Patterns: Implementing Self-Service in an SOA Environment

246 Patterns: Implementing Self-Service in an SOA Environment

Note that a WML rendering kit is not a standard component of Rational

Software Architect at this time. However the JSF framework can clearly

accommodate this and other kits as they become available.

򐂰 JSF is a standard component of the J2EE 1.4 specification, and is rapidly

gaining acceptance in the industry. JSF is now supported by all major IDEs

and Web application servers, including the WebSphere and Rational family of

products.

JSF versus Struts

A fair question at this point, would be to ask why we selected the JSF framework

over Jakarta Struts? See 7.2.6, “Frameworks” on page 153 for more details

about Struts. It is true that there is no overwhelming advantage for JSF at this

time. The primary deciding factor was that JSF has now been adopted as a J2EE

standard. JSF has been embraced rapidly by the IT industry, including all the

major tool vendors. JSF incorporates most of the concepts which made Struts so

popular over the last few years, while making improvements in various areas.

The general consensus at this time, is that if an application is already

implemented in Struts, there is no great need to convert it to JSF. However,

when writing a new application, as we are in this case, JSF is the preferred

option.

Enterprise JavaBeans components

The last layer of our component model is composed of Enterprise JavaBeans

(EJBs), which provide the Model portion of the MVC pattern, as well as the

integration to the back-end services.

The Customer entity bean manages the data for one customer, storing it in a

DB2 table. Following the J2EE session facade pattern, the access to this entity

bean is encapsulated in an EJB session bean. The session facade also provides

access to the back-end services supporting the ITSOMart application.

9.2.3 Object model

This section describes the object model for the ITSOMart front-end, through the

use of various modeling diagrams.

Front-end class diagram

The class diagram in Figure 9-3 on page 247 shows the primary classes in the

ITSOMart front-end. For the sake of readability, we restricted the visibility of the

classes’ components strictly to those operations and data members we wanted

to highlight. Note that given the nature of a JSF front-end, a formal UML class

diagram might not provide the complete picture of the application. That is

because the JSP pages, which are an integral component of the JSF framework,

Chapter 9. JSF front-end scenario 247

are not allowed in standard UML class diagram notation. However we illustrate

the JSP relationships later in freeform diagrams, and Web flow diagrams.

Figure 9-3 ITSOMart front-end class diagram

The following are some of the key classes and relationships depicted in the class

diagram:

򐂰 The top portion of the diagram represents a layer of Java beans that support

the Faces JSP pages. There is a bean assigned to each JSP page, and each

bean is responsible for getting and setting the data in the JSF UI components

of the page. Some beans also support the action methods which trigger the

back-end requests. See 9.3.2, “JSF managed bean design” on page 257, for

an extended discussion about JSF managed beans.

򐂰 The CustomerDO class is the data object used to encapsulate and exchange

the customer information across the application.

PageCodeBase

<<

Java Class

>>

c

EmailValidator

<<

Java Class

>>

JSF Managed

Request Beans

DeleteConfirm

<<

Java Class

>>

SystemError

<<

Java Class

>>

CreateConfirm

<<

Java Class

>>

CustomerNotFound

<<

Java Class

>>

UpdateConfirm

<<

Java Class

>>

CustomerAdmin

<<

Java Class

>>

+ doLoginButtonAction ( )

CreateCustomer

<<Java Class>>

+ doCreateCustomerAction ( )

UpdateCustomer

<<

Java Class

>>

+ doUpdateCustomerAction ( )

+ doDeleteAction ( )

HomeFactory

<<

Java Class

>>

OrderSystemSessionFacadeLocal

LocalHome

<<

Java Interface

>>

OrderSystemSessionFacadeLocal

<<

Java Interface

>>

+ createCustomer ( )

+ retrieveCustomer ( )

+ updateCustomer ( )

+ deleteCustomer ( )

email : String

Iname : String

fname : String

streetAddress : String

city : String

phone : String

password : String

state : String

zip : String

accountInfo : String

deliveryType : String

CustomerDO

<<

Java Class

>>