Guice error when trying to use Alf Xtext parser as Standalone - eclipse

Question

I am trying to write a plugin for Papyrus that converts Alf code.
I tried to use the Alf-parser that is already included in Papyrus (org.eclipse.papyrus.uml.alf.*). So I tried to instantiate the parser as written here:
public class Activator extends Plugin {
// default Activator code here ...
public String ConvertAlfToSpecSharp(String alf)
{
new org.eclipse.emf.mwe.utils.StandaloneSetup().setPlatformUri("../");
Injector injector = new AlfStandaloneSetup().createInjectorAndDoEMFRegistration();
XtextResourceSet resourceSet = injector.getInstance(XtextResourceSet.class);
resourceSet.addLoadOption(XtextResource.OPTION_RESOLVE_ALL, Boolean.TRUE);
// ...
}
}
But the first line (new org.eclipse.emf.mwe.utils.StandaloneSetup().setPlatformUri("../");) throws the following exception:
com.google.inject.CreationException: Guice creation errors:
1) Error injecting method, java.lang.IllegalStateException: No EPackages were registered for the validator org.eclipse.papyrus.uml.alf.validation.CommonJavaValidator please override and implement getEPackages().
at org.eclipse.xtext.validation.AbstractInjectableValidator.register(Unknown Source)
at org.eclipse.xtext.service.MethodBasedModule.configure(MethodBasedModule.java:55)
while locating org.eclipse.papyrus.uml.alf.validation.CommonJavaValidator
1 error
at com.google.inject.internal.Errors.throwCreationExceptionIfErrorsExist(Errors.java:435)
at com.google.inject.internal.InternalInjectorCreator.injectDynamically(InternalInjectorCreator.java:183)
at com.google.inject.internal.InternalInjectorCreator.build(InternalInjectorCreator.java:109)
at com.google.inject.Guice.createInjector(Guice.java:95)
at com.google.inject.Guice.createInjector(Guice.java:72)
at com.google.inject.Guice.createInjector(Guice.java:62)
at org.eclipse.papyrus.uml.alf.CommonStandaloneSetupGenerated.createInjector(CommonStandaloneSetupGenerated.java:28)
at org.eclipse.papyrus.uml.alf.CommonStandaloneSetupGenerated.createInjectorAndDoEMFRegistration(CommonStandaloneSetupGenerated.java:22)
at org.eclipse.papyrus.uml.alf.CommonStandaloneSetup.doSetup(CommonStandaloneSetup.java:23)
at org.eclipse.papyrus.uml.alf.AlfStandaloneSetupGenerated.createInjectorAndDoEMFRegistration(AlfStandaloneSetupGenerated.java:20)
at <packagenamehere>.Activator.ConvertAlfToSpecSharp(Activator.java:113)
I have no idea how to solve this, especially since I find it very hard to debug eclipse applications...
Update:
Here are links to some relevant classes (all from the org.eclipse.papyrus.uml.alf.common plugin of Papyrus plugins (link)):
org.eclipse.papyrus.uml.alf.CommonStandaloneSetup
org.eclipse.papyrus.uml.alf.CommonStandaloneSetupGenerated
org.eclipse.papyrus.uml.alf.validation.CommonJavaValidator
org.eclipse.papyrus.uml.alf.validation.AbstractCommonJavaValidator

Answer 1

As you can see, the method getEPackages() of AbstractCommonJavaValidator.java returns an empty list.
If you look at this AbstractAlfJavaValidator implementation, there is an EPackage which is added to the list.
As a solution, i think you should edit CommonJavaValidator.java and override getEPackages() in order to add an EPackage:
#Override
protected List<EPackage> getEPackages() {
List<EPackage> result = super.getEPackages();
// result.add(org.eclipse.papyrus.uml.alf.alf.AlfPackage.eINSTANCE);
// Edit
result.add(org.eclipse.emf.ecore.EcorePackage.eINSTANCE);
return result;
}
Edit
If you can't edit papyrus plugins, it think you should add the following before your code:
if (!EPackage.Registry.INSTANCE.containsKey("http://www.eclipse.org/papyrus/alf/Alf")) {
EPackage.Registry.INSTANCE.put("http://www.eclipse.org/papyrus/alf/Alf", org.eclipse.papyrus.uml.alf.alf.AlfPackage.eINSTANCE);
}
It will add an EPackage before the guice creation and the exception will avoided.