Notification on state change in LLD - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a method that triggers notification on state change.

LLD

def notify_on_state_change(self, new_state):
    if new_state != self.current_state:
        self.current_state = new_state
        self.[1]()

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

Alog_change

Bupdate_state

Csend_notification

Dreset_state

Attempts:

3 left

💡 Hint

Common Mistakes

Calling a method that only updates state without notifying.

Using a logging method instead of notification.

The method send_notification is called to notify when the state changes.

2fill in blank

medium

Complete the code to register an observer for state changes.

LLD

def register_observer(self, observer):
    self.[1].append(observer)

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Aobservers

Bnotifications

Clisteners

Dsubscribers

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable that does not store observers.

Using a singular form instead of plural.

The list observers holds all registered observers to notify on state changes.

3fill in blank

hard

Fix the error in notifying all observers about the state change.

LLD

def notify_all(self):
    for observer in self.[1]:
        observer.update(self.current_state)

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

Asubscribers

Bobservers

Cnotifications

Dlisteners

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong variable name causing runtime errors.

Using a variable that does not hold observer objects.

The method iterates over observers to call their update method with the new state.

4fill in blank

hard

Fill both blanks to create a dictionary mapping states to notification messages.

LLD

state_messages = {
    'active': '[1]',
    'inactive': '[2]'
}

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

A'User is now active'

B'User is now inactive'

C'State changed to active'

D'State changed to inactive'

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping messages between states.

Using generic messages that do not specify state.

The dictionary maps each state to a clear notification message.

5fill in blank

hard

Fill all three blanks to implement a method that sends notifications with proper message and logs the event.

LLD

def send_notification(self, message):
    self.notification_service.[1](message)
    self.logger.[2](f"Notification sent: [3]")

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

Asend

Binfo

Cmessage

Dalert

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect method names causing errors.

Logging wrong variable or missing message content.

The notification service send method sends the message, and the logger info method logs the message content.