public void choose()
    {
        final int NUM_RANGE = 3;
        int choiceNum = (int) (NUM_RANGE * Math.random());
        if (choiceNum == 0)
        {
            this.choice = "rock";
        }
        else if (choiceNum == 1)
        {
            this.choice = "paper";
        }
        else 
        {
            this.choice = "scissors";
        }
    }