JSR 286 IPC with JSF

In case you are portlets developer, you know what JSR 286 is. It is the holy grail for the portlets which should enable the portlets to communicate with each others. At least you would think it is the holy grail, until you read the specs and look upon the Suns minimalistic examples.
It seems to me, this spec is out for it's own sake, and forwards the developers in the ice age of pure html, which is unthinkable for someone who has got used to API's such as JSF or Struts. Vendors as JBoss or ICEFaces have yet to deliver a bridge which will support JSR 286 with an AJAX push.

The sad news is that JSR 286 works only with out AJAX push, and you have to do some work around to get the grips of it in JSF Portal environment.

The first thing to do is to define the event you want to publish. This is done in the portlet.xml. There are three declaration there:

1. One Global declaration of your event
2. Supported publishing event for your pulbishing portlet
3. Supported processing event for our consumer portlet

The global event declaration looks as follow:

x:EventName
    java.lang.String

In the Publishing portlet, put the following:

x:EventName

And atlast, in the consumer portlet:

x:EventName

Now that you have configured your event that it is only a simple String, you should set it. This can be done in two way's:

1. Either extend javax.portlet.faces.GenericFacesPortlet and override the
   

   
   public void processAction(ActionRequest request, ActionResponse);
   

2. Or set the event in one of your Faces action methods.

If you prefer the first way, than you have to think that your to pass your full class name in the portlet.xml for portlet instantiation which would look like this:

org.mycomp.IPCPublisher

If you prefer the JSF action method way, than your portlet.xml will look as usual:

javax.portlet.faces.GenericFacesPortlet
  

In you decide to override the method of the GenericFacesPortlet, than you will set the event similar to this:

public void processAction(ActionRequest request, ActionResponse response)
throws PortletException,IOException {

   QName qname = new QName("http://www.mycomp.com/myevent" , "EventName");
   response.setEvent(qname, "Hallo IPC Communication.");
}

If you decide you would like to publish this event from inside of your JSF action method, you can do that as follow:

  public void publishIPCEvent(ActionEvent event){
   Object response = FacesContext.getCurrentInstance()
            .getExternalContext()
           .getResponse();

   if(response instanceof ActionResponse){
     ActionResponse aResponse = (ActionResponse)response;
      QName qname = new QName("http://www.mycomp.com/myevent" , "EventName");
        aResponse.setEvent(qname, "Hallo IPC Communication.");
    }
}

This method will be called as usual in JSF:

What is left is to read out this event in the Consumer portlet.
You should extend the Generic Faces Portlet and override the processEvent method. By doing that, don't forget to put the class definition in the portlet.xml as follow:

   org.mycomp.IPCConsumer

Override the method as follow:

public void processEvent(EventRequest request, EventResponse response) {
   Event event = request.getEvent();
   if(event.getName().equals("EventName")){
     String ipc = event.getValue();
     response.getPortletSession().setAttribute("ipc",ipc);
   }
}

As you can see, I read out the event and compare it's name if it is my event I want to handle. Than I read it's value and set it in the portlet session as attribute.

To get this value inside of JSF, you should do something like this:

 Object ipc = FacesContext.getCurrentInstance()
  .getExternalContext().getSession(false)
   .getAttribute("ipc);

Some say that one can annotate the certain method, which should be responsible for processing the event. This should look something like this:

@ProcessEvent(qname="{http://www.mycomp.com/myevent}EventName")
 public void myEventProcessingMethod(EventRequest request, EventResponse response){
    Event event = request.getEvent();
   if(event.getName().equals("EventName")){
     String ipc = event.getValue();
     response.getPortletSession().setAttribute("ipc",ipc);
   }
}

But this method annotation did not work for me inside of JSF. The same should work with java.util.HashMap instead of java.lang.String as well.

Anyways, this IPC approach is not that straightforward as some would like it to be, but it fullfils it's purpose.

Create your JSF componenst with out JSP or Facelets Tags

It is personal reference. Some love XML Syntax, some try to save them from the XML Jungle. JSF is a framework that allows you to create components dynamically. The JSF Tags are only option.

If you prefer to create your compnents without JSP or Facelets, and you don't want to envent the weel again, you can define your JSF Panel Grid in your JSP or Facelet as follow:

Define the bean in Spring config file as follow:

This bean holds a instance of the JSF HtmlPanelGrid which renders the JSF Panel Grid for you. The JSF components should be added to the Panel Grid with it's public method getChildren().add(Object o);. Here is the example:

package org.mypackage;

import javax.faces.application.Application;
import javax.faces.component.html.HtmlOutputText;
import javax.faces.component.html.HtmlPanelGrid;
import javax.faces.context.FacesContext;


public class MyBean {

private HtmlPanelGrid panelGrid;

public MyBean(){

}
public void init(){

Application application = FacesContext.getCurrentInstance().getApplication();
setPanelGrid((HtmlPanelGrid) application.createComponent(HtmlPanelGrid.COMPONENT_TYPE));

HtmlOutputText text = (HtmlOutputText) application.createComponent(HtmlOutputText.COMPONENT_TYPE);

text.setValue("Hallo JSF with out Tags.");

getPanelGrid().getChildren().add(text);

}
public void setPanelGrid(HtmlPanelGrid panelGrid) {
this.panelGrid = panelGrid;
}
public HtmlPanelGrid getPanelGrid() {
return panelGrid;
}

}

1. In line 16 is the public method which will be ivoked by Spring after instantiation of the Bean.
2. Line 18 gets an instance of the current application.
3. On line 19 we create an instance of HtmlOutputText with the help of the method createComponent which takes String as argument. Every JSF Component defines public static field COMPONENT_TYPE which returns the type of the component to be created.
4. On line 21 a instance of HtmlOutputText is created in the same way as the HtmlOutputText.
5. In line 23 we set the value of the output text.
6. In line 25 we set the output text component as child of the Panel Grid.

On the end of the day, when JSF try's to render the Panel Grid with the ID dynamic in the JSP or Facelets, the Property panelGrid of the backing bean will be called and our instance would be copied and rendered.

In this way, we can create whole views or parts of it, as if we program in pure Java.

Basic RichFaces Project with Spring

To create basic RichFaces enabled project, you can run the following maven command provided by JBoss.

mvn archetype:generate
-DarchetypeGroupId=org.jboss.portletbridge.archetypes
-DarchetypeArtifactId=richfaces-basic
-DarchetypeVersion=1.0.0.B6
-DgroupId=org.whatever.project
-DartifactId=myprojectname
-DarchetypeRepository=http://repository.jboss.org/maven2/

Make sure that you use the proper version of the Portlet Bridge of Jboss. Read more here
To enable Spring to manage your JSF Beans you should add this context arguments to your web.xml

  
    org.springframework.web.context.ContextLoaderListener
  



  
   org.springframework.web.context.request.RequestContextListener
  

This are the listeners which enables Spring to load it's context and create the beans, and to process Request from JSF to Spring and preserve the session.

Inside of faces-config.xml :

          org.springframework.web.jsf.DelegatingVariableResolver
    

This delegates the JSF Variable resolver to look up for EL Expressions defined beans in Spring. In other words, it replaces the standard JSF EL resolver.

Now you would be able to define your JSF Beans in Spring as follows:

 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:osgi="http://www.springframework.org/schema/osgi"
 xsi:schemaLocation="http://www.springframework.org/schema/beans   
       http://www.springframework.org/schema/beans/spring-beans.xsd">
       
       
       
   

This bean can be used with your JSF Tag as usual:

In deed simple.

Here is the full web.xml:

                xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

 
   javax.faces.STATE_SAVING_METHOD
   server
 


   
      javax.portlet.faces.renderPolicy
      ALWAYS_DELEGATE
   

   
      org.ajax4jsf.RESOURCE_URI_PREFIX
      rfRes
   

   
      org.richfaces.LoadStyleStrategy
      NONE
   
   
      
      org.richfaces.LoadScriptStrategy
      NONE
   

   
      org.ajax4jsf.COMPRESS_SCRIPT
      true
   


      org.richfaces.CONTROL_SKINNING
      enable


 
  contextConfigLocation
  classpath:spring-context.xml
 

     
  RichFaces Filter 
   richfaces   
   org.ajax4jsf.Filter 
 

       
   richfaces 
   Faces Servlet
   REQUEST
   FORWARD
   INCLUDE

  

   com.sun.faces.config.ConfigureListener
  
 
 
  org.springframework.web.context.ContextLoaderListener
 
 
 
  org.springframework.web.context.request.RequestContextListener
 
 



   Faces Servlet
   javax.faces.webapp.FacesServlet
   1




   Faces Servlet
   /faces/*


   Faces Servlet
   *.jsf


   
      FacesServlet
      *.mk
   


 
  10
 
 
 
  Restrict access to JSP pages
  
   Restrict access to JSP pages
     
  
  
   With no roles defined, no access granted
  
 
 
  BASIC