Factory method pattern

refactoring Factory Method

Problem

NOTE:

logistics management application 后勤管理系统

truck 卡车

原文所举的例子容易理解

As a result, you will end up with pretty nasty code, riddled（充斥） with conditionals that switch the app’s behavior depending on the class of transportation objects.

NOTE: 在Theory\Design-pattern\OOP-design-pattern\Summary-of-design-pattern.md中，已经总结了“Design pattern让我们避免使用if-else分支”。

Solution

Subclasses can alter the class of objects being returned by the factory method.

There’s a slight limitation though: subclasses may return different types of products only if these products have a common base class or interface. Also, the factory method in the base class should have its return type declared as this interface.

All products must follow the same interface.

Structure

Pseudocode

Applicability

维基百科Factory method pattern