Structural patterns (Adapter, Decorator, Facade) in Software Engineering - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding the Adapter Pattern

Which of the following best describes the main purpose of the Adapter pattern?

A It adds new responsibilities to an object dynamically without changing its interface.

B It creates objects without specifying the exact class of object to create.

C It allows incompatible interfaces to work together by converting one interface into another.

D It provides a simplified interface to a complex subsystem.

💡 Hint

Think about how two different plugs can fit into the same socket using a converter.

The Adapter pattern acts like a bridge between two incompatible interfaces, allowing them to work together without changing their existing code.

🧠 Conceptual

intermediate

Role of the Decorator Pattern

What is the primary benefit of using the Decorator pattern in software design?

A It converts one interface into another to enable compatibility.

B It allows behavior to be added to individual objects dynamically without affecting others.

C It simplifies a complex system by hiding its details behind a single interface.

D It ensures only one instance of a class exists throughout the application.

💡 Hint

Consider how you might add toppings to a pizza one by one without changing the pizza itself.

The Decorator pattern lets you add new features to objects at runtime, keeping the original object unchanged and allowing flexible extensions.

🚀 Application

advanced

Identifying the Facade Pattern Use Case

You have a complex library with many classes and methods. You want to provide a simple interface for common tasks so users don't get overwhelmed. Which pattern should you apply?

A Facade

B Decorator

C Adapter

D Singleton

💡 Hint

Think about how a TV remote simplifies controlling many devices.

The Facade pattern offers a simple interface to a complex subsystem, making it easier for users to interact with it without understanding all details.

🔍 Analysis

advanced

Comparing Adapter and Decorator Patterns

Which statement correctly distinguishes the Adapter pattern from the Decorator pattern?

A Both Adapter and Decorator simplify complex systems by hiding details behind a single interface.

B Decorator ensures only one instance exists, Adapter creates new objects dynamically.

C Adapter adds new behavior dynamically, while Decorator converts one interface to another.

D Adapter changes an object's interface to match another, while Decorator adds new behavior without changing the interface.

💡 Hint

Focus on whether the pattern changes the interface or adds behavior.

Adapter changes the interface so two incompatible interfaces can work together. Decorator adds new behavior to an object without changing its interface.

❓ Reasoning

expert

Choosing the Right Structural Pattern

A software system has multiple complex subsystems. You want to provide a simple interface for clients, allow adding new features to objects dynamically, and enable incompatible interfaces to work together. Which combination of patterns best achieves these goals?

A Facade for simple interface, Decorator for adding features, Adapter for interface compatibility

B Adapter for simple interface, Facade for adding features, Decorator for interface compatibility

C Decorator for simple interface, Adapter for adding features, Facade for interface compatibility

D Singleton for simple interface, Adapter for adding features, Facade for interface compatibility

💡 Hint

Match each pattern to its main strength: Facade simplifies, Decorator extends, Adapter connects.

The Facade pattern simplifies complex subsystems with a simple interface. The Decorator pattern adds new features dynamically. The Adapter pattern enables incompatible interfaces to work together.