Strategies design pattern

 

Components of the Strategy Design Pattern

Components-of-Strategy-Design-Pattern-

1. Context

A class or object known as the Context assigns the task to a strategy object and contains a reference to it.

  • It serves as an intermediary between the client and the strategy, offering an integrated approach for task execution without exposing every detail of the process.
  • The Context maintains a reference to a strategy object and calls its methods to perform the task, allowing for interchangeable strategies to be used.

2. Strategy Interface

An abstract class or interface known as the Strategy Interface specifies a set of methods that all concrete strategies must implement.

  • As a kind of agreement, it guarantees that all strategies follow the same set of rules and are interchangeable by the Context.
  • The Strategy Interface promotes flexibility and modularity in the design by establishing a common interface that enables decoupling between the Context and the specific strategies.

3. Concrete Strategies

Concrete Strategies are the various implementations of the Strategy Interface. Each concrete strategy provides a specific algorithm or behavior for performing the task defined by the Strategy Interface.

  • Concrete strategies encapsulate the details of their respective algorithms and provide a method for executing the task.
  • They are interchangeable and can be selected and configured by the client based on the requirements of the task.

4. Client

The Client is responsible for selecting and configuring the appropriate strategy and providing it to the Context.

  • It knows the requirements of the task and decides which strategy to use based on those requirements.
  • The client creates an instance of the desired concrete strategy and passes it to the Context, enabling the Context to use the selected strategy to perform the task.

StrategyDesignPatternExample

Below is the implementation of the above example:

1. Strategy Interface(SortingStrategy)

public interface SortingStrategy {
    void sort(int[] array);
}



2. Context(SortingContext)
public class SortingContext {
    private SortingStrategy sortingStrategy;

    public SortingContext(SortingStrategy sortingStrategy) {
        this.sortingStrategy = sortingStrategy;
    }

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

    public void performSort(int[] array) {
        sortingStrategy.sort(array);
    }
}


3. Concrete Strategies
// BubbleSortStrategy
public class BubbleSortStrategy implements SortingStrategy {
    @Override
    public void sort(int[] array) {
        // Implement Bubble Sort algorithm
        System.out.println("Sorting using Bubble Sort");
    }
}

// MergeSortStrategy
public class MergeSortStrategy implements SortingStrategy {
    @Override
    public void sort(int[] array) {
        // Implement Merge Sort algorithm
        System.out.println("Sorting using Merge Sort");
    }
}

// QuickSortStrategy
public class QuickSortStrategy implements SortingStrategy {
    @Override
    public void sort(int[] array) {
        // Implement Quick Sort algorithm
        System.out.println("Sorting using Quick Sort");
    }
}

4. Client Component
public class Client {
    public static void main(String[] args) {
        // Create SortingContext with BubbleSortStrategy
        SortingContext sortingContext = new SortingContext(new BubbleSortStrategy());
        int[] array1 = {5, 2, 9, 1, 5};
        sortingContext.performSort(array1); // Output: Sorting using Bubble Sort

        // Change strategy to MergeSortStrategy
        sortingContext.setSortingStrategy(new MergeSortStrategy());
        int[] array2 = {8, 3, 7, 4, 2};
        sortingContext.performSort(array2); // Output: Sorting using Merge Sort

        // Change strategy to QuickSortStrategy
        sortingContext.setSortingStrategy(new QuickSortStrategy());
        int[] array3 = {6, 1, 3, 9, 5};
        sortingContext.performSort(array3); // Output: Sorting using Quick Sort
    }
}

Output
Sorting using Bubble Sort
Sorting using Merge Sort
Sorting using Quick Sort


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