CSC/ECE 517 Fall 2010/ch4 4a I: Difference between revisions
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=Introduction= | ==Introduction== | ||
A '''use case''' is set of interactions between the external '''actors''' and the '''system''' under consideration with an objective of achieving specific goals as defined by the users of the system. A use case is used to capture the functional requirements of a particular system which in turn are used to capture the intended behavior of the system. The notion of an '''actor''' can be used to represent the external users, or the roles of the users, in fact even the systems other than the one under consideration are considered to be and '''actor'''.[http://www.bredemeyer.com/use_cases.htm 2] | A '''use case''' is set of interactions between the external '''actors''' and the '''system''' under consideration with an objective of achieving specific goals as defined by the users of the system. A use case is used to capture the functional requirements of a particular system which in turn are used to capture the intended behavior of the system. The notion of an '''actor''' can be used to represent the external users, or the roles of the users, in fact even the systems other than the one under consideration are considered to be and '''actor'''.[http://www.bredemeyer.com/use_cases.htm 2] | ||
=Overview= | ==Overview== | ||
In general '''use cases''' are used to capture the '''who''' i.e the actors, the '''what''' i.e interactions, and the '''purpose''' i.e the goal of a particular system without having to worry too much about the internal workings of the system. | In general '''use cases''' are used to capture the '''who''' i.e the actors, the '''what''' i.e interactions, and the '''purpose''' i.e the goal of a particular system without having to worry too much about the internal workings of the system. Use cases originated in the Object oriented community but their applicability is not limited to object oriented systems. | ||
=References= | ==Use cases in detail== | ||
===Purpose of Use cases=== | |||
Use cases are used in different stages on the development life cycle. In the '''planning''' stage, the process of defining important use cases helps to clarify the most important goals of the system. Use cases helps to narrow the scope of the project. They can surface often unspoken assumptions about the desired behavior of the system. | |||
In the '''execution''' stage of the development life cycle, use cases provide developers key parts of the specification. Some systems are built entirely with only use case descriptions from sponsors | |||
===Use case components=== | |||
====Role==== | |||
Before defining the actors interaction with the system, the role played by these actors should be defined. A '''role''' is an instance of an encapsulated set of properties and behavior. Roles are defined independent of the object(s) that may implement it. | |||
====Actors==== | |||
Use cases identify the intent satisfying the role assumed by external '''actors''' interacting with the “system under discussion/test”. The actors can be classified into '''primary actor''' or '''secondary actor'''. A '''primary actor''' is one having a goal requiring the assistance of the system. A '''secondary actor''' is one from which the system needs assistance to satisfy a goal. | |||
==References== | |||
*[1]: [http://en.wikipedia.org/wiki/Use_case Use case] | *[1]: [http://en.wikipedia.org/wiki/Use_case Use case] | ||
*[2]: [http://www.bredemeyer.com/use_cases.htm Functional Requirements and Use cases] | *[2]: [http://www.bredemeyer.com/use_cases.htm Functional Requirements and Use cases] | ||
Revision as of 15:43, 20 October 2010
Introduction
A use case is set of interactions between the external actors and the system under consideration with an objective of achieving specific goals as defined by the users of the system. A use case is used to capture the functional requirements of a particular system which in turn are used to capture the intended behavior of the system. The notion of an actor can be used to represent the external users, or the roles of the users, in fact even the systems other than the one under consideration are considered to be and actor.2
Overview
In general use cases are used to capture the who i.e the actors, the what i.e interactions, and the purpose i.e the goal of a particular system without having to worry too much about the internal workings of the system. Use cases originated in the Object oriented community but their applicability is not limited to object oriented systems.
Use cases in detail
Purpose of Use cases
Use cases are used in different stages on the development life cycle. In the planning stage, the process of defining important use cases helps to clarify the most important goals of the system. Use cases helps to narrow the scope of the project. They can surface often unspoken assumptions about the desired behavior of the system. In the execution stage of the development life cycle, use cases provide developers key parts of the specification. Some systems are built entirely with only use case descriptions from sponsors
Use case components
Role
Before defining the actors interaction with the system, the role played by these actors should be defined. A role is an instance of an encapsulated set of properties and behavior. Roles are defined independent of the object(s) that may implement it.
Actors
Use cases identify the intent satisfying the role assumed by external actors interacting with the “system under discussion/test”. The actors can be classified into primary actor or secondary actor. A primary actor is one having a goal requiring the assistance of the system. A secondary actor is one from which the system needs assistance to satisfy a goal.
References
- [1]: Use case