Streamlining Leave Requests: The Chain of Responsibility Pattern

Introduction

Imagine the chaos in an office if every employee request landed directly on the CEO's desk! To ensure efficient handling of tasks like leave approvals, the chain of responsibility pattern offers a structured approach. Let's delve into how it works.

The Challenge: Juggling Approvals

In a typical leave approval process, requests flow through different levels based on the leave duration:

• Team Lead can approve short leaves (up to 2 days).
• Department Manager handles medium leaves (up to 5 days).
• HR takes care of extended leaves (beyond 5 days).

Traditionally, you might code these approvals directly within each manager class. This leads to issues like:

• Conditional Spaghetti: Code becomes cluttered with checks for different leave durations.
• Tight Coupling: Changes to the approval hierarchy require modifying existing classes.

The Chain's Solution: Delegation with Clarity

The chain of responsibility pattern introduces a series of handler objects that can pass a request along a chain until one of them handles it. Here's the breakdown:

1. IRequestHandler Interface: Define this interface with a HandleRequest method that takes the leave request as input. This establishes a common protocol for handlers. 
2. Concrete Handler Classes: Create classes like TeamLead, DepartmentManager, and HRDepartment that implement IRequestHandler. Each handler implements the HandleRequest method to check if it can approve the leave based on its authority.
3. Chained Handling (Optional): Each handler can hold a reference to the next handler in the chain. If the current handler cannot handle the request, it forwards it to the next one using this reference.

Example Code:

Benefits of the Chain of Responsibility Pattern

1. Loose Coupling: Objects don't need to know the specific handlers in the chain, promoting flexibility.
2. Extensible: Adding new approval levels is straightforward by creating a new handler class.
3. Organized Workflow: Clear separation between request handling and approval logic.
   

Conclusion

The chain of responsibility pattern facilitates a structured and flexible approach to handling requests. By creating a chain of handlers, you can streamline workflows and ensure efficient task delegation, just like a well-oiled leave approval process in your office!