// reflection/Position.java

// (c)2021 MindView LLC: see Copyright.txt

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

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

import java.util.*;

class EmptyTitleException extends RuntimeException {}

class Position {

private String title;

private Person person;

Position(String jobTitle, Person employee) {

setTitle(jobTitle);

setPerson(employee);

}

Position(String jobTitle) {

this(jobTitle, null);

}

public String getTitle() { return title; }

public void setTitle(String newTitle) {

// Throws EmptyTitleException if newTitle is null:

title = Optional.ofNullable(newTitle)

.orElseThrow(EmptyTitleException::new);

}

public Person getPerson() { return person; }

public void setPerson(Person newPerson) {

// Uses empty Person if newPerson is null:

person = Optional.ofNullable(newPerson)

.orElse(new Person());

}

@Override public String toString() {

return "Position: " + title +

", Employee: " + person;

}

public static void main(String[] args) {

System.out.println(new Position("CEO"));

System.out.println(new Position("Programmer",

new Person("Arthur", "Fonzarelli")));

try {

new Position(null);

} catch(Exception e) {

System.out.println("caught " + e);

}

}

}

/* Output:

Position: CEO, Employee: <Empty>

Position: Programmer, Employee: Arthur Fonzarelli

caught EmptyTitleException

*/