[Java Design Pattern] [Creational Pattern] - Factory Method

Creational Pattern - Factory Method Pattern
Purpose: The Factory Method Pattern gives us a way encapsulate the instancetiation of concrete types. Instead you delcare new direct object, you use Factory class to create a new object.

Factory Method concept UML. (Source: Software Architecture Design Patterns in Java.pdf)

Example 1:


IVehicle
package com.designpattern.creational.factorymethod;

public interface IVehicle {
    void run();
}

Vehicle
package com.designpattern.creational.factorymethod;

public class Vehicle implements IVehicle {
   
    private String color;
   
    @Override
    public void run() {
        System.out.println("Not Run");
    }

    public String getColor() {
        return color;
    }

    public void setColor(String color) {
        this.color = color;
    }
}

Bike
package com.designpattern.creational.factorymethod;

public class Bike extends Vehicle {
   
    @Override
    public void run() {
        // TODO Auto-generated method stub
        System.out.println("Bike is running...");
    }

}

Car
package com.designpattern.creational.factorymethod;

public class Car extends Vehicle {

    @Override
    public void run() {
        // TODO Auto-generated method stub
        System.out.println("Car is running...");
    }
}

Motobike

package com.designpattern.creational.factorymethod;

public class Motobike extends Vehicle {
   
    @Override
    public void run() {
        // TODO Auto-generated method stub
        System.out.println("Motobike is running...");
    }
}

VechicleFactory
package com.designpattern.creational.factorymethod;

public class VehicleFactory {

    public static Vehicle createVehicle(String s) {
        Vehicle vehicle = null;
       
        if ("bike".equals(s)) {
            vehicle = new Bike();
        } else if ("motobike".equals(s)) {
            vehicle = new Motobike();
        } else if ("car".equals(s)) {
            vehicle = new Car();
        } else {
            vehicle = new Vehicle();
        }

        return vehicle;

    }
}

VehicleMain
package com.designpattern.creational.factorymethod;

public class VehicleMain {
    public static void main(String[] args) {
        Vehicle bike =   VehicleFactory.createVehicle("bike");
        bike.run();
      
        Vehicle motobike = VehicleFactory.createVehicle("motobike");
        motobike.run();
      
        Vehicle car = VehicleFactory.createVehicle("car");
        car.run();

    }
}

Result:
Bike is running...
Motobike is running...
Car is running...