BowlingBall, inner class

letsbowl0.1.groovy

interface IBowlingBall {
    String getPetName();
}

class Bowler {
    static private class BowlingBall implements IBowlingBall{
        private String petName;

        BowlingBall() {
        }

        private void setPetName(String petName) {
            this.petName = petName;
        }

        String getPetName() {
            return this.petName;
        }
    }

    private BowlingBall bowlingBall;

    Bowler() {
            this.bowlingBall = new BowlingBall();
    }

    void setPetName(String petName) {
        if (petName ==~ /[A-Z][a-z\s]*/) {
            bowlingBall.setPetName(petName);
        } else {
            throw Exception("only letters, please")
        }
    }

    String getPetName() {
        return bowlingBall.getPetName();
    }
}


// test
Bowler bowler = new Bowler();

bowler.setPetName("Gutter Duster");

print bowler.getPetName()

bowler.setPetName("Pentium 386");   // exception thrown