The pattern “Prototype” refers to the group of creational patterns.
Suppose we are developing applications for dating Tender, according to the business model, we have a paid opportunity to make copies of our own profile by changing the name automatically, and the order of photos in places. This is done in order for the user to be able to conduct several profiles at once with a different set of friends in the application.
By clicking on the button to create a copy of the profile, we need to implement a profile copy, auto name generation and re-sort the photos.
Pseudocode:
fun didPressOnCopyProfileButton() {
let profileCopy = new Profile()
profileCopy.name = generateRandomName()
profileCopy.age = profile.age
profileCopy.photos = profile.photos.randomize()
storage.save(profileCopy)
}
Now imagine that other team members made a copy-paste copy code or invented it from scratch, and after that a new field was added – likes. This field stores the number of profile likes, now you need to update * all * of the place where copying takes place manually, adding a new field. It is very long and difficult to maintain the code, as in testing.
To solve this problem, a prototype design pattern was invented. Let’s create a common copying protocol, with the copy () method which returns a copy of the object with the required fields. After changing the entity fields, you will need to update only one copy() method, instead of manually searching and updating all places containing the copy code.
References
https://refactoring.guru/design-patterns/prototype