Notify enduser when #Async annotated method finished with out using p:poll - multithreading

Question

How to notify with a listener when the Future method has finished using #Async annotation in spring based service layer and with a thread pool in application context called from a ManagedBean . I have tried with p:poll listener with a listener method future.isDone() but is not very effective because it makes many requests to the server.
Edit.
here is the example
#ManagedBean
#ViewScoped
public class Controller
{
Future<SomeModel> someFuture;
#ManagedProperty(value = "#{someService}")
private SomeService someService;
private String things;
private SomeModel someModel;
private boolean renderSomeModel;
public void callAsyncMethod()
{
someFuture = someService.thingsToBeInsered(things);
//here make the poll in jsf start
}
public void methodAsyncFinished{
if(someFuture!=null)
{
if(this.someFuture.isDone())
{
renderSomeModel = true;
//here make the poll to stop
}
}
}
#Service
public class SomeService
{
#Async
Future<SomeModel> thingsToBeInsered(things)
{
//Calling the dao here
return new AsyncResult<SomeModel>(things);
}
}
//spring context
<task:annotation-driven executor="taskExecutor" proxy-target-class="true"/>
<bean id="taskExecutor"
class="org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor">
<property name="corePoolSize" value="${thread_pool.corePoolSize}" />
<property name="maxPoolSize" value="${thread_pool.maxPoolSize}" />
<property name="WaitForTasksToCompleteOnShutdown" value="${thread_pool.waitForTasksToCompleteOnShutdown}" />
</bean>
jsf
<p:poll autoStart="false" widgetVar="asyncGenPoll" interval="6" listener="#{controller.methodAsyncFinished}" update="resultPanel"/>