The Chain of Responsibility pattern fits any scenario where a request needs to pass through a series of potential handlers until one of them is able to process it, without the sender needing to know which handler will ultimately succeed.
Key Points: • Handlers are tried in sequence, and each decides independently whether to process the request or pass it on. • The client only needs a reference to the first handler in the chain, not the full list. • New handlers can be inserted into the chain without changing the client code that initiates requests. • It's well suited to escalation-style workflows where responsibility increases along the chain. • It also fits filter or middleware-style pipelines, like request validation or HTTP request processing.
Example: In a customer support system, a request might first reach a front-line representative, then escalate to a technical support agent, then to a manager, with each level attempting to resolve the issue before passing it further up the chain.
Interview Tip: A concise interview answer is:
"A good example is a support escalation flow — a request passes from a front-line rep to a technical agent to a manager, with each handler resolving it or passing it on, so the customer's initial request doesn't need to know in advance who will actually handle it."