BASIC AND ALTERNATE FLOWS IN USE CASE SPECIFICATION
A USE CASE represents Business Goal. USE CASE is a Textual description that captures User and System interaction. USE CASE illustrates the activities that are performed by users of the system, hence, it is a scenario-based technique in the UML.
As a Business Analyst, we use this as a communication tool to bridge the gap or connect people together in terms of common technique and common language about what software will do. There are some key components that we must got to know of-
- Who, What, Why
- Acceptance Criteria
- Supporting Models
USE CASE captures the goals to be achieved by using a System. In General, there is a formal template for USE CASE Specification document. As below-
[Title] Use Case
|Document Title||Title of use case|
- Brief Description
We must aware of that ‘This USE CASE starts When…’ and ‘This USE CASE ends When….’
A person or system fulfilling a role will be the actor in one of the steps.
List anything that must be true before this process or functionality begins. Preconditions should be states that a system can validate to be true.
- Basic Flow
The basic flow is the normal course of events. Create a numbered list of each step.
- Alternate/Exception Flows
An Alternate flow is a variation from the basic flow. Alternatives can be triggered at any step in the basic flow and often reinsert the actors back into the basic flow.
An Exception flow is an error, or a negative condition. When an exception is encountered, it prevents the process from finishing through to its conclusion until it’s addressed.
- Post Conditions
Post-conditions indicate what must be true of the state of the system after the steps of the use case are complete.
- Visual Model
Many use cases are enhanced by a visual model. A simple work-flow diagram can be used to visually show the sequence of steps and alternate and exception flows.
USE CASE Example:-
“A Patient calls the Clinic to make an appointment for yearly checkup. The Receptionist finds the nearest empty time slot in the appointment book and schedules the appointment for the time slot”.
- Brief Description
This Use Case describes how an appointment process is schedules as per time slot when a patient calls to Clinic Receptionist.
Clinic Management System
Doctors Availability Time
Lab Facility should be provided
- Basic Flow of Events
This Use Case begins when a Patient Calls the Clinic Receptionist
Use Case: Validate Patient is to be Registered with Hospital.
Clinic Prompts for an ID generation
Patient selects a Department (as per his requirement)
Clinic prompts for a Registration Payment
The Patient pays the Registration Amount
Then Required Department and Doctor should be allocated when the Registration Fees paid
Patient visits the Clinic and go for a Test As per Doctors prescription
Reception generates a Discharge Ticket for a patient after clearing full dues.
Patient is Restricted to Access the System
- Alternative Flows
Invalid Patient: If a Patient is not Registered with Clinic, then Validation is a failure.
Non-Availability of Doctors and related Departments
- Key Scenarios
No Response from Clinic
Successful Completion: The Clinic received full payments from Patients and at the same time Internal System have been Updated accordingly
Failure Condition: The System have been Updated accordingly
- Special Requirements
Clinic payment mode will be done in the form of Cash or Card system
Clinic Transaction details will be inter-linked with Clinic Centralized Billing System (CBS)
USE CASE Benefits:-
- Use Cases are described using the language of the Customer
- Use Cases are provide a contractual delivery process
USE CASE Drawbacks:-
- Use Cases makes stating non-functional requirements difficult.