OnJava8-Examples/equalshashcode/SubtypeEquality2.java at master · CSapprenticeWT/OnJava8-Examples · GitHub

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// equalshashcode/SubtypeEquality2.java

// We make no guarantees that this code is fit for any purpose.

// Visit http://OnJava8.com for more book information.

import java.util.*;

class Dog2 extends Animal {

Dog2(String name, Size size) {

super(name, size);

}

@Override public boolean equals(Object rval) {

return rval instanceof Dog2 &&

super.equals(rval);

}

class Pig2 extends Animal {

Pig2(String name, Size size) {

super(name, size);

}

@Override public boolean equals(Object rval) {

return rval instanceof Pig2 &&

super.equals(rval);

}

public class SubtypeEquality2 {

public static void main(String[] args) {

Set<Animal> pets = new HashSet<>();

pets.add(new Dog2("Ralph", Size.MEDIUM));

pets.add(new Pig2("Ralph", Size.MEDIUM));

pets.forEach(System.out::println);

}

/* Output:

Dog2[0]: Ralph MEDIUM 931523a9

Pig2[1]: Ralph MEDIUM 931523a9