212 WebSphere Application Server - Express V6 Developers Guide and Development Examples
5.2 Requirements
Several new requirements have been introduced for this version of the
application. These include:
򐂰 A bidding system
򐂰 Search the property catalog with a Web services
򐂰 Notification of the addition or modification of a news item with a Web service
򐂰 User maintenance with a Message Driven Bean (MDB)
򐂰 Implementation of the news system using JavaServer Faces(JSF)
򐂰 New functionality will be created to manage reference data
The bidding system is the only new component. The other new requirements
expose existing functionality using different technologies.
5.2.1 Bidding system
The bidding system will allow users to bid on properties. The bidding system will
work this way:
򐂰 To keep our requirement simple, we will allow only one outstanding, or open,
bid on a property. A property may have more than one bid, but all bids except
one will be in the rejected state. The last remaining bid will be in either the
open state or the accepted state. Potentially, all bids can be in the rejected
state. A user cannot place a bid on a property if that property has an open bid
or an accepted bid. A result of this simplification is that only the latest
chronological bid can be open or accepted.
򐂰 Sellers will be allowed to see the bids on the property and accept or reject the
open bid. All of the bids that have been placed on a property are referred to
as the
bid history. The agent selling the property and administrators will be
allowed to see the bid history but will not be allowed to accept or reject a bid.
When a bid is displayed to any user, both the bid amount and the bid state are
򐂰 A bidder will be allowed to only view their bids. The bidder can have placed
multiple bids on a property that have been rejected. Thus, a bidder is shown
his or her own filtered view of the bid history.
򐂰 Nonlogged-in users cannot place bids or see any bidding history.
򐂰 Only properties that are in the active status can be bid upon. When a bid is
accepted, the property status is updated to sold.
򐂰 The system will restrict the seller, or the agent selling the property, from
bidding on the property.
򐂰 Nonrequirements are as follows:
Chapter 5. Requirements 213
It is not a requirement that an accepted bid be of a greater amount than
any rejected bid.
Notifications to any bidder, seller, or agent when a bid is placed, accepted
or rejected are also not required.
5.2.2 Catalog search and news feed Web services
A Web service interface will be provided to allow users to obtain a list of
properties that match a input search criteria.
A Web service interface will be provided to allow users to add and list news
5.2.3 User maintenance with Java Message Service
A Java Message Service(JMS) interface will be provided to the User
management component. This will allow users to be created or modified upon
receipt of a JMS message.
Whenever a user is added or modified by the Web application, an output JMS
message will be created.
5.2.4 Use JavaServer Faces for the news component
This requirement allows us to replace the Struts view and controller functions in
the News component with a JavaServer Faces implementation. The purpose is
to investigate JSF technology and become familiar with the JSF tools provided
by Rational Web Developer.
We also compare a JSF and SDO implementation of the news component with a
JSF implementation that reuses our existing data access layer.
5.2.5 Reference data component
Nearly all applications have the concept of reference data. Reference data can
be lists of user titles (Mr., Mrs., Miss) or country codes. Statuses are also
typically reference data as are items such as user roles (Administrator,
Customer, Agent, and so on).
The reference data component will be implemented just as any other component.
Even though it is stateless, the manager will still be wrapped by a session data
class. This follows the application architecture and design principles.

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