A role
Factory mode of action: allow users to separate the creator, in order to achieve the purpose of decoupling. Popular terms is not new object, but use the factory to create.
Two simple factory
1. The most common, simple, powerful
2. does not comply with the principle of opening and closing
Source
Defined interfaces
Define the implementation class
Factory class definitions, forgotten to put a static
The definition of the caller
These are simple plants, because the factory class to add static, also known as static factory methods.
Third, the factory method
To overcome the problem of simple extension of the factory: If you want to increase the implementation class, such as to add Mercedes to re-modify the code does not comply with the principle of opening and closing, so the design of the factory method pattern
1. difference
The new factory interface, so you can plant it can solve the above problems by a new class
New factory interface
Realization of class factory
The caller should be changed accordingly
By the above changes, then you want to add something, you can achieve class and the actual implementation class can be completed by the new plant.