Mar 30th, 2023
The Chain of Responsibility Pattern is a behavioral design pattern that allows us to decouple the sender of a request from its receiver by creating a chain of receiver objects. Each receiver object in the chain has the ability to handle the request, and if it cannot handle the request, it passes the request on to the next receiver in the chain.
The Chain of Responsibility Pattern is useful when we have a set of objects that can handle a request, but we don't know which object will handle the request at runtime. The pattern allows us to create a dynamic chain of objects that can handle the request in a flexible and extensible way.
Let's take an example of an employee leave management system. The system has multiple levels of approval for employee leave requests, such as manager approval, HR approval, and executive approval. The approval process is based on the employee's seniority level and the duration of the leave request.
To implement the approval process using the Chain of Responsibility Pattern, we can create a chain of approval objects that can handle the leave request. Each approval object has a reference to the next approval object in the chain, and if it cannot handle the request, it passes the request on to the next approval object.
The first approval object in the chain is the manager, followed by the HR, and then the executive. When a leave request is submitted, the manager object is responsible for handling the request. If the manager approves the request, the process ends, and if not, the request is passed on to the HR object. If the HR approves the request, the process ends, and if not, the request is passed on to the executive object. If the executive approves the request, the process ends, and if not, the request is rejected.
By using the Chain of Responsibility Pattern, we can implement a flexible and extensible approval process that can handle different types of leave requests and can be easily modified in the future. We can also decouple the sender of the request from its receiver and reduce the coupling between the objects in the system.
In conclusion, the Chain of Responsibility Pattern is a powerful behavioral design pattern that allows us to create a chain of receiver objects that can handle a request in a flexible and extensible way. By using the pattern, we can decouple the sender of the request from its receiver and reduce the coupling between the objects in the system.