Abstract Class return

[Robben]

Suppose I have an abstract class named Animal (there are many other animal types that are made as classes). In this abstract class it has two methods, reproduction(Animal otherAnimal) and reproducing(Animal otherAnimal). Reproduction determines if the animal can reproduce with another instance of an animal. Reproducing should return a new Animal of the same type if reproduction is possible, but I do not know how to do this because the class is abstract.

public abstract class Animal{
    public abstract boolean reproduction(Animal otherAnimal);
   
    public Animal reproducing(Animal otherAnimal) {
        if (reproduction(otherAnimal) == true) {
            return ... //how can I return a new Animal of the same type?   
        }
        else {
            return null;       
        }
    }
}

[JosAH]

Why don't you let the (concrete subclass of) Animal reproduce itself? It should test the otherAnimal and reproduce if it is a compatible animal. The 'instanceof' operator can come in handy here, e.g.

public class Aardvark extends Animal {
   ...
   public Animal reproduce(Animal otherAnimal) {
      if (otherAnimal instanceof Aardvark)
        return new Aardvark();
      return null;
   }
   ...
}

Of course the reproduce( ... ) method is abstract again in the Animal class itself.

kind regards,

Jos

[DarrylBurke]

        if (reproduction(otherAnimal) == true) {

Why stop at one?

        if ((((reproduction(otherAnimal) == true) == true) == true) == true) {

More seriously, never compare a boolean expression with a boolean literal. It's unnecessary, adds avoidable clutter, and when comparing a variable with a literal, is error prone.

        if (reproduction(otherAnimal)) {

Also, you might want to rethink your method names. I would name your reproduction(..) method canReproduce(...) or canReproduceWith(...).

db

[JosAH]

I feel a naughty orgy description coming up ...

kindest regards,

Jos

[DarrylBurke]

I feel a naughty orgy description coming up ...

kindest regards,

Jos

class Jos extends Animal {

  public boolean reproduction(Animal otherAnimal) {
    return true;
  }
}

db

[Robben]

Why don't you let the (concrete subclass of) Animal reproduce itself? It should test the otherAnimal and reproduce if it is a compatible animal. The 'instanceof' operator can come in handy here, e.g.

public class Aardvark extends Animal {
   ...
   public Animal reproduce(Animal otherAnimal) {
      if (otherAnimal instanceof Aardvark)
        return new Aardvark();
      return null;
   }
   ...
}

Of course the reproduce( ... ) method is abstract again in the Animal class itself.

kind regards,

Jos

Hmm, I see so I should instead make my current reproducing method abstract and when I build my subclass of Animal then I will use your method using instanceof? Thank you!

Why stop at one?

        if ((((reproduction(otherAnimal) == true) == true) == true) == true) {

More seriously, never compare a boolean expression with a boolean literal. It's unnecessary, adds avoidable clutter, and when comparing a variable with a literal, is error prone.

        if (reproduction(otherAnimal)) {

Also, you might want to rethink your method names. I would name your reproduction(..) method canReproduce(...) or canReproduceWith(...).

db

Oh wow, thank you for catching that! How will I go about making the necessary change in order to avoid infinitely reproducing?

I feel a naughty orgy description coming up ...

kindest regards,

Jos

Lmao!