Category: Unified Modeling Language

A UML use case diagram is the primary form of system/software requirements for a new software program under developed. Use cases specify the expected behavior (what) of a system, and not the exact method of making it happen (how). A complete set of use cases specifies all the different ways to use the system and therefore defines all behavior required of the system bounding the scope of the system.

A use case is a written description of how a user performs a task on your system. It outlines the behavior of the system from the user’s perspective when responding to a request. Each use case is represented as a sequence of simple steps, starting with the user’s goal and ending when the goal is achieved.

Use Case 2.0 is a scalable and agile approach that uses use cases to capturing requirements and driving the incremental development of a system to fulfill them. It helps you understand how the system will be used and leading you through the development of an appropriate system to support the users.

A use case diagram models different types of users interact with the system to solve a problem. As such, it describes the goals of the users, the interactions between the users and the system, and the required behavior of the system in satisfying these goals. Use cases define interactions between external actors and the system to attain particular goals. A use case diagram contains four main components

Use case diagrams and activity diagrams are behavioral UML diagrams that describe the dynamic characteristics of a system. The difference between use case diagrams and activity diagrams is that use case diagrams help to model the system, user interactions, while activity diagrams help to model the workflow of the system and are often used to illustrate the internal logic of use cases. These diagrams offer multiple advantages. They help model business requirements and understand the functionality of the system at a high level.

UML can be used as much or as little as you like. Martin Fowler describes three common ways that people tend to use UML: (1) UML as a sketch ; (2) UML as a blueprint ; (3) UML as a programming language.

A state machine diagram is a behavior which specifies the sequence of states an object visits during its lifetime in response to events, together with its responses to those events.

Use cases describe how users use the system to achieve specific goals. A use-case diagram consists of a system, related use cases, and actors, and relates them to each other to visualize: What is it describing? (System), who is using the system? What are the actors trying to achieve? Thus, use cases help ensure that the right system is developed by capturing requirements from the user’s point of view.

Visual Paradigm Online (VP Online) Free Edition is a free online drawing tool that supports UML, ERD, Organization Chart, etc. It features a simple, intuitive yet powerful UML editor, which allows you to create professional UML diagrams smoothly and quickly. The free UML tool comes with no ad, no limited period of access and no limitations such as, number of diagrams, number of shapes and etc. You own the diagrams you created for personal and non-commercial purposes.