Specification for package drawing

About the explanation of package diagram
1. To clarify the relationship between packages
There are two kinds of relationship ：

And the dependence ：

use ： Use relationship , Is a default dependency , Description customer package （ The sender ） Elements in use provider packages in some way （ The arrow points to the package ） The common elements of , That is, the client package depends on the provider package .
import： Reference relationship , The most common package dependency type , Description provider package ( The arrow points to the package ) The namespace of （ The package itself represents a namespace ） Will be added to the customer package （ The sender ） In the namespace of , Elements in the client package also have access to all common elements of the provider package .
access： Visit relationship , Just want to use the elements in the provider package , Instead of merging their namespaces, you should use this relationship .
trace： Retroactive relationship , Want to express the historical development of one package to another , You need to use 《trace》 Relationship to express .

2. The elements in the package :
class 、 Interface 、 artifacts 、 node 、 Collaboration 、 Use cases 、 Other packages or drawings

3. Principles of drawing package diagram ：
Each package must have a unique package name
The elements in the package diagram must not exceed the six elements in the specification
Minimize the dependency between packages , Minimize... In each package public , protected Element number , Maximize in each package private Element number
The relationship between packages cannot have circular dependency
You can embed a sub package in the package
The package diagram shall reflect the hierarchical relationship between packages , A hierarchy of packages is placed on a diagram . In general , Just draw the package relationship at the first level

4. example ：