CODEWITHSUNDEEP
javainheritancesuperclass
joseph
joseph

Reputation: 917

Inheritance and subclasses basics

I'm new to creating subclasses and do not know how I can "restrain" the functionality of the subclass although I'm using the superclasses' functionality.

In my subclass, I want to use the getCash() method in my superclass, but I only want it to give me a result, if there has been more than 5 days since the date stored in my subclass. My code looks like this:

public class Super{

    private double cash;

    public Super(double cash){
        this.cash = cash;
    }

    public void deposit(double amount) {
        if (amount > 0){
            this.cash += amount;
        }
    }

    public double getCash(){
        if (this.cash > 0){
            return this.cash;
        }else {
            return 0;
        }
    }
}

public class Sub extends Super {

    private LocalDate date;

    public Sub(double cash) {
        super(cash);
    }
}

Is this the right way of attacking the problem? Or should I implement all the logic needed in my superclass, and just pass a variable telling it wether it's the superclass or the subclass calling the function? What is the best practice?

Thank you in advance.

Upvotes: 1

Views: 94

Answers (2)

Charles Follet
Charles Follet

Reputation: 817

You can use polymorphism to redefine functions in a subclass.
The function needs to have the same same signature (name + parameters).

public class Sub extends Super {

private LocalDate date;

  public Sub(double cash) {
    super(cash);
   }

  public double getCash() {
  if (/* your date check */) {
     return super.getCash();  
    }
   return 0.0;
  }
}

Thanks to shikjohari.
See : JAVA Polymorphism

Upvotes: 1

shikjohari
shikjohari

Reputation: 2288

The behaviour of returning only when the date difference is of 5 days is your subclass's behaviour so you have to write that condition in subclass only, However after the condition check you can call the super.getCash()

I think you can use the method in your subclass as 

public double getCash() {
    if (/* your date check 8*/) {
        return super.getCash();  
    }
    return 0.0;
}

Upvotes: 1

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