Page 110 - DCAP308_OBJECT_ORIENTED_ANALYSIS_AND_DESIGN

Object Oriented Analysis and Design

Notes

Case Study Answering System

The Answering System is system foe answering phone calls and recording messages from
callers. It is intended as a personal answering system for a single owner. It will support:

Modes for announce only and accepting caller messages
Ability to review caller messages
Personalized greetings
Local management of modes, greetings, and caller messages
Answering System Domain Use Case Model
Let us analyze the requirement document to identify the potential actors and use cases of
the system. First, let’s list the potential actors. A quick look at requirement document
shows the following terms and entities specific to the system:
The caller is the person who is answered and their messages are taken
The owner is person who records the greetings, set the answer mode and reviews
the caller me
Identifying Actor
There are certain terms and entities in the list that identify that they perform certain roles
or business processes. From the preceding list, we can see that there are some entities that
perform an action and some that form the target for the action. The entities that perform
action will be the actor for Answering System. In the above list, the actor that we can
identify are:
Owner
Caller
Identifying Use Cases
Next, let’s identify the potential business processes in the Answering System. The primary
business flows in the system are:
Review Caller Messages
Answer Caller
Set Answer Mode
Record Greetings
As we analyze the requirement document further, we can determine some discrete processes
within these primary business flows. To review caller messages, the owner needs to have
ability to delete caller message. So, within the “Review Caller Messages” use case, we can
identify following use case:

Delete Caller Message
The “Answer Caller” use case can be refined into smaller discrete processes such as play
greeting, take caller message. Now, the use cases that we identified within the “Answer
Caller” are:

Play Greeting
Take Caller Message
Contd...

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