package hashCodeEquals;

/**

* if we override the equals() method, we also have to override hashCode().

*

* **/

/***

* doesn't consider only object identity but also the value of the

* amount,currencyCode properties:

**/

/**

***equals() Contract***

* equals() method must fulfill below Criteria

*

* 1. reflexive: an object must equal itself

* 2. symmetric: x.equals(y) must return the same result as y.equals(x)

* 3. transitive: if x.equals(y) and y.equals(z) then also x.equals(z)

* 4. consistent: the value of equals() should change only if a property that is contained in equals() changes (no randomness allowed)

* 5. For any non-null reference value x, x.equals(null) should return false.

* */

public class HashCodeEqualsContractMain {

public static void main(String[] args) {

Money income = new Money(55, "USD");

Money expenses = new Money(55, "USD");

// Equals Method only Consider Object(income/expenses) identity

// Object.java class equals methods compare object -> return (this == obj);

boolean balanced = income.equals(expenses);

System.out.println("income : " + income);

System.out.println("expenses : " + expenses);

System.out.println("with Default Equals Method :" + balanced);

System.out.println("***************Overriden Equals Case********************");

Money2 income2 = new Money2(55, "USD");

Money2 expenses2 = new Money2(55, "USD");

// Equals Method only Consider Object(income/expenses) identity

// Object.java class equals methods compare object -> return (this == obj);

boolean balanced2 = income2.equals(expenses2);

System.out.println("income : " + income2);

System.out.println("expenses : " + expenses2);

System.out.println("with Default Equals Method :" + balanced2);

// **********Violating equals() Symmetry With Inheritance*********

System.out.println("*************Violating equals() Symmetry With Inheritance***********");

Money2 cash = new Money2(42, "USD");

WrongVoucher voucher = new WrongVoucher(42, "USD", "Amazon");

System.out.println("Correct Result :" + voucher.equals(cash));

System.out.println("Wrong Result :" + cash.equals(voucher));

//***********Fixing equals() Symmetry With Composition*************

System.out.println("*************Fixing equals() Symmetry With Composition***********");

Money2 cash2 = new Money2(42, "USD");

Voucher voucher2 = new Voucher(42, "USD", "Amazon");

System.out.println("Correct Result :" + voucher2.equals(cash2));

System.out.println("Correct Result :" + cash2.equals(voucher2));

}

}