The server-push-class Element

[Optional][Default: depends on device and what edition you use]

It specifies which class used to implement the server-push feature. The class must have a default constructor (without any argument), and implement the ServerPush interface.

 <device-config>
     <device-type>ajax</device-type>
     <server-push-class>my.ServerPush</server-push-class>
 </device-config>

In addition to configuring the application's default implementation, you can choose an implement for a particular class by use of DesktopCtrl.enableServerPush(ServerPush). For example,

((DesktopCtrl)desktop).enableServerPush(new org.zkoss.zk.ui.impl.PollingServerPush());