A team with a unified mind is easy to lead instead! – Gu Ling

The introduction

  • Best Practices: Design patterns have evolved over a long period of time to summarize best practices.
  • Unified thinking: Design patterns provide a standard terminology system that is specific to a particular situation.

Seven principles of design patterns

  • Single responsibility principle: a class is responsible for one responsibility.
  • Open and close principle: extensible, not modifiable.
  • Richter’s substitution rule: define the base class, run the subclass.
  • Dependency inversion principle: Details depend on abstraction, interface oriented programming, dependencies generated through interfaces or abstract classes.
  • Demeter’s rule: Least know the rule and only communicate with immediate friends.
  • Interface isolation principle: The dependency of one class on another class should be based on the smallest interface.
  • Principle of composite reuse: composition/aggregation is better than inheritance.

Classification of design patterns

  • Creation pattern: Creation of key objects.

· Singleton, factory method, Abstract factory, Builder, prototype.

  • Structural patterns: Focus on a combination of objects.

· Adapter, decoration, agent, appearance, bridge, combination, share element.

  • Behavioral pattern: Focuses on the communication of objects.

· Policy, template method, observer, iterator, chain of responsibility, command, memo, status, visitor, mediator, interpreter.

Design pattern progression

Ladle package

(1) Singleton mode

(2) Factory mode (simple, factory, abstract)

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