Is this an example of Composition?

Question

The following code is given:

class Warren
{
  private const int MaxRabbitsInWarren = 99;
  private Rabbit[] Rabbits;
  private int RabbitCount = 0;
  private int PeriodsRun = 0;
  private bool AlreadySpread = false;
  private int Variability;
  private static Random Rnd = new Random();

  public Warren(int Variability)
  {
    this.Variability = Variability;
    Rabbits = new Rabbit[MaxRabbitsInWarren];
    RabbitCount = (int)(CalculateRandomValue((int)(MaxRabbitsInWarren / 4), this.Variability));
    for (int r = 0; r < RabbitCount; r++)
    {
      Rabbits[r] = new Rabbit(Variability);
    }
  }
}

• There is an array called Rabbits, of type Rabbit, which is a field of class Warren.
• The Warren constructor creates a random number of ‘Rabbits’ to be placed in the Rabbits array.

Because the array Rabbits is a member of the Warren class, does this means that its lifecycle is tightly bound to the Warren class? (ie. destroying a warren, destroys the rabbit array?)

Answer 1

Is this an example of composition?

Yes - a Warren "has an" array of Rabbits.

does this means that [the array of Rabbits'] lifecycle is tightly bound to the Warren class?

Not necessarily. The specifics may vary between languages (I'm assuming that your language has some kind of automatic garbage collection), but if the array is shared outside of the Warren instance (and a reference to it is kept) it would survive even after the Warren is destroyed.