[news.eclipse.tools.emf] Re: [newbie qns] reflection and class impl

[Ed Merks <merks@xxxxxxxxxx>]

Alex,

Comments below.


Tom Schindl wrote:
> Alex schrieb:
> > Hi,
> >
> > 1. is it possible to create an EClass through reflection? e.g. I have 
> > a class name as a string ("MyEClass"). Now I would like to create 
> > this class with the factory. The factory has a method "EObject 
> > create(EClass arg0)" but I don't know how to get the EClass from the 
> > string.
What else do you know about the name?  Something like 
EPackage.Registry.INSTANCE.getEPackage(<nsUR>).getEClassifier(<name>) 
will find the named classifier in the package.  Of course if you have 
the instance class or instance class name, Tom's advice is good.
> > 2. all our code is in a package seperated from the auto generated 
> > packages. If I define an operation in the ecore model (e.g. operation 
> > "myOperation" on the class "MyEClass") then I'm supposed to implement 
> > the method in the generated class "MyEClassImpl". But I would like to 
> > implement the operation in an own class (different package). Therefor 
> > I could extend the class "MyEClassImpl" but if I create this class 
> > through the factory then an object of type "MyEClassImpl" would be 
> > instantiated instead of my own implemention. Is there a good solution 
> > for this?
It's best to modify the generate MyEClassImpl directly; EMF supports 
merging when it regenerates, but you could also change the 
XyzFactoryImpl.createMyEClass method to return your Impl instead.  The 
problem I see is that anything that extends MyEClass will extend 
MyEClassImpl and not your class derived from it...
> > thanks a lot,
> > Alex
>
> I don't know if this the right thing but in my code (used to 
> instantiate classes for iBatis) I do something like this (I think it 
> was Ed's suggestion in a thread):
>
> > ((ExtendedSqlMapClient) sqlMap).getDelegate()
> >                     .setResultObjectFactory(new ResultObjectFactory() {
> >
> >                         @SuppressWarnings("unchecked")
> >                         public Object createInstance(String arg0, 
> > Class arg1)
> >                                 throws InstantiationException,
> >                                 IllegalAccessException {
> >
> >                             for (EClassifier cf : 
> > ingeniumPackage.eINSTANCE.getEClassifiers()) {
> >                                 if (cf.getInstanceClass() == arg1) {
> >                                     return EcoreUtil.create((EClass) 
> > cf);
> >                                 }
> >                             }
> >                             return null;
> >                         }
> >
> >                         public void setProperty(String arg0, String 
> > arg1) {
> >                         }
> >
> >                     });
If performance is important you might generate a map.  I suppose you 
could even make the constructors public (there's a generator flag for 
that) and just do newInstance...
> I have a class but you could easily exchange this with:
>
> cf.getInstanceClass().getName().equals("MyEClass").
>
> Tom