[Solved] In designing a Library Management System, which design pattern best handles the dynamic assignment of different user roles (e.g., Member, Librarian, Guest) with varying permissions? | OOP & Design Patterns

OOP & Design Patterns - Design a Library Management System - LLD with Relationships & Edge Cases

In designing a Library Management System, which design pattern best handles the dynamic assignment of different user roles (e.g., Member, Librarian, Guest) with varying permissions?

AStrategy pattern to encapsulate role-specific behaviors and switch them at runtime

BFactory pattern to create user objects based on role type

CObserver pattern to notify users of book availability changes

DSingleton pattern to ensure only one instance of each role exists

Step-by-Step Solution

Solution:

Step 1: Identify the need for dynamic behavior changes based on user roles
The system requires different behaviors for users depending on their roles, which can change or be assigned dynamically.
Step 2: Evaluate design patterns for behavior encapsulation and flexibility
The Strategy pattern allows encapsulating algorithms or behaviors and switching them at runtime, fitting the need for role-based permissions.
Step 3: Analyze other options and their limitations
Singleton ensures single instances but does not handle behavior changes; Observer is for event notification, not role behavior; Factory creates objects but does not manage behavior switching.
Final Answer:
Option A -> Option A
Quick Check:
Strategy pattern fits dynamic role behavior switching [OK]

Quick Trick: Dynamic behavior changes -> Strategy pattern [OK]

Common Mistakes:

MISTAKES

Confusing Factory with behavior management
Using Singleton for role instances
Choosing Observer for user role behavior

Trap Explanation:

PITFALL

Candidates often pick Factory or Singleton, misunderstanding that these patterns don't encapsulate behavior changes dynamically.

Interviewer Note:

CONTEXT

Tests understanding of behavioral design patterns in role-based access control.

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More OOP & Design Patterns Quizzes

In designing a Library Management System, which design pattern best handles the dynamic assignment of different user roles (e.g., Member, Librarian, Guest) with varying permissions?

Step 1: Identify the need for dynamic behavior changes based on user roles

Step 2: Evaluate design patterns for behavior encapsulation and flexibility

Step 3: Analyze other options and their limitations

Final Answer:

Quick Check:

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