PlantUML シーケンス図（２）ｉｆ文

if文 then のみ

@startuml
participant 処理A as a
participant 処理B as b
participant 処理C as c

|||
activate a
	a -> b
	activate b
		b --> a
	deactivate b
	opt value > 0
		a -> c
		activate c
			c --> a
		deactivate c
	end
|||

@enduml

if～else文

@startuml
participant 処理A as a
participant 処理B as b
participant 処理C as c

|||
activate a
	alt value > 0
		a -> b
		activate b
			b --> a
		deactivate b
	else
		a -> c
		activate c
			c --> a
		deactivate c
	end
|||

@enduml

if～複数else文

@startuml
participant 処理A as a
participant 処理B as b
participant 処理C as c

|||
activate a
	alt value > 0
		a -> b
		activate b
			b --> a
		deactivate b
	else value == 0
		a -> c
		activate c
			c --> a
		deactivate c
	else value < 0
		a -> a
	end
|||

@enduml

note を付ける
note right または note left ～ end note

@startuml
participant 処理A as a
participant 処理B as b
participant 処理C as c

|||
activate a
	alt value > 0
		a -> b
		activate b
			b --> a
		deactivate b
	else value == 0
		a -> c
		activate c
			c --> a
		deactivate c
	else value < 0
		a -> a
		note right 
			負の時の処理説明
		end note 		
	end
|||

@enduml

グループラベル

@startuml
participant 処理A as a
participant 処理B as b
participant 処理C as c

|||
activate a
	alt value > 0
		a -> b
		activate b
			b --> a
		deactivate b
	else value == 0
		group グループ
			a -> c
			activate c
				c --> a
			deactivate c
		end
	else value < 0
		a -> a
	end
|||

@enduml

色を付ける

@startuml
participant 処理A as a
participant 処理B as b
participant 処理C as c

|||
activate a
	alt#yellow #gold value > 0
		a -> b
		activate b
			b --> a
		deactivate b
	else value == 0
		group#pink #papayawhip グループ
			a -> c
			activate c
				c --> a
			deactivate c
		end
	else #lightblue value < 0
		a -> a
	end
|||

@enduml