/*
  Author:  James Tam
  Version: Feb. 4, 2021

  Learning objective: 
  1) The application of the 'this' reference. It's an implicit
     paramter because it's automatically accessible to all non-static
     methods.
     a) With the two mutator methods: this.attribute = value will 
        differentiate the attribute from the parameter e.g.
        this.age = age;
     b) With the method when another Person object is passed as a 
        parameter: displayFriend(). The this reference makes it possible
        to know which object's method has been called.
  2) Calling other versions of a constructor via this().
*/

public class Person
{
    public static final String DEFAULT_NAME = "No name";
    public static final int DEFAULT_AGE = -1;
    private int age;
    private String name;

    public Person()
    {
        //Calls Person(String,int)
        this(DEFAULT_NAME,DEFAULT_AGE);

        //Don't do this in this particular example. Method calls itself
        //endlessly. Fortunately the Java compiler catches it for you.
        //this();
    } 

    public Person(String newName, int newAge)
    {
        setName(newName);
        setAge(newAge);
    }

     
    public void displayFriend(Person aPerson)
    {
        System.out.print("Whose display friend method: ");
        System.out.println(this.name + ", " + age);
        System.out.println(name + "'s friend is " +aPerson.name);
    }

    public int getAge()
    {
        return(age);
    }

    public String getName()
    {
        return(name);
    }

    //Logic error, this not used.
    public void notSetAge(int age)
    {
        age = age;
    }

    public void setAge(int age)
    {
        this.age = age;
    }

    public void setName(String name)
    {
        this.name = name;
    }
}