64 lines
1.7 KiB
Java
64 lines
1.7 KiB
Java
//: innerclasses/Factories.java
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// ©2015 MindView LLC: see Copyright.txt
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import static net.mindview.util.Print.*;
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interface Service {
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void method1();
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void method2();
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}
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interface ServiceFactory {
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Service getService();
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}
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class Implementation1 implements Service {
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private Implementation1() {}
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public void method1() {print("Implementation1 method1");}
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public void method2() {print("Implementation1 method2");}
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public static ServiceFactory factory =
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new ServiceFactory() {
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public Service getService() {
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return new Implementation1();
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}
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};
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}
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class Implementation2 implements Service {
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private Implementation2() {}
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public void method1() {print("Implementation2 method1");}
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public void method2() {print("Implementation2 method2");}
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// Use method reference instead:
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public static ServiceFactory factory =
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Implementation2::new; // Constructor reference
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}
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class Implementation3 implements Service {
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private Implementation3() {}
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public void method1() {print("Implementation3 method1");}
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public void method2() {print("Implementation3 method2");}
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// Use lambda expression instead:
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public static ServiceFactory factory =
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() -> new Implementation3();
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}
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public class Factories {
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public static void serviceConsumer(ServiceFactory fact) {
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Service s = fact.getService();
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s.method1();
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s.method2();
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}
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public static void main(String[] args) {
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serviceConsumer(Implementation1.factory);
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// Implementations are completely interchangeable:
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serviceConsumer(Implementation2.factory);
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serviceConsumer(Implementation3.factory);
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}
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} /* Output:
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Implementation1 method1
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Implementation1 method2
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Implementation2 method1
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Implementation2 method2
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Implementation3 method1
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Implementation3 method2
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*///:~
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