56 Resource: Munawar, 2005
2.11.1 Use Case Diagram
Usecase diagram is a description of a system from a user perspective. Use cases work by describing a typical interactionbetween the user of a system with its
own system through a story of how a system is used. Sequence of steps that describe theuser with a system called a scenario. Each scenario describes the
sequence of events. Each sequence is initialized by the people, the other system, hardware or time
sequence. Three components in
theuse case diagram are
actors, associations and use-case line. Actors are the abstraction of people and system that actives the function of
the target system. Person or system can appear in multiple roles. Actors interact with the use case but have no control over the use case. Actors usually can be user
who interacts with software or information system. But actors can be other computer system that interacts with the software Interaction is indicated by a
straight line
from one
component to
another component.
While the ellipse represents a use case that isan abstraction of the interaction between the
system with the actor.Use case is based on the purposes of the actor. Use cases should be the what is done the software application, not the how
ofsoftware applications to do it. Each use case should be given aname that says what it achieved
from the interaction with theactors. Name
of use case may consist of several words and there should be no use case has the same
name.
57 Stereotype is a special model is limited to certain conditions. To realize the
stereotypes used the symbol diawalnya and closed under the symbol an end. extend Used to show that one use case is a functional addition of
another use case if certain conditions or requirements are met. While include used to describe the use case that was entirely the functionality of another use
case. Usually include is used to prevent copying of a use case because it is often used.
Each use case should be described in a document called the document flow of event. This document defines what should be done by the system when the
actors to enable the use case. The structure of the document use case can very, but generally this description should at least contain Munawar , 2005;
- Brief Description - Actor who involved
- Precondition the importance thing for the use case to start - Detail description of the flow event that include:
o Main flow of the event specified can be divided into:
- Sub Flow o
Alternative Flow - Post condition which describes the state of the system after the use case ends.
2.11.2 Class Diagram
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