Decorator mode in Design Mode

Modifier mode: dynamically attaches the responsibility to the object. If you want to extend the function, the modifier provides another option that is different from inheritance.

Principles: (5) open to extensions and disable modifications

Key points: (1) inheritance is one of the extension forms, but it is not necessarily the best way to achieve elastic design.

(2) In our design, we should allow behavior extension without having to modify the existing code.

(3) combination and delegation can be used to dynamically add new behaviors during runtime

(4) Apart from inheritance, the modifier mode also allows us to expand our behavior.

(5) The decorator Mode means a group of decorator classes which are used to package specific components.

(6) The decorator class reflects the type of the component of the decorator.

(7) The decorator Can add his/her own behaviors before/or after the actions of the decorator, and even replace the actions of the decorator for a specific purpose.

(8) You can package a component with countless decorators.

(9) The decorator is generally transparent to the customer of the component, unless the customer program depends on the specific type of the component

(10) The decorator will lead to many small objects in the design. Excessive use will complicate the program.