JBoss Seam : Stitching JSF and EJB3
|Open source, and developed under the auspices of JBoss, Seam is a component framework that focuses to deliver full-featured JEE 5 applications in a lightweight code base i.e. requiring only a fraction of the code of regular JEE applications.
JBoss Seam is a robust JEE 5 framework that replaces the traditional way to develop the applications with some clever architecture and techniques. With Seam, JEE 5 and EJB3, seems
to go a long way with their focus on the lightweight Java support and reducing the code bloat issues, which has been haunting the developers for a long time.
Although the specifications for JEE 5 are still not yet finalized, there is already a ramework available. Seam being built on top of JEE 5 and EJB3 tries to further reduce the code required to build a functional application. Seam tries to put the new design patterns to resolve out the evergreen problems that haunt the development of the J2EE 1.4 applications,especially those concerned with the web-based user interface and demanding the EJBs at the back-end. This required a lot of tedious coding.Though most of the IDE tools tries to reduce the the developer’s role in the code generation especially while coding the EJB interfaces and the required helper classes, still the developer faces the huge code base to manage and maintain.
Let’s give a quick glance to the J2EE application development, and see how JBoss Seam proves to be a natural progression beyond JEE 5.
The classic framework
To get familiar with the functionality of the JBoss Seam, it is vital to overview the role of the classic application framework, which orients around the two distinct phases:
1 creation of the user interface
2 creation of the application logic
Together with JEE 5, JBoss Seam attempts to simplify these two phases. Always the
business logic code is required to the develop the code individually and it cann’t be automated. Though, most of the application’s tedious code orients around creating the UI to handle the user interactions and to provide the support for the code to arrange data back and forth between UI components and the application components. Seam has made a superb attempt to eliminate the bulkiness of such required codes. Figure 1 illustrates the classic
framework. Much of this classic architecture still applies today – even to JEE 5 and JBoss Seam.
Figure 1: The classic framework
Figure 1 depicts the classic UI framework along with the application flow. The UI framework
provides the components that allows the developers to easily create and maintain a layout
in their initialization code. At the runtime, this UI framework constructs the GUIs out of these components, and allows the user to interact with the system. At well-defined points of the user
interaction, events are fired from the application components. Being an application developer, you just need to write the code to handle these events. This is sometimes referred as the “events-driven programming”.
Java Server Faces and JEE 5
Officially sun is going to include Java Server Faces (JSF) as its built-in UI framework with the release of its upcoming JEE 5 specifications. JSF has implemented the classic UI features as its UI framework architecture to meet the presentation purpose. However it needs to
Nov 2007 | Java Jazz Up | 16
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