活动标签(activity label)以冒号开始,以分号结束。
文本格式支持creole wiki语法。
活动默认安装它们定义的顺序就行连接。
@startuml :Hello world; :This is on defined on several **lines**; @enduml

开始/结束
你可以使用关键字start和stop表示图示的开始和结束。
@startuml start :Hello world; :This is on defined on several **lines**; stop @enduml

也可以使用 end 关键字。
@startuml start :Hello world; :This is on defined on several **lines**; end @enduml

条件语句
在图示中可以使用关键字if,then和else设置分支测试。标注文字则放在括号中。
@startuml start if (Graphviz installed?) then (yes) :process all diagrams; else (no) :process only __sequence__ and __activity__ diagrams; endif stop @enduml

也可以使用关键字elseif设置多个分支测试。
@startuml start if (condition A) then (yes) :Text 1; elseif (condition B) then (yes) :Text 2; stop elseif (condition C) then (yes) :Text 3; elseif (condition D) then (yes) :Text 4; else (nothing) :Text else; endif stop @enduml

重复循环
你可以使用关键字repeat和repeatwhile进行重复循环。
@startuml start repeat :read data; :generate diagrams; repeat while (more data?) stop @enduml

while循环
可以使用关键字while和end while进行while循环。
@startuml start while (data available?) :read data; :generate diagrams; endwhile stop @enduml

还可以在关键字endwhile后添加标注,还有一种方式是使用关键字is。
@startuml while (check filesize ?) is (not empty) :read file; endwhile (empty) :close file; @enduml

并行处理
你可以使用关键字fork,fork again和end fork表示并行处理。
@startuml
start
if (multiprocessor?) then (yes)
fork
:Treatment 1;
fork again
:Treatment 2;
end fork
else (monoproc)
:Treatment 1;
:Treatment 2;
endif
@enduml

注释
文本格式支持creole wiki语法。
A note can be floating, using floating keyword.
@startuml start :foo1; floating note left: This is a note :foo2; note right This note is on several //lines// and can contain <b>HTML</b> ==== * Calling the method ""foo()"" is prohibited end note stop @enduml

标题和图例
你可以给图表(diagram)添加标题、标头、脚注和图例。
@startuml
title this is my title
if (condition?) then (yes)
:yes;
else (no)
:no;
note right
this is a note
end note
endif
stop
legend
this is the legend
endlegend
footer dummy footer
header
this is
a long __dummy__ header
end header
@enduml

颜色
你可以为活动(activity)指定一种颜色。
@startuml start :starting progress; #HotPink:reading configuration files These files should edited at this point!; #AAAAAA:ending of the process; @enduml

箭头
使用->标记,你可以给箭头添加文字或者修改箭头颜色。
It's also possible to have dotted, dashed, bold or hidden arrows.
@startuml :foo1; -> You can put text on arrows; if (test) then -[#blue]-> :foo2; -[#green,dashed]-> The text can also be on several lines and **very** long...; :foo3; else -[#black,dotted]-> :foo4; endif -[#gray,bold]-> :foo5; @enduml

组合(grouping)
通过定义分区(partition),你可以把多个活动组合(group)在一起。
@startuml
start
partition Initialization {
:read config file;
:init internal variable;
}
partition Running {
:wait for user interaction;
:print information;
}
stop
@enduml

泳道(Swimlanes)
你可以使用管道符|来定义泳道。
还可以改变泳道的颜色。
@startuml |Swimlane1| start :foo1; |#AntiqueWhite|Swimlane2| :foo2; :foo3; |Swimlane1| :foo4; |Swimlane2| :foo5; stop @enduml

分离(detach)
可以使用关键字detach移除箭头。
@startuml :start; fork :foo1; :foo2; fork again :foo3; detach endfork if (foo4) then :foo5; detach endif :foo6; detach :foo7; stop @enduml

特殊领域语言(SDL)
通过修改活动标签最后的分号分隔符(;),可以为活动设置不同的形状。
|<>/]}
@startuml :Ready; :next(o)| :Receiving; split :nak(i)< :ack(o)> split again :ack(i)< :next(o) on several line| :i := i + 1] :ack(o)> split again :err(i)< :nak(o)> split again :foo/ split again :i > 5} stop end split :finish; @enduml

一个完整的例子
@startuml
start
:ClickServlet.handleRequest();
:new page;
if (Page.onSecurityCheck) then (true)
:Page.onInit();
if (isForward?) then (no)
:Process controls;
if (continue processing?) then (no)
stop
endif
if (isPost?) then (yes)
:Page.onPost();
else (no)
:Page.onGet();
endif
:Page.onRender();
endif
else (false)
endif
if (do redirect?) then (yes)
:redirect process;
else
if (do forward?) then (yes)
:Forward request;
else (no)
:Render page template;
endif
endif
stop
@enduml
