Common design objects

 

I. appearance. No matter how complicated the internal details are, it only provides the interface required by the "consumer. All classes are appearance classes, and appearance classes are relatively speaking.

II. Specific implementation class of the appearance class. Some implementations provide interfaces that go beyond the appearance class, but basic interfaces are still used in the system.

3. Create a factory. This type is the easiest to modify. Is the specific implementation class required to create a system. The creation factory knows the usage details of specific implementation classes and is responsible for configuration. The creation class is used by the main process.