Factory Design Pattern

Main.Java

public class Main {

    public static void main(String[] args) {
        ShapeFactory shapeFactory = new ShapeFactory();

        Shape shape1 = shapeFactory.getShape("TRIANGLE");
        shape1.draw();

        Shape shape2 = shapeFactory.getShape("RECTANGLE");
        shape2.draw();

        Shape shape3 = shapeFactory.getShape("SQUARE");
        shape3.draw();
    }

}

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ShapeFactory.Java

public class ShapeFactory {
    public Shape getShape(String shapeType){
        if(shapeType == null){
            return null;
        }
        else if(shapeType.equalsIgnoreCase("RECTANGLE")){
            return new Rectangle();
        }
        else if(shapeType.equalsIgnoreCase("SQUARE")){
            return new Square();
        }
        else if(shapeType.equalsIgnoreCase("TRIANGLE")){
            return new Triangle();
        }

        return null;
    }
}

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Triangle.Java

public class Triangle implements Shape{

    @Override
    public void draw() {
        System.out.println("This is draw in Triangle");
    }

}

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Square.Java

public class Square implements Shape{

    @Override
    public void draw() {
        System.out.println("This is draw in Sqaure");
    }

}

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Rectangle.Java

public class Rectangle implements Shape{

    @Override
    public void draw() {
        System.out.println("This is draw from Rectangle");
    }

}

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Shape.Java

public interface Shape {
    public void draw();
}