Chain of Responsibility pattern in LLD - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare the next handler reference in the Chain of Responsibility pattern.

LLD

class Handler {
    Handler [1];
}

Drag options to blanks, or click blank then click option'

AnextHandler

BhandleRequest

Cprocess

Drequest

Attempts:

3 left

💡 Hint

Common Mistakes

Using method names instead of variable names.

Naming the variable unrelated to the chain.

The next handler in the chain is typically stored in a variable named nextHandler.

2fill in blank

medium

Complete the code to forward the request to the next handler if current handler cannot process it.

LLD

void handleRequest(Request req) {
    if (canHandle(req)) {
        process(req);
    } else if ([1] != null) {
        [1].handleRequest(req);
    }
}

Drag options to blanks, or click blank then click option'

AnextHandler

Brequest

Chandler

Dprocess

Attempts:

3 left

💡 Hint

Common Mistakes

Using the request variable instead of the next handler.

Calling process instead of forwarding the request.

The request is passed to the nextHandler if the current handler cannot process it.

3fill in blank

hard

Fix the error in the code to correctly set the next handler in the chain.

LLD

void setNextHandler(Handler [1]) {
    this.nextHandler = next;
}

Drag options to blanks, or click blank then click option'

Ahandler

Bnext

CnextHandler

Drequest

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different parameter name than the one assigned.

Confusing the instance variable with the parameter.

The parameter name should match the variable used inside the method. Here, next is the parameter.

4fill in blank

hard

Fill both blanks to complete the method that processes the request or forwards it.

LLD

void handleRequest(Request req) {
    if ([1](req)) {
        [2](req);
    } else if (nextHandler != null) {
        nextHandler.handleRequest(req);
    }
}

Drag options to blanks, or click blank then click option'

AcanHandle

Bprocess

ChandleRequest

Dforward

Attempts:

3 left

💡 Hint

Common Mistakes

Calling handleRequest recursively instead of process.

Using incorrect method names.

The method canHandle checks if the handler can process the request, and process executes the handling.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps handler names to their status if they can handle a request.

LLD

status_map = {handler.[1]: handler.[2] for handler in handlers if handler.[3](request)}

Drag options to blanks, or click blank then click option'

Aname

Bstatus

CcanHandle

Dprocess

Attempts:

3 left

💡 Hint

Common Mistakes

Using process instead of canHandle in the condition.

Mixing up keys and values in the dictionary.

The comprehension maps each handler's name to its status if it canHandle the request.