{"id":6681,"date":"2022-05-31T01:57:13","date_gmt":"2022-05-31T01:57:13","guid":{"rendered":"https:\/\/www.booksofall.com\/vi\/?post_type=product&p=6681"},"modified":"2022-06-15T03:28:15","modified_gmt":"2022-06-15T03:28:15","slug":"scenarios-and-use-cases","status":"publish","type":"product","link":"https:\/\/www.booksofall.com\/vi\/scenarios-and-use-cases\/","title":{"rendered":"Scenarios and Use Cases"},"content":{"rendered":"

In\u00a0software<\/a>\u00a0and\u00a0systems engineering<\/a>, the phrase\u00a0use case<\/b>\u00a0is a\u00a0polyseme<\/a>\u00a0with two\u00a0senses<\/a>:<\/p>\n

    \n
  1. A usage scenario for a piece of software; often used in the plural to suggest situations where a piece of software may be useful.<\/li>\n
  2. A potential scenario in which a system receives an external request (such as user input) and responds to it.<\/li>\n<\/ol>\n

    This article discusses the latter sense.<\/p>\n

    A\u00a0use case<\/i>\u00a0is a list of actions or event steps typically defining the interactions between a role (known in the\u00a0Unified Modeling Language<\/a>\u00a0(UML) as an\u00a0actor<\/a><\/i>) and a system to achieve a goal. The actor can be a human or other external system. In systems engineering, use cases are used at a higher level than within\u00a0software engineering<\/a>, often representing missions or\u00a0stakeholder<\/a>\u00a0goals. The detailed requirements may then be captured in the\u00a0Systems Modeling Language<\/a>\u00a0(SysML) or as contractual statements.<\/p>\n

    General principle<\/span><\/h3>\n

    Use cases are a technique for capturing, modelling and specifying the requirements of a system. A use case corresponds to a set of behaviours that the system may perform in interaction with its actors, and which produces an observable result that contribute to its goals. Actors represent the role that human users or other systems have in the interaction.<\/p>\n

    In the\u00a0requirement analysis<\/a>, at their identification, a use case is named according to the specific user-goal that it represents for its primary actor. The case is further detailed with a textual description or with additional graphical models that explains the general sequence of activities and events, as well as variants such as special conditions, exceptions or error situations.<\/p>\n

    According to the\u00a0Software Engineering Body of Knowledge (SWEBOK)<\/a>, use cases belong to the scenario-based\u00a0requirement elicitation<\/a>\u00a0techniques, as well as the\u00a0model-based analysis<\/a>\u00a0techniques. But the use cases also supports narrative-based requirement gathering, incremental requirement acquisition, system documentation, and acceptance testing.<\/p>\n

    Variations<\/span><\/h3>\n

    There are different kinds of use cases and variations in the technique:<\/p>\n