/*
 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 */


import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Arrays;

/**
 * The code sample illustrates changes in reflection API linked
 * <b>default methods</b>. Since Java SE 8, a new method is added into class
 * <b><code>java.lang.reflect.Method</code></b>, with which we could
 * reflectively determine if a method is a default method provided by an
 * interface or not (<b><code>Method.isDefault()</code></b>).
 */
public class Reflection {

     /** Base interface to illustrate new reflection API.
      * 
      * @see Dog
      */
    public interface Animal {

        default void eat() {
            System.out.println(this.getClass().getSimpleName() + " eats like an ordinary animal");
        }

        default void sleep() {
            System.out.println(this.getClass().getSimpleName() + " sleeps like an ordinary animal");
        }

        void go();
    }

    /**
     * Dog class to illustrate new reflection API. We can see that:
     * <ul>
     * <li> the {@link #go} and {@link #sleep} methods are not default.
     * {@link #go} has not default implementation and {@link #sleep} method
     * implementation wins as subtype (according with {@link Inheritance} rule
     * 2) </li>
     * <li> the {@link #eat} is a simple default method that not overridden 
     * in this class.
     * </li>
     * </ul>
     */
    public static class Dog implements Animal {

        @Override
        public void go() {
            System.out.println("Dog walks on four legs");
        }

        @Override
        public void sleep() {
            System.out.println("Dog sleeps");
        }
    }

    public static void main(String[] args) throws NoSuchMethodException {
        Method[] methods = {Dog.class.getMethod("eat"), Dog.class.getMethod("go"), Dog.class.getMethod("sleep")};
        final Dog dog = new Dog();

        Arrays.asList(methods).stream().forEach((m) -> {
            System.out.println("Method name:   " + m.getName());
            System.out.println("    isDefault: " + m.isDefault());
            System.out.print("    invoke:    ");
            try {
                m.invoke(dog);
            } catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException ex) {
            }
            System.out.println();
        });
    }
}