you could
create some empty interface (IHasClazzObject) as marker.
jw
> Am 19.11.2018 um 22:12 schrieb Morris, Mark <email@hidden>:
>
> Hallo Johann,
>
> Thanks for the info. I do see how I could create a default implementation of
> the “static” method I’m expecting in our local EO superclass’s util inner
> class, and from then on know that it will be legal to call it from any of our
> subclasses. So that could work in this case.
>
> In general though I still don’t see how, or if it’s even possible, to do what
> I was originally trying with the interface. For instance methods, I can just
> test “myClass instanceof myInterface” and know whether that class implements
> the methods. In ObjC, I could do the same with a protocol, but with instance
> and class methods. It seems like the description of the clazz paradigm is
> saying it makes that possible, but I’m just not understanding how that works.
>
> Thanks again. Tschüß!
> Mark
>
> From: Johann Werner <email@hidden>
> Date: Monday, November 19, 2018 at 1:37 AM
> To: "Morris, Mark" <email@hidden>
> Cc: "email@hidden" <email@hidden>
> Subject: Re: EOEnterpriseObjectClazz with interface
>
> Hi Mark,
>
> have a look at BugTracker and its dependent framework BTBusinessLogic. That
> should you give some ideas. There are some more apps/frameworks in Wonder
> using that pattern, just have a look at the type hierarchy of the
> EOEnterpriseObjectClazz class (in Eclipse right click on the class name and
> select „Open Type Hierarchy“ from the context menu).
>
> jw
>
>
> Am 19.11.2018 um 06:31 schrieb Morris, Mark <email@hidden
> <mailto:email@hidden>>:
>
> Hi all,
>
> I ran into a simple case where a good old ObjC protocol would have worked
> fine, but Java provides only frustration. 😉
>
> I wanted to require that a class that decides to implement a particular
> interface should as part of that interface implement a certain static method.
> No go in Java.
>
> The implementing classes will always be subclasses of ERXGenericRecord, and a
> little searching uncovered the promising EOEnterpriseObjectsClazz approach.
> Right at the top it says:
>
> In Java, static methods are similar to class methods in Objective-C, but one
> cannot use static methods in interfaces and static methods cannot be
> overridden by a subclass. Using the clazz pattern removes those limitations.
>
> However, I didn’t see any examples of this use, and spent a little time but
> couldn’t figure it out. Are there any examples out there?
>
> Thanks!
> Mark
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