new ThreadLocal<HashMap<String, EntityManager>>();
public Object execute(InvocationContext invocationContext) throws Exception
{
Transactional transactionalAnnotation = extractTransactionalAnnotation(invocationContext);
Class<? extends Annotation> qualifierClass = getTransactionQualifier(transactionalAnnotation);
String qualifierKey = qualifierClass.getName();
// the 'layer' of the transactional invocation, aka the refCounter for the current qualifier