状态图
状态图(Statechart Diagram)是描述一个实体基于事件反应的动态行为，显示了该实体如何根据当前所处的状态对不同的事件做出反应。
mermaid关键字stateDiagram或stateDiagram-v2
方向
语法direction TB/BT/RL/LR，默认TB
状态定义
| 简单状态 | stateDiagram-v2 direction LR s1 --> s2 | |
| 别名 | stateDiagram-v2 direction LR state "this is state s1" as s1 s2: this is state s2 s1 --> s2: 连接描述 | |
| 开始和结束 | stateDiagram-v2 direction LR %% [*]在左边表示开始右边表示结束 [*] --> [*] | |
| 复合状态 |
stateDiagram-v2
[*] --> First
state First {
[*] --> Second
state Second {
[*] --> second
second --> Third
state Third {
[*] --> third
third --> [*]
}
}
}
| |
| 选择 |
stateDiagram-v2
%% 关键语法
state if_state <<choice>>
[*] --> IsPositive
IsPositive --> if_state
if_state --> False: if n < 0
if_state --> True : if n >= 0
False --> [*]
True --> [*]
| |
| fork/join状态 |
stateDiagram-v2
state fork_state <<fork>>
%% fork语法
[*] --> fork_state
fork_state --> State2
fork_state --> State3
%% join语法
state join_state <<join>>
State2 --> join_state
State3 --> join_state
join_state --> State4
State4 --> [*]
| |
| 并发状态 |
stateDiagram-v2
[*] --> Active
state Active {
[*] --> NumLockOff
NumLockOff -->
NumLockOn : EvNumLockPressed
NumLockOn -->
NumLockOff : EvNumLockPressed
--
[*] --> CapsLockOff
CapsLockOff -->
CapsLockOn : EvCapsLockPressed
CapsLockOn -->
CapsLockOff : EvCapsLockPressed
}
| |
| 备注 |
stateDiagram-v2
State1: The state with a note
%% 多行备注
note right of State1
Important information!
You can write break line
notes.
end note
State1 --> State2
%% 单行备注
note left of State2 : note left
| |
综合示例
以java线程状态为例
stateDiagram-v2
[*] --> Runnable: start()
Runnable --> Running: cpu schedule
Running --> Runnable: cpu schedule
bwp: Blocked in object's wait pool
blp: Blocked in object's lock pool
Running --> bwp: wait() must have lock
bwp --> blp: notify()/interrupt()
blp --> Runnable: acquires lock
Running --> blp: synchronized
Running --> Block: block event
Block --> Runnable: block event end
Running --> [*]: run() complete
| |