Professional Courses
Industry-relevant training in Business, Technology, and Design to help professionals and graduates upskill for real-world careers.
Categories
Interactive Games
Fun, engaging games to boost memory, math fluency, typing speed, and English skills—perfect for learners of all ages.
Typing
Memory
Math
English Adventures
Knowledge
Enroll to start learning
You’ve not yet enrolled in this course. Please enroll for free to listen to audio lessons, classroom podcasts and take practice test.
Interactive Audio Lesson
Listen to a student-teacher conversation explaining the topic in a relatable way.
Introduction to Design Patterns
Unlock Audio Lesson
Today, we will discuss Object-Oriented Design Patterns. Can anyone tell me what they think a design pattern is?
Isn't it like a template for solving problems in software design?
Exactly! Design patterns provide tried-and-true solutions to common problems developers face. There are three main categories we will focus on: creational, structural, and behavioral patterns. Let’s start with creational patterns. Who can guess what ‘creational’ means?
It probably has to do with how objects are created?
Correct! Creational patterns handle object creation mechanisms. They simplify the instantiation process. One such pattern is the Singleton pattern, which ensures a class only has one instance. To remember this, think of the word 'Single' in Singleton! What other creational patterns can you think of?
There's the Factory pattern, right?
And the Builder pattern!
Great! Remember, the Factory pattern allows subclasses to alter the types of objects created, while the Builder pattern separates the construction process from representation.
Structural Patterns
Unlock Audio Lesson
Now, let’s transition to structural patterns. What do you think structural patterns focus on?
They probably deal with how classes and objects are composed?
Exactly! They define the relationships between objects. An example is the Adapter pattern, which helps incompatible interfaces work together. Can you think of a situation where you might need an Adapter?
If I had a phone charger and it didn't fit my phone, I might use an adapter!
That's a perfect real-world analogy! Another structural pattern is the Composite, which allows clients to treat individual objects and compositions of objects uniformly. Can anyone summarize the Proxy pattern for us?
I think it acts like a placeholder or a surrogate?
Exactly right! Proxies are useful for controlling access to complicated objects.
Behavioral Patterns
Unlock Audio Lesson
Lastly, let's delve into behavioral patterns, which deal with how objects interact and communicate. What’s an example of a behavioral pattern?
The Observer pattern! It allows observers to be notified when a subject changes.
Fantastic! The Observer pattern promotes loose coupling and is perfect for event handling systems. Let’s also discuss the Strategy pattern. What does this pattern facilitate?
It lets you define a family of algorithms and switch between them!
Precisely! You can encapsulate algorithms so that they can be interchangeable. Lastly, does anyone remember what the Command pattern does?
It encapsulates a request as an object, allowing for parameterization.
Correct! Command patterns create flexibility in command execution.
Summary and Review
Unlock Audio Lesson
Let’s summarize the key points from our discussions on design patterns. Who can list the three main categories we covered?
Creational, structural, and behavioral patterns!
Correct! And what is the primary focus of creational patterns?
They handle object creation?
Exactly! And how about the structural patterns?
They focus on the composition of classes and objects!
Well done! Finally, what’s the purpose of behavioral patterns?
They define communication between objects?
Yes! Design patterns are crucial for creating reusable, maintainable, and scalable code in software development.
Introduction & Overview
Read a summary of the section's main ideas. Choose from Basic, Medium, or Detailed.
Quick Overview
Standard
Object-Oriented Design Patterns are established solutions to common problems in software design, divided into three main categories: creational patterns for object creation, structural patterns for organizing classes and objects, and behavioral patterns for managing communication between objects.
Detailed
Object-Oriented Design Patterns
Object-Oriented Programming (OOP) empowers developers to use reusable design patterns that provide standardized solutions to specific design issues. This section identifies three main categories of design patterns:
- Creational Patterns: These patterns focus on object creation mechanisms, attempting to create objects in a manner suitable to the situation. Examples include:
- Singleton: Ensures that a class has only one instance and provides a global point of access to it.
- Factory: Defines an interface for creating an object but lets subclasses alter the type of objects that will be created.
- Builder: Separates the construction of a complex object from its representation so that the same construction process can create different representations.
- Structural Patterns: Structural patterns deal with object composition, creating relationships between objects to form larger structures. Examples include:
- Adapter: Allows incompatible interfaces to work together by acting as a bridge.
- Composite: Lets clients treat individual objects and compositions of objects uniformly.
- Proxy: Provides a surrogate or placeholder to control access to an object.
- Behavioral Patterns: These patterns focus on communication between objects, defining how objects interact and the responsibilities of each object. Examples include:
- Observer: Allows a subject to notify observers when it changes, promoting loose coupling.
- Strategy: Lets you define a family of algorithms, encapsulate each one, and make them interchangeable.
- Command: Encapsulates a request as an object, thereby allowing for parameterization of clients with queues, requests, and operations.
Understanding and implementing these design patterns greatly enhances code reusability, modularity, and maintainability, aligning with the core principles of OOP discussed throughout the chapter.
Youtube Videos
Audio Book
Dive deep into the subject with an immersive audiobook experience.
Introduction to Object-Oriented Design Patterns
Unlock Audio Book
Signup and Enroll to the course for listening the Audio Book
OOP enables use of reusable patterns in software engineering:
Detailed Explanation
Object-Oriented Programming (OOP) offers a structure for creating software in a way that promotes reuse and organization. In this context, design patterns are standard solutions to common problems that arise in software design. They help developers avoid reinventing the wheel by utilizing tried-and-tested methods.
Examples & Analogies
Think of design patterns like a recipe book. Just as a chef follows specific recipes for dishes they want to prepare, software developers can use established design patterns to solve programming challenges efficiently.
Creational Patterns
Unlock Audio Book
Signup and Enroll to the course for listening the Audio Book
- Creational Patterns: Singleton, Factory, Builder
Detailed Explanation
Creational patterns focus on the process of object creation. They help control which objects to create and how to instantiate them. For example, the Singleton pattern ensures that a class has only one instance and provides a global point of access to it. The Factory pattern provides an interface for creating objects without specifying the exact class of object that will be created. The Builder pattern helps in constructing complex objects step by step.
Examples & Analogies
Imagine a toy factory. Instead of building each toy from scratch (which is inefficient), the factory has a set of blueprints (creational patterns) that outline how to build different types of toys. This way, they can easily create various toys while maintaining quality and consistency.
Structural Patterns
Unlock Audio Book
Signup and Enroll to the course for listening the Audio Book
- Structural Patterns: Adapter, Composite, Proxy
Detailed Explanation
Structural patterns deal with object composition and typically help simplify the relationships between objects. For instance, the Adapter pattern allows incompatible interfaces to work together by converting the interface of a class into another interface that a client expects. The Composite pattern lets clients treat individual objects and compositions of objects uniformly. The Proxy pattern provides a surrogate or placeholder to control access to another object.
Examples & Analogies
Consider how different devices connect to a computer. An adapter might be needed to plug a new gadget into an old computer. Similarly, in software, structural patterns facilitate interactions between different parts, ensuring they work together smoothly.
Behavioral Patterns
Unlock Audio Book
Signup and Enroll to the course for listening the Audio Book
- Behavioral Patterns: Observer, Strategy, Command
Detailed Explanation
Behavioral patterns are concerned with algorithms and how objects interact and communicate. The Observer pattern defines a one-to-many dependency between objects, so when one object changes state, all its dependents are notified. The Strategy pattern allows selecting an algorithm's behavior at runtime, while the Command pattern encapsulates a request as an object, thereby allowing parameterization of clients.
Examples & Analogies
Think about a news agency that sends out alerts for breaking news. The Observer pattern works like this: the agency notifies all journalists (observers) when news breaks. Each journalist can choose how to report it (Strategy), while the alerts themselves are structured requests (Command) that ensure the news is delivered effectively.
Definitions & Key Concepts
Learn essential terms and foundational ideas that form the basis of the topic.
Key Concepts
-
Design Patterns: Reusable solutions to common design issues in software development.
-
Creational Patterns: Focused on the creation of objects, including Singleton, Factory, and Builder patterns.
-
Structural Patterns: Deal with class and object composition, including Adapter, Composite, and Proxy patterns.
-
Behavioral Patterns: Address object interactions, including Observer, Strategy, and Command patterns.
Examples & Real-Life Applications
See how the concepts apply in real-world scenarios to understand their practical implications.
Examples
-
Singleton Pattern: An example in Java would be a ConfigurationManager class that ensures only one instance exists for managing configurations throughout the application.
-
Factory Pattern: A ShapeFactory class that creates new shapes like Circle or Square based on the provided type without exposing instantiation logic.
Memory Aids
Use mnemonics, acronyms, or visual cues to help remember key information more easily.
🎵 Rhymes Time
-
Creational helps in creation, / Structural takes care of relation, / Behavioral gives direction!
📖 Fascinating Stories
-
Imagine a chef (Creational) who prepares a dish (object) using a recipe (pattern). The chef can use different recipes (Factory pattern) based on ingredients available. Sometimes, the chef needs tools (Adapter) to work with different ingredients.
🧠 Other Memory Gems
-
Remember 'C-S-B' for 'Creational, Structural, Behavioral' patterns!
🎯 Super Acronyms
Use 'CSB' to recall the three types of design patterns
- Creational
- Structural
- Behavioral.
Flash Cards
Review key concepts with flashcards.
Glossary of Terms
Review the Definitions for terms.
-
Term: Design Pattern
Definition:
A reusable solution to a common problem in software design, providing a template on how to solve specific design issues.
-
Term: Creational Pattern
Definition:
Patterns focused on the creation of objects in a manner suitable to the situation.
-
Term: Structural Pattern
Definition:
Patterns that deal with the composition of classes or objects, defining relationships.
-
Term: Behavioral Pattern
Definition:
Patterns that define how objects interact and communicate within a system.
-
Term: Observer Pattern
Definition:
A behavioral pattern that allows one object to notify others about changes in its state.
-
Term: Adapter Pattern
Definition:
A structural pattern that allows incompatible interfaces to work together.
-
Term: Singleton Pattern
Definition:
A creational pattern that ensures a class has only one instance and provides a global point of access.