活动图

动作(Action)
用(状态名)表示一个状态，其中(start)和(end)分别表示开始状态和结束状态，箭头->表示状态的转换

![](http://upload-images.jianshu.io/upload_images/46259-3e723bb2cdec264a?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)->(Boil Kettle)->(end))

->(Boil Kettle)->(end))

判断和限制(Decisions and Constraints)
使用<判断名>表示一个条件判断，其后跟[条件]->表示满足条件后状态的转换，用不同的判断名来标示不同的判断位置

![](http://upload-images.jianshu.io/upload_images/46259-3e723bb2cdec264a?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)-><a>[kettle empty]->(Fill kettle)->(Boil kettle),<a>[kettle full]->(Boil kettle)->(end))

-><a>[kettle empty]->(Fill kettle)->(Boil kettle),<a>[kettle full]->(Boil kettle)->(end))

分支合并(Fork/Join)
使用||表示分支或者合并点

![](http://upload-images.jianshu.io/upload_images/46259-3e723bb2cdec264a?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)-><a>[kettle empty]->(Fill kettle)->|b|,<a>[kettle full]->|b|->(Boil kettle)->|c|,|b|->(Add Tea Bag)->(Add Milk)->|c|->(Pour Water)->(end))

-><a>[kettle empty]->(Fill kettle)->|b|,<a>[kettle full]->|b|->(Boil kettle)->|c|,|b|->(Add Tea Bag)->(Add Milk)->|c|->(Pour Water)->(end))

对象(Objects)
符号[]表示一个对象

![](http://upload-images.jianshu.io/upload_images/46259-3e723bb2cdec264a?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)->[Water]->(Fill kettle)->(end))

->[Water]->(Fill kettle)->(end))

连接器名称(Connector Name)
在->中加入名称，-名称>表示命名连接器

![](http://upload-images.jianshu.io/upload_images/46259-3e723bb2cdec264a?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)-fill>(Fill kettle)->(end))

-fill>(Fill kettle)->(end))