package com.iluwatar.value.object; /** * A Value Object are objects which follow value semantics rather than reference semantics. This * means value objects' equality are not based on identity. Two value objects are equal when they * have the same value, not necessarily being the same object.. * * Value Objects must override equals(), hashCode() to check the equality with values. * Value Objects should be immutable so declare members final. * Obtain instances by static factory methods. * The elements of the state must be other values, including primitive types. * Provide methods, typically simple getters, to get the elements of the state. * A Value Object must check equality with equals() not == * * For more specific and strict rules to implement value objects check the rules from Stephen * Colebourne's term VALJO : http://blog.joda.org/2014/03/valjos-value-java-objects.html */ public class App { /** * This practice creates three HeroStats(Value object) and checks equality between those. */ public static void main(String[] args) { HeroStat statA = HeroStat.valueOf(10, 5, 0); HeroStat statB = HeroStat.valueOf(10, 5, 0); HeroStat statC = HeroStat.valueOf(5, 1, 8); System.out.println(statA.toString()); System.out.println("Is statA and statB equal : " + statA.equals(statB)); System.out.println("Is statA and statC equal : " + statA.equals(statC)); } }