8005697: Add StampedLock - JEP 155

[Doug Lea]

On 01/28/13 06:32, Chris Hegarty wrote:
> As part of JEP 155 (Concurrency Updates) we are proposing to add StampedLock. A
> capability-based lock with three modes for controlling read/write access.
>
> Javadoc:
>
> http://cr.openjdk.java.net/~chegar/8005697/ver.00/javadoc/StampedLock.html
>   (some external links are not working in this online version)
>
> Webrev:
>    http://cr.openjdk.java.net/~chegar/8005697/ver.00/webrev/webrev/
>

Martin Buchholz pointed out a javadoc warning.
I also noticed that I had failed to include the simple
toString-based informal debug/monitoring aids that we've
been doing for synchronizers. Sorry. Now added.
For example, printing a lock twice during a test:
java.util.concurrent.locks.StampedLock at 29178281[Read-locks:13]
...
java.util.concurrent.locks.StampedLock at 29178281[Unlocked]

-Doug