1. Background

We all know that UML is really important for technical documentation. Whether it is to deepen your understanding or to show and communicate more friendly.
In the process of writing the DD document (SW Detailed Design) of ASPICE, it is often necessary to draw pictures, such as the description of the following content, the timing design of internal and external interfaces, this will need to use the Sequence diagram (sequence diagram) in UML to clarify The process of expressing the entire sequence diagram. Although there are many visual UML drawing tools like Visio and StartUML, it still takes a lot of time to drag and drop components, which is very inefficient.

Recently, I was chatting with Android colleagues about how they draw these UML diagrams. They introduced the following pretty good drawing tool—PlantUML. PlantUML is a component that can quickly write UML diagrams. You can use PlantUml to draw the process Figure, to achieve drawing like writing code. It is essentially a design language that can quickly draw pictures, and it is also very convenient to learn. PlantUML can draw almost all UML diagrams, but the ones I usually draw most with it are sequence diagrams and flowcharts. You can experience it on the website of open source tools for drawing UML diagrams . It supports the online version.
The best thing is that it has related plug-ins to download and use in VSCode and IDEA.

PlantUML official website link

2. How to install PlantUML

Search for the plug-in PlantUML in IDEA and download it. It can be used after restarting IDEA.
insert image description here

3. How to use PlantUML

Right click > New > PlantUML
insert image description here

4. Drawing type

Activity Diagram
https://plantuml.com/activity-diagram-beta
insert image description here

Class class diagram
https://plantuml.com/class-diagram
insert image description here

Component diagram
https://plantuml.com/component-diagram
insert image description here

Deployment deployment diagram
https://plantuml.com/deployment-diagram
insert image description here

Gantt Gantt Chart
https://plantuml.com/gantt-diagram
insert image description here

Mind Map mind map
https://plantuml.com/mindmap-diagram
insert image description here

Object object diagram
https://plantuml.com/zh/object-diagram
insert image description here
Sequence sequence diagram
https://plantuml.com/zh/sequence-diagram

State state diagram
https://plantuml.com/state-diagram

insert image description here

Use Case Diagram
https://plantuml.com/zh/use-case-diagram
insert image description here

Salt Wireframe
https://plantuml.com/zh/salt
insert image description here

WBS work breakdown structure
https://plantuml.com/zh/wbs-diagram
insert image description here
YAML display effect diagram
https://plantuml.com/zh/yaml

5. Drawing practice

Express this diagram in PlantUML
insert image description here

@startuml
autonumber

第三方调用者 -> 认证中心:  采用携带车机账号（vin码）、signature签名、nonce随机字符串、APIKey、APISecret请求鉴权服务
认证中心  <--  第三方调用者: 返回Access_token、车机账号（vin码）以及Token有效期（expire_time）
第三方调用者 -> 业务接口服务: 请求的Header中携带Access_token、车机账号（vin码）以及签名signature进行业务请求，涉及自定义的签名算法

认证中心 -> 业务接口服务: 校验签名signature有效性（更新token过期时间）
业务接口服务 <-- 认证中心: 校验成功
业务接口服务 -> 第三方调用者:返回业务结果

@enduml

insert image description here

6. Other good things recommended

【Recommendation】PuTTY, a free SSH and Telnet client

[Good things recommended] JSONView, an artifact for viewing json data

【Recommendation】LICEcap – flexible and easy to use, GIF screen recording tool

[Good things recommended] UML plug-in tool in IDEA-PlantUML