[Solved] In the following code snippet, what is the main issue that breaks the Memento pattern?class Originator: def __init__(self): self._state = "" def set_state(self, state): self.... | LLD

LLD - Behavioral Design Patterns — Part 2

In the following code snippet, what is the main issue that breaks the Memento pattern?

class Originator:
    def __init__(self):
        self._state = ""
    def set_state(self, state):
        self._state = state
    def save(self):
        return self._state  # returns state directly
    def restore(self, memento):
        self._state = memento

originator = Originator()
originator.set_state("State1")
memento = originator.save()
originator.set_state("State2")
originator.restore(memento)
print(originator._state)

AThe save method returns state directly, exposing internal details

BThe restore method does not update the state

CThe Originator class lacks a Memento class

DThe set_state method is missing

Step-by-Step Solution

Solution:

Step 1: Analyze the save method
The save method returns the internal state directly instead of encapsulating it in a Memento object, exposing internal details.
Step 2: Understand Memento pattern principle
The pattern requires hiding the internal state inside a Memento object to prevent external access. Returning raw state breaks encapsulation.
Final Answer:
The save method returns state directly, exposing internal details -> Option A
Quick Check:
Save must hide state in Memento [OK]

Quick Trick: Save must return Memento, not raw state [OK]

Common Mistakes:

MISTAKES

Thinking restore method is faulty
Believing Memento class is mandatory in code
Ignoring encapsulation principle

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More LLD Quizzes

In the following code snippet, what is the main issue that breaks the Memento pattern?

Step 1: Analyze the save method

Step 2: Understand Memento pattern principle

Final Answer:

Quick Check:

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