RFR 7004967: SecureRandom should be more explicit about threading

[Wang Weijun]

Please review the updated webrev at

    http://cr.openjdk.java.net/~weijun/7004967/webrev.02/

Only spec change [1].

This change also covers 8169312.

Thanks
Max

[1] 
http://cr.openjdk.java.net/~weijun/7004967/webrev.02/interdiff.patch.html

On 11/4/2016 10:54 PM, Sean Mullan wrote:
> * SecureRandom
>
>  131  * If this attribute is not set or is "false", this class will instead
>  132  * synchronize access to each of the methods of the {@code
> SecureRandomSpi}
>  133  * implementation.
>
> Not all of the methods are synchronized - engineGetParameters is not,
> for example. I think to avoid ambiguity, you should list the names of
> the methods that are synchronized.
>
> 810      * @throws IllegalArgumentException if {@code numBytes} is negative
>
> Since this is a new @throws, you really need to file a new bug.
>
> Please also file a docs bug with a description of the new attribute.
>
> * SecureRandomSpi
>
> lines 63-83, I think the wording could be improved/simplified, how about:
>
> See {@link SecureRandom} for additional details on thread safety. By
> default, a SecureRandomSpi implementation is considered to be not safe
> for use by multiple concurrent threads and SecureRandom will synchronize
> access to each of the applicable engine methods (see SecureRandom for
> the list of methods). However, if a SecureRandomSpi implementation is
> thread-safe, the <a
> href="{@docRoot}/../technotes/guides/security/StandardNames.html#Service">service
> provider attribute</a> "ThreadSafe" should be set to "true" during its
> registration, as follows:
>
>   put("SecureRandom.AlgName ThreadSafe", "true");
>
>   or
>
>   putService(new Service(this, "SecureRandom", "AlgName", className,
>              null, Map.of("ThreadSafe", "true")));
>
> {@code SecureRandom} will then call the applicable engine methods
> without any synchronization.
>
> --Sean
>
> On 11/2/16 3:27 AM, Wang Weijun wrote:
>> Ping again.
>>
>> There is an updated version at
>> http://cr.openjdk.java.net/~weijun/7004967/webrev.01/ with doc-only
>> changes.
>>
>> Thanks
>> Max
>>
>>> On Aug 25, 2016, at 10:00 AM, Weijun Wang <weijun.wang at oracle.com>
>>> wrote:
>>>
>>> Please review the enhancement at
>>>
>>>  http://cr.openjdk.java.net/~weijun/7004967/webrev.00/
>>>
>>> Basically, we want SecureRandom to be more efficient by removing all
>>> synchronized keywords from its public methods and let an
>>> implementation to take care of thread-safety (We already did some in
>>> JDK-8098581). On the other hand, we need to make sure that existing
>>> implementations that have not synchronized correctly to behave just
>>> as good as before.
>>>
>>> Therefore a new Service Attribute "ThreadSafe" is introduced. If you
>>> think your implementation is already thread-safe, set it to "true"
>>> and SecureRandom will be happy. Otherwise, don't set it and
>>> SecureRandom will continuously call your SecureRandomSpi engine
>>> methods in synchronized blocks.
>>>
>>> Thanks
>>> Max
>>