Chain of Responsibility pattern in LLD - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding the Chain of Responsibility Pattern

Which of the following best describes the main purpose of the Chain of Responsibility pattern?

A It allows multiple objects to handle a request without coupling the sender to the receiver by passing the request along a chain until an object handles it.

B It creates a single object responsible for handling all requests directly without delegation.

C It duplicates the request to all objects in a list so all handle it simultaneously.

D It forces the sender to know exactly which object will handle the request before sending it.

💡 Hint

Think about how requests are passed along in a chain until handled.

The Chain of Responsibility pattern passes a request along a chain of objects until one handles it, reducing coupling between sender and receiver.

❓ Architecture

intermediate

Identifying Components in Chain of Responsibility

In a Chain of Responsibility design, which component is responsible for deciding whether to handle a request or pass it to the next handler?

A The factory that creates handlers.

B The client that creates the request.

C The receiver object outside the chain.

D The handler object in the chain.

💡 Hint

Consider which object in the chain processes or forwards the request.

The handler object decides to process the request or pass it along the chain, making option D correct.

❓ scaling

advanced

Scaling Chain of Responsibility for High Throughput

You have a Chain of Responsibility handling requests in a web server. To scale for high throughput, which approach is best?

A Make the chain synchronous so each request waits for the previous to finish.

B Create multiple independent chains and distribute requests among them to process in parallel.

C Add more handlers to a single chain to increase processing power sequentially.

D Use a single handler to avoid overhead of passing requests along the chain.

💡 Hint

Think about parallel processing and avoiding bottlenecks.

Multiple independent chains allow parallel processing of requests, improving throughput, unlike a single sequential chain.

❓ tradeoff

advanced

Tradeoffs in Chain of Responsibility Pattern

What is a common tradeoff when using the Chain of Responsibility pattern in system design?

A It improves processing speed but tightly couples sender and receiver.

B It simplifies code but requires all handlers to process every request.

C It reduces coupling but can increase request processing time due to passing along the chain.

D It eliminates the need for handlers but increases client complexity.

💡 Hint

Consider the balance between flexibility and performance.

The pattern reduces coupling but may increase latency as requests pass through multiple handlers before being processed.

❓ estimation

expert

Estimating Maximum Chain Length for Performance

You design a Chain of Responsibility where each handler adds 2ms processing time. For a max acceptable latency of 100ms per request, what is the maximum number of handlers in the chain?

A 50 handlers

B 100 handlers

C 25 handlers

D 200 handlers

💡 Hint

Divide max latency by time per handler.

100ms max latency / 2ms per handler = 50 handlers max.