Registry Pattern

Introduction

The Registry Pattern is a design pattern that provides a centralized repository of objects, allowing for easy access and management. It is particularly useful in scenarios where multiple components need to interact with each other in a decoupled manner.

Definition

The Registry Pattern defines a registry class that holds references to various objects or services, allowing clients to look up and retrieve instances as needed.

Key Concepts

• Centralized Management: All components use the registry to access shared resources.
• Decoupling: Components do not need to be aware of each other's existence.
• Singleton Instances: The registry can maintain singleton instances of objects for consistent access.

Implementation

Below is a simple implementation of the Registry Pattern in Python:

class Registry:
    _instances = {}

    @classmethod
    def register(cls, name, instance):
        cls._instances[name] = instance

    @classmethod
    def get(cls, name):
        return cls._instances.get(name)

# Example usage
class Database:
    pass

db = Database()
Registry.register('db', db)

retrieved_db = Registry.get('db')
print(retrieved_db is db)  # Output: True
                

Best Practices

• Limit the number of objects stored in the registry to avoid memory overhead.
• Use meaningful names for registered objects to ensure clarity.
• Implement lazy loading if object creation is resource-intensive.

Registry Pattern Flowchart

graph TD;
                A[Start] --> B[Client Requests Object];
                B --> C{Is Object Registered?};
                C -->|Yes| D[Retrieve Object];
                C -->|No| E[Create New Object];
                D --> F[Return Object];
                E --> G[Register Object];
                G --> F;
                F --> H[End];