1 /*
   2  * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  *
   8  *   - Redistributions of source code must retain the above copyright
   9  *     notice, this list of conditions and the following disclaimer.
  10  *
  11  *   - Redistributions in binary form must reproduce the above copyright
  12  *     notice, this list of conditions and the following disclaimer in the
  13  *     documentation and/or other materials provided with the distribution.
  14  *
  15  *   - Neither the name of Oracle nor the names of its
  16  *     contributors may be used to endorse or promote products derived
  17  *     from this software without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
  20  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  24  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  25  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  26  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  27  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  28  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  29  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30  */
  31 
  32 /**
  33  * The sample illustrates the simplest use case of the <b>default methods</b>.
  34  *
  35  * @author Taras Ledkov
  36  */
  37 public class SimplestUsage {
  38 
  39     /**
  40      * The Animal interface provides the default implementation 
  41      * of the {@link #eat} method.
  42      */
  43     public interface Animal {
  44 
  45         /**
  46          * Return string representation of the eat action for Animal
  47          *
  48          * @return string representation of the eat action for Animal
  49          */
  50         default String eat() {
  51             return this.getClass().getSimpleName()
  52                     + " eats like an ordinary animal";
  53         }
  54     }
  55 
  56     /**
  57      * The Dog class doesn't have its own implementation of the {@link #eat} 
  58      * method and uses the default implementation.
  59      */
  60     public static class Dog implements Animal {
  61     }
  62 
  63     /**
  64      * The Mosquito class implements {@link #eat} method, its own implementation
  65      * overrides the default implementation.
  66      *
  67      */
  68     public static class Mosquito implements Animal {
  69 
  70         /**
  71          * Return string representation of the eat action for Mosquito
  72          *
  73          * @return string representation of the eat action for Mosquito
  74          */
  75         @Override
  76         public String eat() {
  77             return "Mosquito consumes blood";
  78         }
  79     }
  80 
  81     /**
  82      * Illustrate behavior of the classes: {@link Dog} and {@link Mosquito}
  83      *
  84      * @param args command-line arguments
  85      */
  86     public static void main(String[] args) {
  87         // "Dog eats like an ordinary animal" output is suspected here
  88         System.out.println(new Dog().eat());
  89 
  90         // "Mosquito consumes blood" output is suspected here
  91         System.out.println(new Mosquito().eat());
  92     }
  93 }