Use-case analysis

Use case analysis is a technique used to identify the requirements of a system (normally associated with software/process design) and the information used to both define processes used and classes (which are a collection of actors and processes) which will be used both in the use case diagram and the overall use case in the development or redesign of a software system or program. The use case analysis is the foundation upon which the system will be built.

A use case analysis is the primary form for gathering usage requirements for a new software program or task to be completed. The primary goals of a use case analysis are: designing a system from the user’s perspective, communicating system behavior in the user’s terms, and specifying all externally visible behaviors. Another set of goals for a use case analysis is to clearly communicate: system requirements, how the system is to be used, the roles the user plays in the system, what the system does in response to the user stimulus, what the user receives from the system, and what value the customer or user will receive from the system.

This walkthrough will set out one example of how to go about a use case analysis. There are many variations of how to develop a use case analysis, and finding the right method can take time.

A Use-case realization describes how a particular use case is realized within the design model, in terms of collaborating objects.

The Realization step sets up the framework within which an emerging system is analysed. This is where the first, most general, outline of what is required by the system is documented. This entails rough breakdown of the processes, actors, and data required for the system. These are what comprise the classes of the analysis.

Once the general outline is completed, the next step is to describe the behavior of the system visible to the potential user of the system. While internal behaviors can be described as well, this is more related to designing a system rather than gathering requirements for it. The benefit of briefly describing internal behaviors would be to clarify with potential users that the system is not missing a vital component externally due to it being completed internally. The overall goal of this step is to provide just enough detail to understand what classes are required for the system. Too much detail can make it difficult to change the system later on.

This step narrows down the class list into those classes that are capable of performing the behavior needed to make the system function successfully. If no classes yet exist for a system, they must be created before this step can be completed. Classes can be created in many ways from many sources. A few examples are: previous—but similar—systems, enterprise models, and data mining. Once classes are created and narrowed down, relationships must be developed between classes, now called analysis classes, which model the task of the system.

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