Programmer Think

Structural patterns can describe two different things - classes and instances of classes (i.e. objects). 1. Adapter Pattern: convert the interface of a class into another interface desired by the customer. The Adapter Pattern allows those classes with incompatible interfaces to work together. The adapter contains the following three roles. ( ...

Author: Wang Chenyan When we are developing applications, we usually introduce SDKs, and most SDKs require us to initialize in the Application. When we introduce more and more SDKs, the Application will become longer and longer. If the initialization tasks of the SDK depend on each other, we have to deal with many condition judgments. At thi ...

What is singleton mode This pattern involves a single class that is responsible for creating its own objects while ensuring that only a single object is created. This class provides a way to access its unique object, which can be accessed directly without instantiating the object of this class. matters needing attention Singleton mode can on ...

introduce Singleton pattern is the most commonly used and simplest design pattern. The main use scenario is on various tool classes in program development. Its function is to ensure that there is only one instance of a class in the whole program. example We generally divide the single case mode into hungry man single case mode and lazy man m ...

Demand background Take a scenario. For example, at this time, we wrote a restaurant class to make different faces for users according to their needs. So how to achieve it at this time? The conventional writing method may be to take the user input as a variable, and then make if for this variable If there are n kinds of faces, there are ...

Author: Wang Chenyan preface When we are developing applications, we usually introduce SDKs, and most SDKs require us to initialize in the Application. When we introduce more and more SDKs, the Application will become longer and longer. If the initialization tasks of the SDK depend on each other, we have to deal with many condition judgment ...

We must put forward such tasks for ourselves: first, learning, second, learning, and third, learning. There is never a shortcut to learning. You can reach the peak step by step. 1, Introduction to single example design mode The so-called class singleton design pattern is to take certain methods to ensure that there can only be one obj ...

1, Builder mode 1. Basic introduction Builder moms, also known as generator pattern, is an object construction pattern. It can abstract the construction process of complex objects, so that different implementation methods of this abstract process can construct objects with different expressions.Builder mode is to create a complex object s ...

*** Advantages of builder mode: In the builder mode, the client does not need to know the internal composition details of the product, and separates the product itself from the product creation process, so that the same creation process can create different product objects;Different builders are independent of each other without any chain, ...

This note is obtained from station B crazy God speaking Java What is a design pattern The significance of learning design patterns GoF23 Seven principles of oop (1) Opening and closing principle: a software entity should be open to expansion and closed to modification; (2) Richter substitution principle: inheritance must ensure th ...