Design Patterns in Low Level Design

Design patterns provide proven solutions to common problems in software design. They are reusable solutions that can be applied to different scenarios. In low level design, design patterns help in structuring the code and making it more maintainable and flexible.

One commonly used design pattern in low level design is the Singleton pattern. This pattern ensures that only one instance of a class is created throughout the runtime of the application. It is useful in situations where a single instance of a class is required to be shared across different parts of the application.

Here is an example of implementing the Singleton pattern in Java:

1public class Singleton {
2  private static Singleton instance;
3
4  private Singleton() {}
5
6  public static Singleton getInstance() {
7    if (instance == null) {
8      instance = new Singleton();
9    }
10    return instance;
11  }
12
13  // Other methods
14}

In the above code, the getInstance() method ensures that only one instance of the Singleton class is created.

Another common design pattern in low level design is the Factory pattern. This pattern is used to create objects without exposing the instantiation logic to the client. It provides a way to create objects of various types based on a common interface.

Here is an example of implementing the Factory pattern in Java:

1public interface Shape {
2  void draw();
3}
4
5public class Circle implements Shape {
6  @Override
7  public void draw() {
8    System.out.println("Drawing a circle");
9  }
10}
11
12public class Rectangle implements Shape {
13  @Override
14  public void draw() {
15    System.out.println("Drawing a rectangle");
16  }
17}
18
19public class ShapeFactory {
20  public Shape createShape(String shapeType) {
21    if (shapeType.equals("circle")) {
22      return new Circle();
23    } else if (shapeType.equals("rectangle")) {
24      return new Rectangle();
25    }
26    return null;
27  }
28}

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class Main {

  public static void main(String[] args) {

    // Replace with your Java logic here

    System.out.println("Hello, world!");

  }

}