Design Pattern: Abstract Factory Pattern in Java

Abstract Factory pattern is used to generate multiple factory generators.

Check complete details and explanations about the Abstract Factory pattern in the article: Abstract Factory Design Pattern

This article demonstrates Abstract Factory pattern implementations in Java. Check the following examples.

Example #1: Transport

Let’s take the example of a transport system. Take a look at the class diagram first.

Transport Factory Interface

// Transport.java

package com.bigboxcode;

public interface Transport {

    void start();

    void stop();

    void repair();

}

Bicycle Class

// Bicycle.java

package com.bigboxcode;

public class Bicycle implements Transport {
    @Override
    public void start() {
        System.out.println("Bicycle Started");
    }

    @Override
    public void stop() {
        System.out.println("Bicycle Stopped");
    }

    @Override
    public void repair() {
        System.out.println("Bicycle Repair");
    }
}

Motorcycle Class

// Motorcycle.java

package com.bigboxcode;

public class Motorcycle implements Transport {
    @Override
    public void start() {
        System.out.println("Motorcycle Started");
    }

    @Override
    public void stop() {
        System.out.println("Motorcycle Stopped");
    }

    @Override
    public void repair() {
        System.out.println("Motorcycle Repair");
    }
}

Car Class

// Car.java

package com.bigboxcode;

public class Car implements Transport {
    @Override
    public void start() {
        System.out.println("Car Started");
    }

    @Override
    public void stop() {
        System.out.println("Car Stopped");
    }

    @Override
    public void repair() {
        System.out.println("Car Repair");
    }
}

Truck Class

// Truck.java

package com.bigboxcode;

public class Truck implements Transport {
    @Override
    public void start() {
        System.out.println("Truck Started");
    }

    @Override
    public void stop() {
        System.out.println("Truck Stopped");
    }

    @Override
    public void repair() {
        System.out.println("Truck Repair");
    }
}

Abstract Transport Factory Interface

// AbstractTransportFactory.java

package com.bigboxcode;

public interface AbstractTransportFactory {

    Transport getTransport(String type);
}

Two Wheel Transport Factory Class

// TwoWheelTransportFactory.java

package com.bigboxcode;

public class TwoWheelTransportFactory implements AbstractTransportFactory{
    @Override
    public Transport getTransport(String type) {

        if (type.equalsIgnoreCase("bicycle")) {
            return new Bicycle();
        }

        if (type.equalsIgnoreCase("motorcycle")) {
            return new Motorcycle();
        }

        return null;
    }
}

Four Wheel Transport Factory Class

// FourWheelTransportFactory.java

package com.bigboxcode;

public class FourWheelTransportFactory implements AbstractTransportFactory{
    @Override
    public Transport getTransport(String type) {

        if (type.equalsIgnoreCase("car")) {
            return new Car();
        }

        if (type.equalsIgnoreCase("truck")) {
            return new Truck();
        }

        return null;
    }
}

Factory Producer Class

// FactoryProducer.java

package com.bigboxcode;

public class FactoryProducer {

    public static AbstractTransportFactory getFactory(int numberOfWheels) {

        if (numberOfWheels == 2) {
            return new TwoWheelTransportFactory();
        }

        if (numberOfWheels == 4) {
            return new FourWheelTransportFactory();
        }

        return null;
    }
}

Demo

// Main.java

package com.bigboxcode;

public class Main {

    public static void main(String[] args) {

        AbstractTransportFactory transportFactory1 = FactoryProducer.getFactory(2);
        Transport transport1 = transportFactory1.getTransport("bicycle");

        transport1.start();

        AbstractTransportFactory transportFactory2 = FactoryProducer.getFactory(4);
        Transport transport2 = transportFactory2.getTransport("truck");

        transport2.start();
    }
}

Output

Bicycle Started
Truck Started