This is the flow of the Abstract factory pattern.Its implemented in java
//create a shape interface and implementer classes shape
public interface Shape {
void draw();
}
public class Rectangle implements Shape {
@Override
public void draw() {
System.out.println("Inside Rectangle::draw() method.");
}
}
public class Square implements Shape {
@Override
public void draw() {
System.out.println("Inside Square::draw() method.");
}
}
//create color interface and its implementers
public interface Color {
void fill();
}
public class Red implements Color {
@Override
public void fill() {
System.out.println("Inside Red::fill() method.");
}
}
public class Blue implements Color {
@Override
public void fill() {
System.out.println("Inside Blue::fill() method.");
}
}
//create abstract factory class that is generally a class that generates the interfaces or in easy language a factory that can manufacture anything you ask of it
public abstract class AbstractFactory {
abstract Color getColor(String color);
abstract Shape getShape(String shape) ;
}
//create shape factory just like you know normal factories manufacture things. This is the factory that manufactures shapes.you just give it the name of the shape you want and it will manufacture it
public class ShapeFactory extends AbstractFactory {
@Override
public Shape getShape(String shapeType){
if(shapeType == null){
return null;
}
if(shapeType.equalsIgnoreCase("RECTANGLE")){
return new Rectangle();
}else if(shapeType.equalsIgnoreCase("SQUARE")){
return new Square();
}
return null;
}
@Override
Color getColor(String color) {
return null;
}
}
//color factory .This is the factory that manufactures colors . you just give it the name of the color you want and it will manufacture it
public class ColorFactory extends AbstractFactory {
@Override
public Shape getShape(String shapeType){
return null;
}
@Override
Color getColor(String color) {
if(color == null){
return null;
}
if(color.equalsIgnoreCase("RED")){
return new Red();
}else if(color.equalsIgnoreCase("BLUE")){
return new Blue();
}
return null;
}
}
//produces factories .Now this class is like an investor who constructs factories . give it the name and it will construct for you the factory that manufactures that.
public class FactoryProducer {
public static AbstractFactory getFactory(String choice){
if(choice.equalsIgnoreCase("SHAPE")){
return new ShapeFactory();
}else if(choice.equalsIgnoreCase("COLOR")){
return new ColorFactory();
}
return null;
}
}
//This is the demo class like the dealer who would request an investor to construct a shape factory
and this factory can then manufacture rectangles, squares etc.
public class AbstractFactoryPatternDemo {
public static void main(String[] args) {
//get shape factory
AbstractFactory shapeFactory = FactoryProducer.getFactory("SHAPE");
//get an object of Shape Rectangle
Shape shape2 = shapeFactory.getShape("RECTANGLE");
//call draw method of Shape Rectangle
shape2.draw();
//get an object of Shape Square
Shape shape3 = shapeFactory.getShape("SQUARE");
//call draw method of Shape Square
shape3.draw();
//get color factory
AbstractFactory colorFactory = FactoryProducer.getFactory("COLOR");
//get an object of Color Red
Color color1 = colorFactory.getColor("RED");
//call fill method of Red
color1.fill();
//get an object of Color Blue
Color color3 = colorFactory.getColor("BLUE");
//call fill method of Color Blue
color3.fill();
}
}
