Package org.zkoss.zkex.ui.comet

Class CometServerPush

  • All Implemented Interfaces:
    org.zkoss.zk.ui.sys.ServerPush
    public class CometServerPush
extends java.lang.Object
implements org.zkoss.zk.ui.sys.ServerPush
    A server-push implementation that is based on comet. This implementation is compatible with any version of Servlet. It also means it doesn't utilize Servlet 3 asynchronous processing support. If you are using Servlet 3 servers, it is recommended to use CometServerPush instead.

    Available in ZK PE.

    Since:
    6.0.0
    Author:
    tomyeh

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      static interface  CometServerPush.AsyncInfo
      The interface for implementing asynchronous processing.
      protected static class  CometServerPush.ThreadInfo
      The info of a server-push thread.

    • Constructor Summary

      Constructors 
      Constructor Description
      CometServerPush()  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      boolean activate​(long timeout)  
      protected void beforeUpdate​(CometServerPush.ThreadInfo info)  
      boolean deactivate​(boolean stop)  
      org.zkoss.zk.ui.Desktop getDesktop()
      Returns the desktop that this server push belongs to (never null).
      protected int getIntPref​(java.lang.String key)
      Retrieve the integer preference by the given key.
      protected java.lang.String getStartScript()
      Returns the JavaScript codes to enable (a.k.a., start) the server push.
      protected java.lang.String getStartScript​(java.lang.String zkediton)  
      protected java.lang.String getStopScript()
      Returns the JavaScript codes to disable (a.k.a., stop) the server push.
      boolean isActive()  
      void onPiggyback()  
      protected void onStart()
      Called when start(org.zkoss.zk.ui.Desktop) is called.
      protected void onStop()
      Called when stop() is called.
      protected void processRequest​(org.zkoss.zk.ui.Execution exec, CometServerPush.AsyncInfo ai)
      Called when receiving the comet request from the client.
      void resume()
      ZK-1777 resume serverpush after DesktopRecycling
      <T extends org.zkoss.zk.ui.event.Event>
      void      		 schedule​(org.zkoss.zk.ui.event.EventListener<T> listener, T event, org.zkoss.zk.ui.sys.Scheduler<T> scheduler)  
      protected boolean setBusy()
      Sets busy and return if it is busy for processing other request.
      void start​(org.zkoss.zk.ui.Desktop desktop)
      Starts the server push.
      protected void startClientPush()
      Sends an AU response to the client to start the server push.
      void stop()
      Stops the server push.
      protected void stopClientPush()
      Sends an AU response the client to stop the server push.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Constructor Detail

      • CometServerPush

        public CometServerPush()

    • Method Detail

      • startClientPush

        protected void startClientPush()
        Sends an AU response to the client to start the server push. It is called by start(org.zkoss.zk.ui.Desktop).

        The derived class usually overrides this method to support different devices.

        The default implementation is to send an AuScript response to contain the script specified in a preference called CometServerPush.start, or the script returned by getStartScript(), if the preference is not found. Devices that don't support scripts could override this method to send a custom AU response (AuResponse).

      • stopClientPush

        protected void stopClientPush()
        Sends an AU response the client to stop the server push.

        The derived class usually overrides this method to support different devices, such as ZK Mobile.

        The default implementation is to send an AuScript instance to contain the script specified in a preference called CometServerPush.stop,' or the script returned by getStopScript(), if the preference is not found. Devices that don't support scripts could override this method to send a custom AU response (AuResponse).

      • getStartScript

        protected java.lang.String getStartScript()
        Returns the JavaScript codes to enable (a.k.a., start) the server push. It is called by startClientPush() to prepare the script of AuScript that will be sent to the client.

      • getStartScript

        protected java.lang.String getStartScript​(java.lang.String zkediton)

      • getIntPref

        protected int getIntPref​(java.lang.String key)
        Retrieve the integer preference by the given key. Visibility set to protected so that zkmax can have access to this method.

      • getStopScript

        protected java.lang.String getStopScript()
        Returns the JavaScript codes to disable (a.k.a., stop) the server push. It is called by stopClientPush() to prepare the script of AuScript that will be sent to the client.

      • getDesktop

        public org.zkoss.zk.ui.Desktop getDesktop()
        Returns the desktop that this server push belongs to (never null).

      • isActive

        public boolean isActive()
        Specified by:
        isActive in interface org.zkoss.zk.ui.sys.ServerPush

      • start

        public void start​(org.zkoss.zk.ui.Desktop desktop)
        Starts the server push.

        The derived class rarely need to override this method. Rather, override startClientPush().

        Specified by:
        start in interface org.zkoss.zk.ui.sys.ServerPush

      • resume

        public void resume()
        ZK-1777 resume serverpush after DesktopRecycling
        Specified by:
        resume in interface org.zkoss.zk.ui.sys.ServerPush

      • stop

        public void stop()
        Stops the server push.

        The derived class rarely need to override this method. Rather, override stopClientPush().

        Specified by:
        stop in interface org.zkoss.zk.ui.sys.ServerPush

      • onStart

        protected void onStart()
        Called when start(org.zkoss.zk.ui.Desktop) is called. This method is called before startClientPush(), and used to initialize the desktop, if necessary.

        The default implementation initializes an extension to process the comet request.

      • onStop

        protected void onStop()
        Called when stop() is called. This method is called after stopClientPush() is called and this server push has been cleaned up.

        The default implementation does nothing.

      • onPiggyback

        public void onPiggyback()
        Specified by:
        onPiggyback in interface org.zkoss.zk.ui.sys.ServerPush

      • schedule

        public <T extends org.zkoss.zk.ui.event.Event> void schedule​(org.zkoss.zk.ui.event.EventListener<T> listener,
                                                             T event,
                                                             org.zkoss.zk.ui.sys.Scheduler<T> scheduler)
        Specified by:
        schedule in interface org.zkoss.zk.ui.sys.ServerPush

      • setBusy

        protected boolean setBusy()
        Sets busy and return if it is busy for processing other request. If it is busy, true is returned. If it is not busy, false is returned but it is marked as busy.

        It is possible since the client might abort the previous one and issue a new one but their server didn't know.

      • processRequest

        protected void processRequest​(org.zkoss.zk.ui.Execution exec,
                              CometServerPush.AsyncInfo ai)
                       throws java.io.IOException
        Called when receiving the comet request from the client.
        Throws:
        java.io.IOException

      • activate

        public boolean activate​(long timeout)
                 throws java.lang.InterruptedException,
                        org.zkoss.zk.ui.DesktopUnavailableException
        Specified by:
        activate in interface org.zkoss.zk.ui.sys.ServerPush
        Throws:
        java.lang.InterruptedException
        org.zkoss.zk.ui.DesktopUnavailableException

      • deactivate

        public boolean deactivate​(boolean stop)
        Specified by:
        deactivate in interface org.zkoss.zk.ui.sys.ServerPush