Prototype Pattern Lesson

1. Introduction

The Prototype Pattern is a creational design pattern that allows you to create new objects by copying an existing object, known as the prototype. This pattern is particularly useful when the cost of creating a new object is more expensive than copying an existing one.

2. Definition

The Prototype Pattern defines a mechanism for creating new objects based on a template of an existing object through cloning. It provides a way to instantiate objects without specifying the exact class of the object to be created.

3. Key Concepts

• Cloning: The main functionality of the Prototype Pattern is to provide a way to clone existing objects.
• Prototype Interface: This is an interface that declares a method for cloning itself.
• Concrete Prototypes: Specific implementations of the Prototype interface that can be cloned.

4. Implementation

Here's a simple example of the Prototype Pattern in Python:

import copy

class Prototype:
    def clone(self):
        return copy.deepcopy(self)

class ConcretePrototype(Prototype):
    def __init__(self, name):
        self.name = name

# Usage
prototype = ConcretePrototype("Original")
clone = prototype.clone()
clone.name = "Clone"

print(prototype.name)  # Output: Original
print(clone.name)      # Output: Clone

5. Best Practices

When using the Prototype Pattern, consider the following best practices:

• Ensure that the objects being cloned are well-defined and maintain a clear contract.
• Use the Prototype Pattern when the cost of creating a new instance is greater than copying an existing instance.
• Make sure to implement the clone method in a way that avoids shared references to mutable objects.

6. FAQ