Head:
	model=Model;

Model:
	ActivityModel | ComponentModel;

ActivityModel:
	activities+=Activity+
;

Activity:
	name=ID
;

ComponentModel:
	'Component' name=ID
	activities+=ComponentActivity+
;

ComponentActivity:
	name=ID ':'
	activityReference=[Activity]
;

MyActivity

Component system
a : MyActivity
b : MyActivity

	// Xtend code
	val resource = ???;
	val settings = EcoreUtil.UsageCrossReferencer.find(activity,
		resource);
	for (setting : settings) {
		if (setting.EObject instanceof ComponentActivity) {
			return setting.EObject.eContainer() as TranslationModel;
		}
	}

class MyDslGenerator extends AbstractGenerator {

	override void doGenerate(Resource resource, IFileSystemAccess2 fsa, IGeneratorContext context) {
		val model = (resource.allContents.head as Head).model
		if (model instanceof ActivityModel) {
			val activityModel = model as ActivityModel
			fsa.generateFile("Activities.txt", ActivityGenerator.generate(activityModel))
		}
	}
}

class ActivityGenerator {
	static def generate(ActivityModel activityModel) '''
	«FOR activity : activityModel.activities»
	Activity «activity.name» is referenced by «getReferenceCount(activity)» component activities.
	«ENDFOR»
	'''
	
	def static getReferenceCount(Activity activity) {
		// TODO: find the count of referencing component activities
		return 0;
	}
	
}

package org.xtext.example.mydsl.generator

import com.google.inject.Inject
import com.google.inject.Provider
import org.eclipse.core.runtime.NullProgressMonitor
import org.eclipse.emf.common.util.URI
import org.eclipse.emf.ecore.EObject
import org.eclipse.emf.ecore.EReference
import org.eclipse.emf.ecore.util.EcoreUtil
import org.eclipse.xtext.findReferences.IReferenceFinder
import org.eclipse.xtext.findReferences.IReferenceFinder.IResourceAccess
import org.eclipse.xtext.findReferences.TargetURIs
import org.eclipse.xtext.resource.IReferenceDescription
import org.eclipse.xtext.resource.IResourceDescriptions
import org.xtext.example.mydsl.myDsl.Activity
import org.xtext.example.mydsl.myDsl.ActivityModel

class ActivityGenerator {
	
	@Inject IReferenceFinder referenceFinder
	@Inject Provider<TargetURIs> targetURIProvider
	@Inject IResourceDescriptions resourceDescriptions
	
	def generate(ActivityModel activityModel) '''
		«FOR activity : activityModel.activities»
		Activity «activity.name» is referenced by «getReferenceCount(activity)» component activities.
		«ENDFOR»
	'''
	
	def getReferenceCount(Activity activity) {
		val acceptor = new MyDslReferenceAcceptor
		val uri = EcoreUtil.getURI(activity)
		val targetURIs = targetURIProvider.get
		targetURIs.addURI(uri)
		referenceFinder.findAllReferences(targetURIs, null, resourceDescriptions, acceptor, new NullProgressMonitor)
		return acceptor.count
	}
}

class MyDslReferenceAcceptor implements IReferenceFinder.Acceptor {
	
	int count = 0
	
	override accept(IReferenceDescription description) {
		count++
	}
	
	override accept(EObject source, URI sourceURI, EReference eReference, int index, EObject targetOrProxy, URI targetURI) {

	}
	
	def getCount() {
		count
	}
}

class MyDslGenerator extends AbstractGenerator {

	@Inject ActivityGenerator activityGenerator

	override void doGenerate(Resource resource, IFileSystemAccess2 fsa, IGeneratorContext context) {
		val model = (resource.allContents.head as Head).model
		if (model instanceof ActivityModel) {
			val activityModel = model as ActivityModel
			fsa.generateFile("Activities.txt", activityGenerator.generate(activityModel))
		}
	}
}

	static def generate(ActivityModel activityModel) '''
	«FOR activity : activityModel.activities»
	Activity «activity.name» is referenced by:
		«FOR pair : getReferenceCountPerComponent(activity)»
			«pair.value» activities in component '«pair.key.name»'
		«ENDFOR»
	«ENDFOR»
	'''

	def static List<Pair<ComponentModel, Integer>> getReferenceCountPerComponent(Activity activity) 
...