Thursday, February 21, 2008

The Next BIG thing ADF Faces: Getting the comfort level in comparison to OAF.

Hi all.... starting with new interesting article... after I have returned from my Vaishnodevi Trip!I was thinking of writing this article from quite a some time, but was busy with various things, as I recently moved back to Delhi!

Ok, I think lets' start, as we all know Oracle Fusion techstack includes ADF faces for all web related development, I think this is the best time to optimize your skillset to ADF faces and Bpel.ADF is an extensive J2EE framework, which is
documented as well as used for two category of programmers:

1)Developers from J2EE background,i.e. people having knowldge of JSF,STRUTS,JAVASCRIPT,SWING,TOPLINKS,EJBs etc,

2)Developers from Forms background,i.e. the best suited guys are the OAF guys, who already have exposure to BC4J.Basically this category of developers, as they work on this framework, they gradually learn more and more standard J2EE technologies gradually.

In this article, I have typically covered approach for OAF developers, who I assume have a good exposure to core Java and BC4J, but have not worked/have knowledge of toplinks, ejbs',struts etc.

Here is the list of downloads, you would need to have to start with ADF Faces on your laptop/computer:

1)JDEVELOPER 10G (Download Oracle JDeveloper (
Oracle JDeveloper(

2)ADF Faces guide for forms developers (Download Developer's Guide for Forms/4GL Developers pdf version)
Download Developer's Guide for Forms/4GL Developers

3)Database server(This you would require to download, if you don't have a database server, and your working on your home pc/laptop.Download Oracle Database 10g Express Edition (Western European) )
Oracle Database 10g Express Edition

Similarities between OAF and ADF
Both OAF and ADF follow industry best pratices i.e. MVC standard(Model-View-Controller), for people who still don't have a fundamental understanding of MVC, i would suggest reading:
Article On Web-Tier Application Framework Design
Here are MVC layers of both:

Model : All BC4J Component classes like AM,EO,VO,VL etc.
View : UIX
Controller : CO classes.

Model : All BC4J Component classes like AM,EO,VO,VL etc.
View : JSF JSPs, in simple terms file with extension .jspx
Controller : Backing bean classes.

As we see above Model layer is same for both i.e. BC4J, hence OAF developers, have a added advantage since, working with OAF, they already have sound knowledge of this. Next comes the view layer thats changed from UIX to JSF.One major problem with UIX in OAF is that UI is not very extensive, in the sense that there are many limitations on UI front , while if you take JSF, its a Sun's standard j2ee technology where you can have all web features integrated and is also flexible enough to integrate UIs from other technologies.... like industry popular Flex, flash etc.Jsf is capable enough to deliver most complex and extensive UIs.

Now, as in OAF,most of the UI development is done through drag and drop and wizards in Jdeveloper(Or even if the page is dynamic you would write java code for adding various UIX beans to pagelayout region), hence, even if you don't have any knowledge/limited knowledge of xml and UIX, then also you can work with ease,because Jdeveloper generates the xml for you.The same is in the case of ADF, most(not all) UI development is done through wizards and drag-drop functionality in Jdeveloper.You only need to have bean level knowledge, similar to OAF.

The last layer, i.e. the controller layer is quite similar to what we code in CO classes in OAF, typically every page where you need to put event logic, you would need to attach a backing bean class to that jspx page. This can be automatically done through wizard in Jdeveloper.The backing bean class typically contain getter/setter methods of all beans in the page, so you can add your custom event methods to this class which will be attached to UI through EL.

I think by now you would have developed some comfort level with ADF! One stunning feature of ADF are the flow diagrams, like in OAF to redirect to diffent page you use vaious page forward apis' in pageContext class.In ADF, you can design the whole flow in flow-diagram, which is a completely drag and drop feature of Jdeveloper ad then attach it with action of any bean say a "command button", on whose submission you want to redirect the flow.

To start with example, Oracle provides a fantastic tutorial called SRDEMO. You can run it on your Jdev, read the guide and get aquittaned with ADF.

Recently, there was a discussion on "OAF Forum" regarding "Can ADF Faces/ADF BC aplications developed on Jdeveloper 10g can be deployed on Apps 11i?".
Here is the Steven Chan's blog comments link which gives you the answer:
Read last question on this link.

He basically says "The E-Business Suite uses Oracle9i Application Server as its application tier server. You cannot use this to run externally-developed applications.

I would recommend running your custom application on an external Oracle Application Server 10g instance.

Another point is pointed by Tapash for Apache Jserv application server used in Oracle Apps 11i, he says "Apache JServ module , QApache are servers built at oracle not totally open sourced, so these are not pure J2EE servers, although you can run some J2EE components like jsps/servlets/EJBs, but these servers dont have containers for all J2EE components.". So, i would say Apache name is misleading, because things immediately flicks my mind saying open source :)!

Hence, for Apps 11i version ADF faces can't be atleast in straight forward way be deployed. If you are using Apps 11i version , you should use external J2ee compliant server, like Apache Tomcat,OC4J etc. for hosting your ADF Faces/ ADF BC application.
This is not the case with Apps R12, which is a j2ee compliant server, hence you can deploy all ur ADF faces applications on the same application server.This is because of the fact Oracle has moved to OC4J application server with R12.

I hope I am able to give some picture of vast ADF to OAF developer community through this article!I will soon write another article of making a sample page in ADF and integrating it with OAF/JTT/JTF pages in Apps.