RFR 8024253: ThreadLocal random can use SecureRandom for the initial seed

[Paul Sandoz]

[Catching up after J1]

On Sep 24, 2013, at 9:16 AM, Martin Buchholz <martinrb at google.com> wrote:

> Stupid SplittableRandom tricks:
> 
>            System.out.println(sr.nextDouble(0.0d,
> Double.POSITIVE_INFINITY));
> always prints constant 1.7976931348623157E308
> 
> which might be considered a bug.
> 

Right, Double.MAX_VALUE.

We thought not worth the effort of exhaustively supporting all possible IllegalArgumentException cases:

  nextDouble(+oo) => Double.MAX_VALUE
  nextDouble(-oo, finite) => NaN
  nextDouble(-oo, +oo) => NaN
  nextDouble(finite, +oo) => Double.MAX_VALUE


> ---
> 
> The spec below fails to be pedantically correct when one of the args is NaN.
> 
> * @throws IllegalArgumentException if {@code origin} is greater than
>     *         or equal to {@code bound}
>     */
>    public double nextDouble(double origin, double bound) {
> 
> Better to draw inspiration from the spec for
>     * @throws IllegalArgumentException if {@code bound} is not positive
>     */
>    public double nextDouble(double bound) {
> 
> and write:
> 
>     * @throws IllegalArgumentException if {@code bound - origin} is not
> positive
>     */
>    public double nextDouble(double origin, double bound) {
> 

That would be a good change to tack on to that for the better reporting of incorrect bounds.

Paul.