package dk.itu.oop.lecture5;

public class CarPersonTest{
	public static void main (String[] args){
		Car c = new Car("Ford", new Person("Jack"));
		System.out.println(c);
	}
}

class Car{
	/* inv: owner != null, and owner.myCar == this*/
	private Person owner;
	private String make;
	/* pre: owner.myCar == null
	   post: owner.myCar = this.
	*/
	public Car(String make, Person owner){
		this.make = make;
		this.owner = owner;
		owner.setCar(this);
	}
	/* pre: owner.myCar == null
	   post: owner.myCar == this
	*/
	public void setOwner(Person owner){
		this.owner.setCar(null);
		this.owner = owner;
		owner.setCar(this);
	}
	public String toString(){
		return make +" owned by " + owner;
	}
}

class Person{
	/* inv: if myCar != null, myCar.owner = this.*/
	private Car myCar;
	private String name;
	Person(String name){
		this.name = name;
	};
	/* pre: myCar == null, c.owner = this
	    post: inv
	*/
	public void setCar(Car c){
		myCar = c;
	}
	public String toString(){
		return "Person " + name;
	}
}