Java Design Patterns: Modern Solutions for Common Problems [COMPLETED]

Welcome to the Java Design Patterns: Modern Solutions GitHub repository! Here, we explore how design patterns have evolved in Java, leveraging the language's maturation and modern capabilities.

In this repository, we showcase updated approaches to common design problems using Java's native features. We cover patterns like Singleton, Builder, Strategy, Observer, and Decorator. By utilizing Java's advancements, we eliminate boilerplate code and enhance readability, flexibility, and maintainability.

Join us to learn and apply these modern design patterns in Java. Elevate your software design skills and create robust code effortlessly. Let's revolutionize the way we solve problems together!

Table of Contents

• Design and Design Patterns
• Optional: Patterns and Anti-patterns
• Iterator Pattern
• Lightweight Strategy
• Factory Method using Default Methods
• Laziness using Lambda Expressions
• Decorator using Lambda Expressions
• Creating Fluent Interfaces
• Execute Around Method Pattern

Design and Design Patterns

In this section, we will introduce the concepts of design and design patterns. Understanding the importance of design patterns in software development will lay a solid foundation for the rest of the topics covered in this repository.

Optional: Patterns and Anti-patterns

The Optional class in Java provides a way to handle nullable values. In this section, we will explore different patterns and anti-patterns related to using the Optional class effectively in our code.

How to Use Optional

1. Rule #1: Never, ever use null for an optional variable or return value: Instead of using null, use Optional to indicate that a value may be absent or not available. This helps to avoid null pointer exceptions and improves code readability.

2. Rule #2: Never use Optional.get() unless you can prove that the Optional is present: Using get() directly on an Optional without checking for the presence of a value can lead to a NoSuchElementException. Always use alternative methods provided by Optional to handle the absence of a value.

3. Rule #3: Prefer alternatives to Optional.isPresent() and Optional.get(): Instead of explicitly calling isPresent() followed by get(), consider using orElse(), orElseGet(), or orElseThrow() to provide default values or custom error handling when a value is absent.

4. Rule #4: It’s generally a bad idea to create an Optional for the specific purpose of chaining methods from it to get a value: Avoid wrapping non-null objects in Optional solely for method chaining purposes. Instead, use Optional when a value is genuinely optional or to represent the absence of a value.

5. Rule #5: If an Optional chain is nested or has an intermediate result of Optional<Optional<T>>, it’s probably too complex: Nested Optional chains can lead to unreadable code and reduced maintainability. Consider simplifying the code by using alternative approaches, such as flatMap or other control flow constructs.

6. Rule #6: Avoid using Optional in fields, method parameters, and collections: Using Optional in these scenarios can introduce unnecessary complexity and reduce code clarity. Instead, use Optional for return types or when explicitly handling optional values.

7. Rule #7: Avoid using identity-sensitive operations on Optionals: Identity-sensitive operations like == or != may not behave as expected when used with Optional. Instead, use `

Iterator Pattern

The Iterator pattern allows us to iterate over a collection of objects without exposing its underlying representation. We will dive into the implementation details of the Iterator pattern and demonstrate how it can be leveraged in a functional programming context.

Lightweight Strategy

The Strategy pattern enables us to select an algorithm dynamically. By applying functional programming concepts, we can create lightweight strategies that provide flexible behavior implementation.

Factory Method using Default Methods

The Factory Method pattern is a creational pattern that provides an interface for creating objects but lets subclasses decide which class to instantiate. We will leverage the default methods introduced in Java 8 to implement the Factory Method pattern in a more concise and elegant way.

Laziness using Lambda Expressions

Lazy evaluation is a powerful concept in functional programming that allows computations to be deferred until their results are actually needed. Using lambda expressions and functional programming techniques, we will explore how laziness can be achieved effectively in Java 8.

Decorator using Lambda Expressions

The Decorator pattern provides a way to dynamically add new behavior to objects at runtime. In this section, we will demonstrate how to implement the Decorator pattern using lambda expressions, enabling more flexible and concise code.

Creating Fluent Interfaces

Fluent interfaces enhance the readability and expressiveness of code by providing a fluent and method-chaining style of constructing objects. We will discuss the concept of fluent interfaces and how they can be created using Java 8 functional programming features.

Execute Around Method Pattern

The Execute Around Method pattern allows a method to control the execution of a block of code. We will explore the implementation of this pattern using functional programming techniques, leveraging the power of lambda expressions and higher-order functions.

We hope this repository provides you with a deep understanding of design patterns and their implementation using Java 8 functional programming. Each topic will be covered in a detailed manner, with code examples and explanations to facilitate your learning journey. Feel free to explore the code, experiment with the examples, and expand your knowledge of design patterns in a functional programming context.

Happy learning!