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This article introduces the relevant knowledge of "what is the applicable scenario of Prototype mode". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

The applicable scenario of the Prototype pattern is when a system should be independent of its product creation, composition, and presentation, and

Forget the "and" and just look at the first half of the sentence. In other words, the part that builds the product is separated from other functions of the system. If you only look at this point, the abstract factory pattern is also suitable. Fortunately, there is a "and" that combines this with the following three conditions (actually one of the three) to form the application scenario of the prototype pattern.

When the class to be instantiated is specified at run time, for example, by dynamically loading

To put it simply, dynamic loading is the generation of products from data (saved in a file when possible, or from communication data) when the program is executed. The opposite is static loading: the product is generated by hard coding. At this point, the object type is determined in the coding phase. For example, when an abstract factory generates an object, although the creation action is performed when the program is running, information such as the type of the generated object is determined in the coding phase.

Or to avoid creating a factory class hierarchy parallel to the product class hierarchy

When building a product using an abstract factory or factory method, you need a Factory or Creator class parallel to the product category. The prototype pattern produces new objects by cloning existing objects, which can be used as an option to avoid this disadvantage.

Or when an instance of a class can only have one of several different combinations of states. It may be more convenient to build a corresponding number of prototypes and clone them than to instantiate the class manually with the appropriate state each time.

If we can generate instances that meet the requirements simply by combining objects, we can use the prototype pattern to build new instances by cloning existing objects instead of building new classes.

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