Three detailed explanations of java factory pattern

There are three most common ones: simple factory pattern, factory method pattern and abstract factory pattern. Detailed explanation: 1. Simple factory pattern: The most basic factory pattern, which creates objects through a factory class. The client passes a simple parameter to the factory class, and the factory class decides which type of object to create based on this parameter. The simple factory pattern usually only includes one factory class and multiple product classes; 2. Factory method pattern: The factory method pattern defines an interface for creating objects, but delays the specific creation work to subclasses, etc.

Operating system for this tutorial: Windows 10 system, Dell G3 computer.

Factory pattern is a creational design pattern that provides the best way to create objects while hiding the details of creating objects. Factory pattern includes many forms, the most common of which are three: simple factory pattern, factory method pattern and abstract factory pattern. The following is a detailed explanation of these three factory patterns:

1. Simple Factory Pattern:

Simple Factory Pattern is the most basic factory pattern , which creates objects through a factory class. The client passes a simple parameter to the factory class, and the factory class decides which type of object to create based on this parameter. The simple factory pattern usually only includes one factory class and multiple product classes.

Advantages:

Hide the creation details of specific products from the client.

The client only needs to know the interfaces of the factory class and product class, reducing the degree of coupling.

Disadvantages:

When adding a new product class, the code of the factory class needs to be modified, which does not comply with the opening and closing principle.

2. Factory Method Pattern:

The Factory Method Pattern defines an interface for creating objects, but defers the specific creation work to subclasses middle. Each specific factory class is responsible for creating its own product. The factory method pattern includes abstract factory class, concrete factory class, abstract product class, and concrete product class.

Advantages:

Conforms to the opening and closing principle. When adding a new product category, there is no need to modify the existing code, just add new specific factories and product categories.

Reduces the coupling between the client and specific product categories.

Disadvantages:

It is necessary to create a specific factory class for each specific product class, and the number of classes will increase rapidly.

3. Abstract Factory Pattern:

The Abstract Factory Pattern provides an interface for creating a family of related or dependent objects without specifying Concrete class. The abstract factory pattern includes abstract factory class, concrete factory class, abstract product class and concrete product class.

Advantages:

The client uses abstract interfaces and does not need to care about specific factories and product classes.

Conforms to the opening and closing principle and can easily add new product families.

Disadvantages:

When adding new product categories, the abstract factory and all specific factory classes need to be modified, which is not flexible enough.

In actual applications, choosing which factory pattern to use depends on specific needs and design considerations. The simple factory pattern is suitable for situations where the factory class is responsible for creating fewer objects, while the factory method pattern and abstract factory pattern are suitable for situations where multiple related objects or product families need to be created.

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