Polling – sending periodical AJAX requests
Polling is a way to poll a server periodically in order to trigger some server-side changes or update parts of a web page. The polling technology in PrimeFaces is represented by the Poll component. It is an AJAX component that has an ability to send periodical AJAX requests.
In this recipe, we will update a feed reader periodically to show current sports news. A Growl component will be updated with the same interval too, in order to show the time of the last feed update.
How to do it...
The p:poll component in the following code snippet invokes the listener method showMessage() every 10 seconds and updates a feed reader and growl. The listener method generates the current time. Furthermore, we will define a widget
variable in order to stop or start polling, using the client-side API. This occurs via command buttons.
<p:growl id="growl"/>
<p:poll id="poll" listener="#{pollingController.showMessage}"
update="sportFeed growl" interval...
