Vocabulary Flashcards
Actors
Classes that define roles that objects external to a system may play
Use Case
Classes that define a sequence of interactions (units of functionality) between the actor and the system.
Class
A set of objects with the same characteristics or a common implementation.
Object
Well-defined representational constructs of concrete or conceptual entities that provide an understanding of the real world
Attribute
A data value, or structural characteristic, held by an object in a cass
Operation
The specification of a function performed by an object; a behavioral characteristic of an object
Use Case modeling
An approach for describing the functional requirements of a system
Software Requirements
Describe the functionality that the system must provide for the users.
Requirements Specification
The document that needs to be agreed on by the requirements analysis and the users.
Functional requirement
Describes the functionality a system must be capable of providing in order to fulfill the purpose of the system
Nonfunctional requirement
a.k.a Quality Attribute: refers to a quality of service goal that the system must fufill
Three examples of nonfunctional requirements:
performance requirement, availability requirement, security requirement
Quality Attributes of Software Requirements Specification (SRS)
- Correct
- Complete
- Unambiguous
- Consistent
- Verifiable
- Understandable by a non-computer specialist
- Modifiable
- Traceable
Use Case Model
Describes the functional requirements of the system in terms of actors and use cases. The system is a black box. It only matters what the system does not how the system does it.
Actors that are not human include:
external systems, I/O devices, timers
Primary Actor
The actor that initiates the use case, usually the actor that gains value from the use case
Secondary Actor
An actor other than the primary actor that participates in the use case.
Five Types of Actors
- Human
- External System Actor
- Input Device Actor
- Input/Output Device Actor (typically a sensor)
- Timer Actor
Senario
Each complete sequence through the use case
Main Sequence
The most common sequence of interactions between the actor and the system
Use Case Description Sections
Use Case Name Summary Dependency Actors Preconditions Description of the Main Sequence Description of alternative Sequences Nonfunctional requirements Postcondition Outstanding Questions
Alternative Sequence
Other situations that occur less frequently
Inclusion Use Case
Functionality that is common to more than one use case, usually cannot be executed on its own. The inclusion use case is reusable.
The include relationship
The relationship between the base use case and the inclusion use case. The included use case is pointed to from the base use case by a dotted line and denoted as a relationship with the > notation.
The extend Relationship
Used to model alternative paths that a use case may take; used to show a conditional part of the vase use case that is executed only under certain circumstances; used to model complex or alternative paths.
Extension points
Used to specify the precise location in a base case where extensions can be added. (is given a name) contains a condition to select the extension use case. Only one condition can be true (Mutually exclusive)
Use Case Package
Group of related use cases that represent high-level requirements that address major subsets of the functionality of the system
Activity Diagram
Diagram that depicts the flow of control and sequence of activities, decision nodes, loops and concurrent activities; ;represents the sequential steps of a use case
