Java: using setter of a subclass when creating an object of type Superclass

Question

I have a superclass Person and two subclasses Man and Woman

in subclass Man, I have an instance variable age:

public class Man extends Person{

   private double age;

   public final static double MIN_AGE = 0.0;
   public final static double MAX_AGE = 65.0;

  //no argument constructor
  public Man(){
    super();
    initAge();  // This randomly selects age
  }

   /* Setters and getters */
   public void setAge (double ageIn) 
   {
      /* Assign a value only if it is within the allowed range */
      if (ageIn>= MIN_AGE && ageIn<= MAX_AGE )
      {
        this.age = ageIn;
      }
      else if (ageIn< MIN_AGE)
      {
        this.age = MIN_AGE;
      }
      else if (ageIn > MAX_AGE)
      {
        this.age = MAX_AGE;
      }
   }

  public double getAge()
  {
    return age;
  }
}

Now, my task is to create a Man object and test whether the setter works and whether initAge works by showing the value of "age: with getAge.

I also have to initialize the object using the following:

Person p1 = new Man();

However, if initialized this way, I do not have access to Man's setters and getters. Is there a way around this other than doing:

Man p1 = new Man();

Thanks!

hoat4 · Accepted Answer · 2015-02-07 19:46:30Z

1

Cast p1 to Man:

((Man) p1).setAge(13);

answered Feb 7, 2015 at 19:46

hoat4

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Giancarlo Romeo · Accepted Answer · 2015-02-07 19:50:58Z

1

You can add abstract methods to the Person class:

public abstract class Person {

    public abstract double getAge();
    public abstract setAge(double ageIn);
}

Or, if the methods are sex-independent, move them to the parent, so Man and Woman can inherit.

answered Feb 7, 2015 at 19:50

Giancarlo Romeo

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2 Comments

Igor Tupitsyn Over a year ago

Thank you. A good idea but I must not change the superclass. Thanks for the help, anyways!

Giancarlo Romeo Over a year ago

In this case, if you are SURE the reference is a Man object, the only thing you can do is to use a cast. if (p1 instanceof Man) ((Man) p1).setAge(42);

user3377716 · Accepted Answer · 2015-02-07 19:55:28Z

1

You're going to have to use Person p1 = new Man(); because that's the only way if you really do not want to create a Man object of an instantiated new Man().

Now in order to access the setters and getters as a Person, you would need to mask that by casting the Man type over it.

((Man) p1).setAge(double)

answered Feb 7, 2015 at 19:55

user3377716

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