Prototype pattern
The Prototype pattern is a creational design pattern. This pattern is used to copy an existing object.
Example:
Think, there are products to sell. There is a “Product” interface, and several products will implement it.
So, we need to create product objects when we print product items on the bill. For creating a product object (Book) “Bill” class must be known all the products. We should edit the “Bill” class when adding a new product. It will violate the open-close principle. It means Classes should close for modification but open for extension. Another problem is the “Bill” class must know about all the products. (Tight coupling).
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Therefore, this implanting way should differ as follows.
First, we must separate the cloning method to the Product interface from the “Bill” class. Each product should have a clone method because each class must encapsulate cloning techniques for each item. Also, there must be a clone method in the Product interface because all products can be cloned. Now, the “Product” interface behaves as a prototype for all the products.
The “clone” method gives the new object.
The “Bill” class does not want to know what is the cloned object.
