== 유즈 케이스 다이어그램


Let's have few examples :

Note that you can disable the shadowing using the `+skinparam shadowing false+` command.


== 유즈케이스
유즈케이스는 (두개의 괄호는 원으로 보이기 때문에) 괄호로 싸서 표현합니다.

아니면 `+usecase+` 키워를 이용하여 정의할 수 있습니다.
그리고 `+as+` 키워드를 이용하여 별칭을 정의 할 수 있습니다.
별칭은 관계를 정의할 때 사용됩니다.
<plantuml>
@startuml

(First usecase)
(Another usecase) as (UC2)
usecase UC3
usecase (Last\nusecase) as UC4

@enduml
</plantuml>



== Actors

The name defining an actor is enclosed between colons.

You can also use the `+actor+` keyword to define an actor.
An alias can be assigned using the `+as+` keyword and can be used later instead of the actor's name, e. g. when defining relations.

You can see from the following examples, that the actor definitions are optional.
<plantuml>
@startuml

:First Actor:
:Another\nactor: as Man2
actor Woman3
actor :Last actor: as Person1

@enduml
</plantuml>


== Change Actor style

You can change the actor style from stick man __(by default)__ to:
* an awesome man with the `+skinparam actorStyle awesome+` command;
* a hollow man with the `+skinparam actorStyle hollow +` command.

=== Stick man __(by default)__
<plantuml>
@startuml
:User: --> (Use)
"Main Admin" as Admin
"Use the application" as (Use)
Admin --> (Admin the application)
@enduml
</plantuml>

=== Awesome man 
<plantuml>
@startuml
skinparam actorStyle awesome
:User: --> (Use)
"Main Admin" as Admin
"Use the application" as (Use)
Admin --> (Admin the application)
@enduml
</plantuml>

__[Ref. https://forum.plantuml.net/10493/how-can-i-customize-the-actor-icon-in-svg-output?show=10513#c10513[QA-10493]]__

=== Hollow man 
<plantuml>
@startuml
skinparam actorStyle Hollow 
:User: --> (Use)
"Main Admin" as Admin
"Use the application" as (Use)
Admin --> (Admin the application)
@enduml
</plantuml>

__[Ref. https://github.com/plantuml/plantuml/pull/396[PR#396]]__


== 유즈케이스 종류


If you want to have description on several lines, you can use quotes.

You can also use the following separators: `+--+`
`+..+` `+==+` `+__+`.
And you can put titles within the separators.

<plantuml>
@startuml

usecase UC1 as "You can use
several lines to define your usecase.
You can also use separators.
--
Several separators are possible.
==
And you can add titles:
..Conclusion..
This allows large description."

@enduml
</plantuml>



== Use package

You can use packages to group actors or use cases.

<plantuml>
@startuml
left to right direction
actor Guest as g
package Professional {
  actor Chef as c
  actor "Food Critic" as fc
}
package Restaurant {
  usecase "Eat Food" as UC1
  usecase "Pay for Food" as UC2
  usecase "Drink" as UC3
  usecase "Review" as UC4
}
fc --> UC4
g --> UC1
g --> UC2
g --> UC3
@enduml
</plantuml>


You can use `+rectangle+` to change the display of the package.

<plantuml>
@startuml
left to right direction
actor "Food Critic" as fc
rectangle Restaurant {
  usecase "Eat Food" as UC1
  usecase "Pay for Food" as UC2
  usecase "Drink" as UC3
}
fc --> UC1
fc --> UC2
fc --> UC3
@enduml
</plantuml>


== 기본 예제


To link actors and use cases, the arrow `+-->+` is
used.

The more dashes `+-+` in the arrow, the longer the
arrow.
You can add a label on the arrow, by adding a `+:+`
character in the arrow definition.

In this example, you see that __User__ has not been defined
before, and is used as an actor.
<plantuml>
@startuml

User -> (Start)
User --> (Use the application) : A small label

:Main Admin: ---> (Use the application) : This is\nyet another\nlabel

@enduml
</plantuml>




== Extension

If one actor/use case extends another one, you can use the symbol `+<|--+`.

<plantuml>
@startuml
:Main Admin: as Admin
(Use the application) as (Use)

User <|-- Admin
(Start) <|-- (Use)

@enduml
</plantuml>



== Using notes

You can use the `+note left of+` , `+note right of+` ,
`+note top of+` , `+note bottom of+` keywords to
define notes related to a single object.

A note can be also define alone with the `+note+`
keywords, then linked to other objects using the `+..+` symbol.

<plantuml>
@startuml
:Main Admin: as Admin
(Use the application) as (Use)

User -> (Start)
User --> (Use)

Admin ---> (Use)

note right of Admin : This is an example.

note right of (Use)
  A note can also
  be on several lines
end note

note "This note is connected\nto several objects." as N2
(Start) .. N2
N2 .. (Use)
@enduml
</plantuml>



== Stereotypes

You can add stereotypes while defining actors and use cases using `+<<+`
and `+>>+`.

<plantuml>
@startuml
User << Human >>
:Main Database: as MySql << Application >>
(Start) << One Shot >>
(Use the application) as (Use) << Main >>

User -> (Start)
User --> (Use)

MySql --> (Use)

@enduml
</plantuml>



== 화살표 방향 변경

기본적으로, 클래스간의 링크는 대쉬2개 `+--+` 로 표시하고 수직방향이다.
다음 처럼 대쉬1개 (혹은 점)을 넣어서 수평방향 링크를 사용할 수 있다:

<plantuml>
@startuml
:user: --> (Use case 1)
:user: -> (Use case 2)
@enduml
</plantuml>

You can also change directions by reversing the link:

<plantuml>
@startuml
(Use case 1) <.. :user:
(Use case 2) <- :user:
@enduml
</plantuml>

It is also possible to change arrow direction by adding `+left+`, `+right+`, `+up+`
or `+down+` keywords inside the arrow:

<plantuml>
@startuml
:user: -left-> (dummyLeft)
:user: -right-> (dummyRight)
:user: -up-> (dummyUp)
:user: -down-> (dummyDown)
@enduml
</plantuml>

You can shorten the arrow by using only the first character of the direction (for example, `+-d-+` instead of
`+-down-+`)
or the two first characters (`+-do-+`).

Please note that you should not abuse this functionality : __Graphviz__ gives usually good results without
tweaking.



== Splitting diagrams

The `+newpage+` keywords to split your diagram into several pages or images.
<plantuml>
@startuml
:actor1: --> (Usecase1)
newpage
:actor2: --> (Usecase2)
@enduml
</plantuml>



== Left to right direction

The general default behavior when building diagram is **top to bottom**.
<plantuml>
@startuml
'default
top to bottom direction
user1 --> (Usecase 1)
user2 --> (Usecase 2)

@enduml
</plantuml>
You may change to **left to right** using the `+left to right direction+` command.
The result is often better with this direction.

<plantuml>
@startuml

left to right direction
user1 --> (Usecase 1)
user2 --> (Usecase 2)

@enduml
</plantuml>



== Skinparam


You can use the link::skinparam[skinparam]
command to change colors and fonts for the drawing.

You can use this command :
* In the diagram definition, like any other commands,
* In an link::preprocessing[included file],
* In a configuration file, provided in the link::command-line[command line] or the link::ant-task[ANT task].

You can define specific color and fonts for stereotyped actors and usecases.

<plantuml>
@startuml
skinparam handwritten true

skinparam usecase {
BackgroundColor DarkSeaGreen
BorderColor DarkSlateGray

BackgroundColor<< Main >> YellowGreen
BorderColor<< Main >> YellowGreen

ArrowColor Olive
ActorBorderColor black
ActorFontName Courier

ActorBackgroundColor<< Human >> Gold
}

User << Human >>
:Main Database: as MySql << Application >>
(Start) << One Shot >>
(Use the application) as (Use) << Main >>

User -> (Start)
User --> (Use)

MySql --> (Use)

@enduml
</plantuml>



== Complete example


<plantuml>
@startuml
left to right direction
skinparam packageStyle rectangle
actor customer
actor clerk
rectangle checkout {
  customer -- (checkout)
  (checkout) .> (payment) : include
  (help) .> (checkout) : extends
  (checkout) -- clerk
}
@enduml
</plantuml>


== Business Use Case

You can add  `+/+` to make Business Use Case.

=== Business Usecase
<plantuml>
@startuml

(First usecase)/
(Another usecase)/ as (UC2)
usecase/ UC3
usecase/ (Last\nusecase) as UC4

@enduml
</plantuml>

=== Business Actor
<plantuml>
@startuml

:First Actor:/
:Another\nactor:/ as Man2
actor/ Woman3
actor/ :Last actor: as Person1

@enduml
</plantuml>


__[Ref. https://forum.plantuml.net/12179/[QA-12179]]__