[design mode] Adapter mode and appearance mode

The previous decorator pattern was to wrap objects and give them new functionality. The adapter pattern is to wrap objects so that their interfaces do not look like themselves but other objects, that is, to convert the interface of the class into the desired interface in order to implement different interfaces. The appearance mode, in turn, wraps the object to simplify its interface.

The adapter mode tells the interface of a class and transforms it into another interface that the customer expects. Adapters allow classes that are incompatible with the original interface to work together.

The appearance mode provides a unified interface for accessing a group of interfaces in a subsystem. The appearance defines a high-level interface that makes the subsystem easier to use. This model also shows a design principle, the least knowledge principle.

[design mode] Adapter mode and appearance mode