@Override
 public void afterPropertiesSet() throws Exception {
   if (parameterResolverFactory == null) {
     parameterResolverFactory =
         AnnotationConfiguration.readFor(aggregateType).getParameterResolverFactory();
   }
   handler =
       new AggregateAnnotationCommandHandler<T>(
           aggregateType, repository, commandTargetResolver, parameterResolverFactory);
   for (String cmd : handler.supportedCommands()) {
     commandBus.subscribe(cmd, handler);
   }
 }