code: public Object assignAggregateRoot(Object datamodel) {
  		modelProxyInjection.injectProperties(datamodel);
  		return modelAdvisor.createProxy(datamodel);
  	}
docs: assign a object as a AggregateRoot role, AggregateRoot can receive a
  command and reactive a event in CQRS.
  
  when we get a domain mode from repository with @introduce("modelcache")
  and @Around, the mode has been assign as a AggregateRoot;no need call
  this method.
  
  @param datamodel