// interfaces/Factories.java
// (c)2017 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.

interface Service {
 void method1();
 void method2();
}

interface ServiceFactory {
 Service getService();
}

class Service1 implements Service {
 Service1() {} // Package access
 public void method1() {
 System.out.println("Service1 method1");
 }
 public void method2() {
 System.out.println("Service1 method2");
 }
}

class Service1Factory implements ServiceFactory {
 @Override
 public Service getService() {
 return new Service1();
 }
}

class Service2 implements Service {
 Service2() {} // Package access
 public void method1() {
 System.out.println("Service2 method1");
 }
 public void method2() {
 System.out.println("Service2 method2");
 }
}

class Service2Factory implements ServiceFactory {
 @Override
 public Service getService() {
 return new Service2();
 }
}

public class Factories {
 public static void
 serviceConsumer(ServiceFactory fact) {
 Service s = fact.getService();
 s.method1();
 s.method2();
 }
 public static void main(String[] args) {
 serviceConsumer(new Service1Factory());
 // Services are completely interchangeable:
 serviceConsumer(new Service2Factory());
 }
}
/* Output:
Service1 method1
Service1 method2
Service2 method1
Service2 method2
*/