RE: OSGi Support

From: Freire, Jose Luis \(PT - Lisbon\) <"Freire,>
Date: Mon, 7 Apr 2008 21:58:46 +0100

Hi Jason,


I'm glad you asked!


According to the experts there are two ways of making web applications work in OSGI.


We could run the OSGI container inside an application server, or run the application server as a bundle inside a OSGI container (the recommend way by the people)


So, the OSGI container would bootstrap the existing bundles:

1) The application server (like tomcat, jetty, etc)

2) The Mojarra bundle (javax.faces)

3) The web application bundles


OSGI (version 4.1, April 2007) already has a HTTP Service Specifications so JSF would have to register itself in the HTTP service.


The application bundles would register themselves as resources using the Http Service or some kind of special Mojarra extension point.


I'll try to use an example to illustrate how I envision a JSF OSGI application.


Suppose we're building an application that has a core bundle called com.mycompany with the following files:



+ index.xhtml


+ faces-config.xml







The plugin.xml file would:

1) Register the "/WebContent" folder to the HTTP context "/myapp"

2) Register the com.mycompany.Menu extension point, that would be handled by the


The faces-config.xml would declare the as a backend bean named "menu".


MenuBean would have a method "public List<MenuItem> getItems()" that would read the "com.mycompany.Menu" extension and return the list of MenuItem objects with the String properties: navigationRule and title.


Index.xtml would be something like:


<c:forEach items="#{menu.items}" var="item">

                <h:commandLink action="#{item.navigationRule}" value="#{item.title}" />



If we run the OSGi container at this point, the application (http:/myhost/myapp/index.xhtml) would do nothing because no one is attaching to the com.mycompany.Menu extension.


So we add the "Clients" plugin.


The bundle called com.mycompany.clients would have the following files:


+ clientList.xhtml

+ clientEdit.xhtml


                + faces-config.xml





+ plugin.xml


The plugin.xml file would

1) Register "/WebContent" folder to the Http context "/myapp/clients"

2) Attach to the com.mycompany.Menu extension point with, that would add a MenuItem object with "Clients" as title and "goToClientList" as navigation rule


The faces-config.xml would

1) Declare the as a backend bean for use with clientList.xhtml and clientEdit.xhtml

2) Declare the navigation rule "goToClientList" to go to /myapp/clients/clientList.xhtml


If we run the OSGI container again we would see a page with a link named "Clients", and if we click it, we would go to "http://myhost/myapp/clients/clientList.xhtml"



1) The inner workings of JSF wouldn't change because we would continue to use faces-config.xml to define each JSF bundle (managed beans, navigation rules, etc)

2) We would have to tell JSF which resources are attached to the JSF servlet by using the Http Resource service, or by a javax.faces.resource extension point.


We could go crazy and have some other extensions points like javax.faces.validator to declare validators, but I don't think it would bring any immediate benefit.




José Freire
Consulting - Financial Services Industry
Deloitte & Touche, Quality Firm, S.A.

Main: +(351) 21 042 25 00
Fax: +(351) 21 042 29 50

Edifício Atrium Saldanha
Praça Duque de Saldanha, 1 - 7º
1050-094 Lisboa

From: Jason Lee []
Sent: segunda-feira, 7 de Abril de 2008 19:43
To: Dev - JSF
Subject: OSGi Support


Recently....someone :) inquired about making JSF, meaning Mojarra, I assume, OSGi compliant, a suggestion in which Ed expressed a high degree of interest. If this were done, what exactly would/should that look like? I'll admit that I'm extremely new to OSGi, so maybe my nascent knowledge is the real hindrance here. Would we, say, package the ViewHandler as an OSGi bundle, allowing it to be swapped out at runtime? Would the Servlet ContextListener (and it's counterpart in the Portlet world) be responsible for starting the OSGi container? Do my questions even make sense? :)

I'm trying to come up to speed on OSGi due to an unrelated impetus, but this user's question keeps running through my mind, so I'm wondering if anyone else has given it some concrete thought and has a better understanding of OSGi to help clear the air a bit. :)

Jason Lee, SCJP
Software Architect -- Objectstream, Inc.
Mojarra and Mojarra Scales Dev Team 
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