Java abstract factory design pattern

Java abstract factory design pattern is one level higher than the factory design pattern. It comes under the Creational Design Pattern category.

In abstract factory design pattern a super factory is responsible to create other factories of related objects. A factory will be created from a super factory class without exposing the creation logic to the client. Now, this factory will be responsible to create the objects based on Factory Design Pattern.

Main advantage of factory design pattern is it provides the loose-coupling.

Let’s look at the abstract factory design pattern with below example. We are taking here an example of two different entity types like Shape and Color. We will create two interfaces Shape and Color which will be implemented by corresponding sub classes. We will create AbstractFactory class. Next, create ShapeFactory and ColorFactory classes which will extends the AbstractFactory. A FactoryGenerator class is created to get the factory object. ShapeFactory is responsible to create different shapes like Circle, Rectangle and Square. ColorFactory is responsible to create different colors like Green, Red, Blue.

Example

Shape.java

package com.w3spoint;
 
public interface Shape {
	void drawShape();
}

Circle.java

package com.w3spoint;
 
public class Circle implements Shape {
	@Override
	public void drawShape() {
		System.out.println("Shape Circle.");
	}
}

Rectangle.java

package com.w3spoint;
 
public class Rectangle implements Shape {
	@Override
	public void drawShape() {
		System.out.println("Shape Rectangle.");
	}
}

Square.java

package com.w3spoint;
 
public class Square implements Shape {
	@Override
	public void drawShape() {
		System.out.println("Shape Square.");
	}
}

Color.java

package com.w3spoint;
 
public interface Color {
	void fillColor();
}

Blue.java

package com.w3spoint;
 
public class Blue implements Color {
	@Override
	public void fillColor() {
		System.out.println("Fill Blue Color.");
	}
}

Green.java

package com.w3spoint;
 
public class Green implements Color {
	@Override
	public void fillColor() {
		System.out.println("Fill Green Color.");
	}
}

Red.java

package com.w3spoint;
 
public class Red implements Color {
	@Override
	public void fillColor() {
		System.out.println("Fill Red Color.");
	}
}

AbstractFactory.java

package com.w3spoint;
 
public abstract class AbstractFactory {
	abstract Color getColor(String color);
	abstract Shape getShape(String shape);
}

ShapeFactory.java

package com.w3spoint;
 
public class ShapeFactory extends AbstractFactory{
 
   //getShape method returns object of input type shape
   @Override
   public Shape getShape(String shapeType){
      if(shapeType == null){
         return null;
      }		
      if(shapeType.equalsIgnoreCase("Circle")){
         return new Circle();
 
      } else if(shapeType.equalsIgnoreCase("Rectangle")){
         return new Rectangle();
 
      } else if(shapeType.equalsIgnoreCase("Square")){
         return new Square();
      }
 
      return null;
   }
 
   @Override
   Color getColor(String color) {
      return null;
   }
}

ColorFactory.java

package com.w3spoint;
 
public class ColorFactory extends AbstractFactory{	 
   //getColor method returns object of input type color
   @Override
   Color getColor(String color) {   
      if(color == null){
         return null;
      }		
 
      if(color.equalsIgnoreCase("Red")){
         return new Red();
 
      }else if(color.equalsIgnoreCase("Green")){
         return new Green();
 
      }else if(color.equalsIgnoreCase("Blue")){
         return new Blue();
      }
 
      return null;
   }
 
   @Override
   public Shape getShape(String shapeType){
      return null;
   }
}

FactoryGenerator.java

package com.w3spoint;
 
public class FactoryGenerator {
   public static AbstractFactory getFactory(String choice){		   
      if(choice.equalsIgnoreCase("Shape")){
         return new ShapeFactory();
 
      }else if(choice.equalsIgnoreCase("Color")){
         return new ColorFactory();
      }
 
      return null;
   }
}

AbstractFactoryPatternTest.java

package com.w3spoint;
 
 
public class AbstractFactoryPatternTest {
	public static void main(String args[]){
	      //get color factory
	      AbstractFactory shapeFactory = FactoryGenerator.getFactory("Shape");
 
	      //Get Circle class object
	      Shape shape1 = shapeFactory.getShape("Circle");
 
	      //call drawShape method of Circle
	      shape1.drawShape();
 
	      //Get Rectangle class object
	      Shape shape2 = shapeFactory.getShape("Rectangle");
 
	      //call drawShape method of Rectangle
	      shape2.drawShape();
 
	      //Get Square class object
	      Shape shape3 = shapeFactory.getShape("Square");
 
	      //call drawShape method of Square
	      shape3.drawShape();
 
	      //get color factory
	      AbstractFactory colorFactory = FactoryGenerator.getFactory("Color");
 
	      //get an object of Color Red
	      Color color1 = colorFactory.getColor("Red");
 
	      //call fillColor method of Red
	      color1.fillColor();
 
	      //get an object of Color Green
	      Color color2 = colorFactory.getColor("Green");
 
	      //call fillColor method of Green
	      color2.fillColor();
 
	      //get an object of Color Blue
	      Color color3 = colorFactory.getColor("Blue");
 
	      //call fillColor method of Color Blue
	      color3.fillColor();
	}
}

Output

Shape Circle.
Shape Rectangle.
Shape Square.
Fill Red Color.
Fill Green Color.
Fill Blue Color.

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