double getValueForPeriod (int periodNumber) {
try {
return _values[periodNumber];
} catch (ArrayIndexOutOfBoundsException e) {
return 0;
}
}

double getValueForPeriod (int periodNumber) {
if (periodNumber >= _values.length) return 0;
return _values[periodNumber];
}
For more information see page 315 of Refactoring