One of the nine diagrams of UML’s are the Use-case Diagram. These are not only important but necessary requirement for software projects. It is basically used in Software life cycles. As we know there are various phases in the development cycle and the most used phase for Use-cases would be during the requirements gathering phase.

What is a Use-Case?

A use-case describes a sequence of actions, performed by a system that provides value to an actor. The use-case describes the system’s behavior under various conditions as it responds to a request from one of the stakeholders, called the primary actor.

The actor is the Who of the system, in other words he the end user.

In software and systems engineering, a use-case is a list of steps, typically defining interactions between a role (known in UML as an “actor”) and a system, to achieve a goal. The actor can be a human or an external system.

A use-case specifies the flow of events in the system. It is more concerned with what is performed by the system in order to perform the sequence of actions.

Benefits of a Use-Case

A use-case provides the following benefits −

●      It is an easy means of capturing the functional requirement with a focus on value added to the user.

●      Use-cases are relatively easy to write and read compared to the traditional requirement methods.

●      Use-cases force developers to think from the end user perspective.

●      Use-case engage the user in the requirement process.

The Anatomy of a Use-Case

Name : Descriptive name that illustrates the purpose of the use-case.

Description : Describes what the use-case does in couple of sentences.

Actor : List any actors that participate in the use-case.

Pre-condition : Conditions that must be met prior to starting the use-case.

Flow of events : Description of interaction between the system and the actor.

Post Condition : Describe the state of the system after a use-case has run its course.