Get list of all EAttribute Types

[glsp-bot]

I'm working on issue #37 and wont to get a list of all possible EAttribute Types from ecore.
After quite some time of looking and googleing I can't find any function which would return me all possible Types.
Anyone knows where to look?

original thread by Leo Knoll

[CamilleLetavernier]

The simplest (low-level) solution would be to iterate on EcorePackage.eINSTANCE.getClassifiers() (For predefined Ecore EClassifiers, like EString or EInt) and on resourceSet/resources/getAllContents() to find all local EClassifiers in the current model.

However, the plug-in org.eclipse.emf.ecore.edit should contain a list of (auto-generated) adapters covering this use case (e.g. org.eclipse.emf.edit.provider.IItemPropertyDescriptor.getChoiceOfValues(Object))

It's not easy to navigate in these classes, let me see if I can find a small example

[CamilleLetavernier]

Here's an example for retrieving the possible super types of an EClass. It works in a similar way for any reference (Including EAttribute#EType). Note that you'll need to add a dependency to org.eclipse.emf.ecore.edit on the server side, as it's currently not included.
Also, the resulting list might need to be filtered a little bit, but you'll see when you get there :)

```private Collection<?> getPossibleSupertypes(EClass eClass){
    AdapterFactory factory = getAdapterFactory(eClass);
    IItemPropertySource itemPropertySource = (IItemPropertySource)factory.adapt(eClass, IItemPropertySource.class);
    IItemPropertyDescriptor itemPropertyDescriptor = itemPropertySource.getPropertyDescriptor(eClass, EcorePackage.Literals.ECLASS__ESUPER_TYPES);
    Collection<?> choiceOfValues = new ArrayList<>(itemPropertyDescriptor.getChoiceOfValues(eClass));
    return choiceOfValues;
}

private AdapterFactory getAdapterFactory(EObject attr) {
    return new EcoreItemProviderAdapterFactory();
}```

I've simplified the code for readability, but the Adapter Factory should be created only once, as it's quite expensive

[glsp-bot]

[Leo Knoll]

Thank you for the answer!
It seems to be more complicated then I thought...
The only other solution I though of is to use Reflection on EcorePackage.eINSTANCE and check for return Type 'EDataType' but this is probably less clean.

[eneufeld]

As Camille pointed out the cleanest solution would be to use the method he provided, the problem is that you would pull in many dependencies as emf.edit is depending on org.eclipse.ui .
I think it is sufficient to get the predefined types as described by Camille using EcorePackage.eINSTANCE.getClassifiers() and add all EClassifiers of your resource which are of type EDataType or EEnum

[CamilleLetavernier]

As Camille pointed out the cleanest solution would be to use the method he provided, the problem is that you would pull in many dependencies as emf.edit is depending on org.eclipse.ui .

You scared me for a second, so I checked again, and it doesn't :) It only depends on eclipse.core.runtime and eclipse.core.resources, and even these dependencies are optional

[eneufeld]

Sorry, I mixed it up with the org.eclipse.emf.edit.ui bundle

[glsp-bot]

[Leo Knoll]

https://spectrum.imgix.net/threads/052c185c-5972-4be9-ab8d-597f2f6d77b9/d60797fb-6197-45a8-abaf-b782a2b8adb0-Capture1000.PNG?expires=1629331200000&ixlib=js-1.3.0&s=9df870124a9b8bdc5d547db9d2077dad

[glsp-bot]

[Leo Knoll]

Thank you for the tips, I decided to use the simple approach suggested, here is my solution.

[CamilleLetavernier]

Be careful: all lists in EMF are returned by reference. So if you add elements to an existing EList, it will actually modify the underlying model

[CamilleLetavernier]

To aggregate the results of EcorePackage EDataTypes and the EDataTypes from the current resource, you should start by creating a copy of the listOfTypes, and only add elements to this copy

[glsp-bot]

[Leo Knoll]

Good point, I made sure to copy it first now! :-)

[eneufeld]

@leo-knoll I have some question about your code:

1. why do you do EcorePackage.eInstance.getEclassifier().eContainer().eContents(); ? why not simply use EcorePackage.eInstance.getEclassifier() ?

2. what is the ResourceManager, where is it coming from?

3. you need to check for EDataType and EEnum in both lists

[CamilleLetavernier]

what is the ResourceManager, where is it coming from?

ResourceManager is a service from the GLSP Ecore Server, which is responsible for loading the model (Initializing the ResourceSet, etc)

[glsp-bot]

[Leo Knoll]

@eneufeld

1. EcorePackage.eINSTANCE.getEClassifier() returns an EClass, not sure how I get a list of potential attribute types except with `.eContainer().eContents()``

2. as @camille-letavernier said I need it to read the ResourceSet, I get it through the current GraphicalModelState EcoreModelState.getResourceManager(graphicalModelState)

3. EEnum inherits from EDataType, but I'll add a check for EDataType.

[CamilleLetavernier]

EcorePackage.eINSTANCE.getEClassifier() returns an EClass, not sure how I get a list of potential attribute types except with `.eContainer().eContents()``

I think Eugen meant 'EcorePackage.eINSTANCE.getEClassifiers()', which returns a List of EClassifiers :)

EEnum inherits from EDataType, but I'll add a check for EDataType.

+1

[glsp-bot]

[Leo Knoll]

I see that makes more sense :D
Alright I think the function is perfect now ;-)