基本语法

每个普通节点：冒号开头，分号结尾

活动图的起始和结尾：start、end或stop

start

:case1;

:case2;

end

条件语句

start

if(predicate?) then (yes)

:case yes;

else (no)

:case no;

endif

end

多重条件语句

plaintUML里没有switch语法，只能使用elseif代替

start

note right:多分支条件语句，实现switch

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

do while循环

start

note right:do while循环

repeat

:read data;

:generate diagrams;

repeat while (more data?) is (yes)

stop

while后面可以跟is表达式来标识箭头

while do循环

start

note right:while do循环

while (check filesize ?) is (not empty)

:read file;

endwhile (empty)

:close file;

end

while后面可以跟is表达式来标识箭头

endwhile后跟括号表达式来标识箭头

并行处理

start

note right:并行处理fork

if (multiprocessor?) then (yes)

fork

:Treatment 1;

fork again

:Treatment 2;

end fork

else (monoproc)

:Treatment 1;

:Treatment 2;

endif

end

fork换成split，可以更改样式

注释

start

note right:添加注释

:foo1;

floating note left: This is a note

:foo2;

note right

This note is on several

//lines// and can

contain HTML

====

* Calling the method ""foo()"" is prohibited

end note

stop

一行注释可在note声明后跟冒号

多行注释需要换行，并用end note语句标识结束

浮动注释可使用floating关键字

note声明后可标识方位：仅支持left和right

文本格式支持creole wiki语法

节点颜色

start

note right:配置节点颜色

:starting progress;

#HotPink:reading configuration files

These files should edited at this point!;

#AAAAAA:ending of the process;

end

#开头，可使用色值或文字描述，需要放在语句前方

箭头颜色样式

start

note right:修改箭头颜色样式

: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;

end

连接器

start

note right:连接器

:Some activity;

(A)

detach

(A)

:Other activity;

end

组合

start

note right:组合:定义分区

partition Initialization {

:read config file;

:init internal variable;

}

partition Running {

:wait for user interaction;

:print information;

}

stop

分离

start

note right:分离

fork

:foo1;

:foo2;

fork again

:foo3;

detach

endfork

if (foo4) then

:foo5;

detach

endif

:foo6;

detach

:foo7;

stop

特殊领域语言

用其他符号代替分号结尾，可修改节点样式

|

<

>

/

]

}

start

note right:特殊领域语言(SDL)

: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;

end

泳道

泳道比较特殊，整个代码必须以泳道标识开头

类似于节点颜色，在语句前方可以设置颜色；后设置的颜色会覆盖之前设置的

|Swimlane1|

start

:foo1;

|#AntiqueWhite|Swimlane2|

:foo2;

:foo3;

|Swimlane1|

:foo4;

|Swimlane2|

:foo5;

stop