A post-condition of a use case lists possible states that the system can be in after the use case runs. The system must be in one of those states. A post-condition also states actions that the system performs at the end of the use case, regardless of what occurred in the use case.

A use case is a written description of how users will perform tasks on your website. It outlines, from a user’s point of view, a system’s behavior as it responds to a request. Each use case is represented as a sequence of simple steps, beginning with a user’s goal and ending when that goal is fulfilled.

For example a system use case might be “return book when overdue” and would describe the interactions of the various actors (borrower, librarian) with the system in carrying out the end-to-end process.

A rule of thumb is that a subflow should be a segment of behavior within the use case that has a clear purpose, and is “atomic” in the sense that you do either all or none of the actions described. The condition that needs to be fulfilled for the alternative behavior to start.

<> relationships: Include relationship is used to include one use case within the behavior sequence of another use case. The include use case never stand alone. When an actor initiates any base use case then base use case executes included use case.

A use case description is a text-based narrative of a functionality comprised of detailed, step-by-step interaction between the actor and the system. It describes the outcomes of an action taken to accomplish a specific goal. Also, some formats for use case descriptions include two columns.

A use case represents the actions that are required to enable or abandon a goal. A use case has multiple “paths” that can be taken by any user at any one time. A use case scenario is a single path through the use case. This article provides an example use case and some diagrams to help visualize the concept.

An association between an actor and a use case indicates that the actor and the use case somehow interact or communicate with each other. Only binary associations are allowed between actors and use cases. An actor could be associated to one or several use cases.

Use-case diagrams describe the high-level functions and scope of a system. These diagrams also identify the interactions between the system and its actors. The use cases and actors in use-case diagrams describe what the system does and how the actors use it, but not how the system operates internally.

A Use Case Specification is a textual description of the functionality provided by the system. It captures actor-system interaction. That is, it specifies how a user interacts with a system and how the system responds to the user actions. It is often phrased in the form of a dialog between the actor and the system.

Aligning the use case postconditions and preconditions is a usage-centric approach. Specifying the functional requirements informs the developer of functionality that he or she must implement to make sure the system is ready to proceed with use case 2.

A precondition is the state of the system and its surroundings that is required before the use case can be started. A postcondition is the states the system can be in after the use case has ended. Consider the following: The states described by pre- or postconditions should be states that the user can observe.

The precondition statement indicates whatmust be true before the function is called. The postcondition statement indicates whatwill be true when the function finishes itswork.

One way to specify such requirements iswith a pair of statements about the function. The precondition statement indicates whatmust be true before the function is called. The postcondition statement indicates whatwill be true when the function finishes itswork.