Mastering Java Design Patterns - Day 19: Strategy Pattern

Hello, developers! We're nearing the end of our journey through Java Design Patterns. Today, we delve into the Strategy Pattern, a fundamental pattern for scenarios where multiple algorithms might be chosen dynamically during runtime.

What is the Strategy Pattern?

The Strategy Pattern defines a family of algorithms, encapsulates each one, and makes them interchangeable. This pattern lets the algorithm vary independently from clients that use it. It’s particularly useful for applications that require dynamic decision-making about which algorithm to use at runtime.

Why Use the Strategy Pattern?

• Flexibility: It provides a way to switch between different algorithms in runtime without altering the client.
• Decoupling: It helps in decoupling the algorithm from where it is used, making the system easier to understand and maintain.
• Scalability: Adding new strategies becomes straightforward without impacting existing code.

How to Implement the Strategy Pattern in Java

Here’s how you can implement the Strategy Pattern:

// Strategy interface

interface SortingStrategy {

    void sort(List<Integer> list);

}        

// Concrete Strategies

class QuickSort implements SortingStrategy {

    public void sort(List<Integer> list) {
        System.out.println("Sorting using quick sort");
        // Quick sort algorithm
    }

}        

// Concrete Strategies

class MergeSort implements SortingStrategy {

    public void sort(List<Integer> list) {
        System.out.println("Sorting using merge sort");
        // Merge sort algorithm
    }

}        

// Context

class SortedList {

    private SortingStrategy strategy;

    public void setSortingStrategy(SortingStrategy strategy) {
        this.strategy = strategy;
    }

    public void sort(List<Integer> list) {
        strategy.sort(list);
    }

}        

// Client code

public class StrategyPatternDemo {

    public static void main(String[] args) {

        SortedList list = new SortedList();

        List<Integer> numbers = Arrays.asList(5, 2, 9, 1, 5, 6);

        list.setSortingStrategy(new QuickSort());

        list.sort(numbers);

        list.setSortingStrategy(new MergeSort());

        list.sort(numbers);

    }

}        

Discussion:

Have you used the Strategy Pattern to implement different algorithms or functionalities in your projects? What benefits have you observed from using this pattern? Share your experiences and insights in the comments below!

?? Call to Action: If you found this overview helpful, please like, share, and comment! Follow #ehadjistratis for more engaging discussions on Java Design Patterns and professional development in software engineering.

I look forward to your engaging stories and insights!

Stay tuned for tomorrow's topic: Template Method Pattern.

#Java #DesignPatterns #StrategyPattern #Programming #Coding #SoftwareDevelopment #LearningJourney #JuniorDevelopers #TechCommunity #ehadjistratis