Fixing Multiple If-Else problem with Chain of Responsibility Pattern

Situation will become unmanageable if we have lot of if else condition in our code, Lets understand problem and then we will see it’s Solution.

Problem with Multiple If Conditions
Using multiple if-else conditions to handle different cases can lead to code that is hard to read, maintain, and extend. Here’s a simple example using multiple if conditions in a leave management system.

We will implement below Business Logic for Leave management system

a. IF Leave < = 3, then Team Lead will approve

b. IF Leave < =5, then Project Manager will approve

c. IF Leave > 5, then HR Manager will approve

Request first go to team lead to check if Request can be handled by Team lead else it will go to Project Manager else request will go to HR manager

Example with Multiple If Conditions

public class LeaveRequest
{
    public string EmployeeName { get; set; }
    public int NumberOfDays { get; set; }
    public string Reason { get; set; }
}

public class LeaveApprovalService
{
    public void ApproveLeave(LeaveRequest request)
    {
        if (request.NumberOfDays <= 3)
        {
            Console.WriteLine($"Leave request by {request.EmployeeName} for {request.NumberOfDays} days approved by Team Lead.");
        }
        else if (request.NumberOfDays <= 5)
        {
            Console.WriteLine($"Leave request by {request.EmployeeName} for {request.NumberOfDays} days approved by Project Manager.");
        }
        else if (request.NumberOfDays > 5)
        {
            Console.WriteLine($"Leave request by {request.EmployeeName} for {request.NumberOfDays} days approved by HR Manager.");
        }
        else
        {
            Console.WriteLine("Leave request could not be processed.");
        }
    }
}

Problems in above code

Maintainability: The method becomes harder to maintain as the logic grows.

Single Responsibility Principle (SRP): The method does too much by handling all approval levels, violating the single responsibility principle.

*Testing * : Each time we add new condition we need to test end to end to make sure nothing is breaking because we are making changes into existing class because we are breaking SRP.

Solution with Chain of Responsibility Pattern

Please click here for fixing this problem