On Tue, Jul 7, 2020 at 7:14 PM Matt Sicker <boa...@gmail.com> wrote: > JCIP seems to call this idea a monitor, but that’s also the general > implicit locking mechanism in Java. >
Hi Matt, Right, and it is tempting to rename LockingVisitors.AbstractLockVisitor's 'object' ivar to 'monitor' but that is somewhat misleading because it is not that object that you are locking, instead you are locking an actual lock and then visiting that object. So I am inclined to keep that part but Monitor could be in the class name somewhere. Gary > On Tue, Jul 7, 2020 at 17:56 Gary Gregory <garydgreg...@gmail.com> wrote: > > > Typo: LockingVisitors. > > > > On Tue, Jul 7, 2020 at 6:56 PM Gary Gregory <garydgreg...@gmail.com> > > wrote: > > > > > In the PR https://github.com/apache/commons-lang/pull/559 I am going > > > with "LockingVistors". > > > > > > Gary > > > > > > On Tue, Jul 7, 2020 at 2:33 PM Rob Tompkins <chtom...@gmail.com> > wrote: > > > > > >> I’m not all that familiar with that area of academia. Let me see what > I > > >> can dig up > > >> > > >> -Rob > > >> > > >> > On Jul 7, 2020, at 2:19 PM, Matt Sicker <boa...@gmail.com> wrote: > > >> > > > >> > Are there any academic references for this? Or even something from > > >> > Java Concurrency in Practice? Those are good sources for names > around > > >> > concurrency. > > >> > > > >> > On Tue, 7 Jul 2020 at 12:42, Rob Tompkins <chtom...@gmail.com> > wrote: > > >> >> > > >> >> Why not make the name “ThreadedLambdaSynchronizer” or something > like > > >> that….just something more descriptive here that get’s closer to what > the > > >> intended functionality is. > > >> >> > > >> >> That said, I’m not particularly tied to the name > > >> “ThreadedLambdaSynchronizer” just spitballing here for something more > > >> descriptive than “Lock” > > >> >> > > >> >> -Rob > > >> >> > > >> >>> On Jun 29, 2020, at 12:58 PM, Matt Sicker <boa...@gmail.com> > wrote: > > >> >>> > > >> >>> Now that starts to sound like Apache Groovy or Kotlin. > > >> >>> > > >> >>> On Mon, 29 Jun 2020 at 11:58, Xeno Amess <xenoam...@gmail.com> > > wrote: > > >> >>>> > > >> >>>> soemtimes I really wish to rewrite/add some functions in jdk > > >> directly... > > >> >>>> especially for reusing some package private static functions... > > >> >>>> > > >> >>>> Gary Gregory <garydgreg...@gmail.com> 于2020年6月30日周二 上午12:01写道： > > >> >>>> > > >> >>>>> I'm not sure talking to the JDK folks is helpful IMO. We are > still > > >> >>>>> targeting Java 8. The customers I deal with are migrating from 8 > > to > > >> 11, and > > >> >>>>> Java 11 is not everywhere our customers are. So talking about > > >> something > > >> >>>>> that might end up in Java... 25 seems to be not in our user's > best > > >> or > > >> >>>>> immediate interest. It might be good for Java in the long oh so > > >> long term > > >> >>>>> of course. > > >> >>>>> > > >> >>>>> Gary > > >> >>>>> > > >> >>>>> On Mon, Jun 29, 2020 at 8:31 AM Rob Tompkins < > chtom...@gmail.com> > > >> wrote: > > >> >>>>> > > >> >>>>>> At first look, I’m a little surprised we’re trying to take on > > this > > >> >>>>>> functionality. Has anyone reached out to the JDK guys to see if > > >> they’d be > > >> >>>>>> interested in having it in the JDK? That said, if we approach > it > > >> from > > >> >>>>> that > > >> >>>>>> path, we would lose the functionality in older versions of > java. > > So > > >> >>>>> maybe I > > >> >>>>>> just talked myself out of the idea of putting it in the JDK.... > > >> >>>>>> > > >> >>>>>> Just wanted to stream of consciousness my initial gut vibe. > > >> >>>>>> > > >> >>>>>> Cheers, > > >> >>>>>> -Rob > > >> >>>>>> > > >> >>>>>>> On Jun 26, 2020, at 10:07 AM, Gary Gregory < > > >> garydgreg...@gmail.com> > > >> >>>>>> wrote: > > >> >>>>>>> > > >> >>>>>>> Hi All: > > >> >>>>>>> > > >> >>>>>>> I know email is a challenging medium for code reviews, so > please > > >> >>>>> consider > > >> >>>>>>> these comments coming from my best intentions, constructive > and > > >> caring > > >> >>>>>> ;-) > > >> >>>>>>> Also please excuse the meandering nature of this post. > > >> >>>>>>> > > >> >>>>>>> The new class org.apache.commons.lang3.concurrent.Locks.Lock > > needs > > >> >>>>> better > > >> >>>>>>> names IMO, not just the class name. There is already a JRE > > >> interface > > >> >>>>>> called > > >> >>>>>>> Lock so this class name is confusing (to me.) > > >> >>>>>>> > > >> >>>>>>> The Javadoc reads in part: > > >> >>>>>>> > > >> >>>>>>> * This class implements a wrapper for a locked (hidden) > > object, > > >> and > > >> >>>>>>> * provides the means to access it. The basic idea, is that > the > > >> user > > >> >>>>>>> * code forsakes all references to the locked object, using > > only > > >> the > > >> >>>>>>> * wrapper object, and the accessor methods > > >> >>>>>>> > > >> >>>>>>> But this is not the case, the object itself is not locked in > > >> >>>>>>> the traditional sense with a monitor through a synchronized > > >> block, so > > >> >>>>> we > > >> >>>>>>> need to update the Javadoc as well. > > >> >>>>>>> > > >> >>>>>>> To me, this is more about executing blocks of code (through > > >> lambdas) > > >> >>>>>> which > > >> >>>>>>> then get 'safe' (via locking) access to an underlying object. > > This > > >> >>>>> tells > > >> >>>>>> me > > >> >>>>>>> the class is more about the functional interfaces than about a > > >> domain > > >> >>>>>>> "Object", hence the name "Lock" is not the best. It's really > > more > > >> of a > > >> >>>>>>> visitor where the visitation pattern is: Lock, Visit, Unlock. > > >> >>>>>>> Instead, maybe: > > >> >>>>>>> - StampledLockVisitor (more specific) > > >> >>>>>>> - LockingVisitor (more general) > > >> >>>>>>> - SafeObject (vague) > > >> >>>>>>> - ObjectLocker (vague) > > >> >>>>>>> - rejected: LockedObject since the object itself is not > locked. > > >> >>>>>>> - ? > > >> >>>>>>> > > >> >>>>>>> What is also confusing IMO is that the instance variable for > the > > >> object > > >> >>>>>> is > > >> >>>>>>> called "lockedObject" but the object is in fact NOT locked all > > the > > >> >>>>> time. > > >> >>>>>> So > > >> >>>>>>> that needs to be renamed IMO: > > >> >>>>>>> - object (the simplest) > > >> >>>>>>> - subject > > >> >>>>>>> - domain > > >> >>>>>>> - target > > >> >>>>>>> - ? > > >> >>>>>>> > > >> >>>>>>> In the same vein, the StampedLock is named "lock" which is > also > > >> >>>>> confusing > > >> >>>>>>> since StampedLock does not implement Lock. > > >> >>>>>>> > > >> >>>>>>> Why can't the domain object be null, it's never used by the > > >> framework? > > >> >>>>>>> Why this: > > >> >>>>>>> if (t == lockedObject) { > > >> >>>>>>> throw new IllegalStateException("The returned > > >> object > > >> >>>>>>> is, in fact, the hidden object."); > > >> >>>>>>> } > > >> >>>>>>> ? > > >> >>>>>>> This seems like an application specific constraint that has > > >> nothing to > > >> >>>>> do > > >> >>>>>>> with the framework. > > >> >>>>>>> > > >> >>>>>>> Now that I've considered the above, the API Locks.lock(O) is > > >> really > > >> >>>>>>> misnamed, because it does not lock anything, it's a factory > > >> method. > > >> >>>>>>> > > >> >>>>>>> Stepping back even more, since there is only a static inner > > class > > >> in > > >> >>>>>> Locks, > > >> >>>>>>> and no-hint that alternative implementations for different > kind > > of > > >> >>>>> locks > > >> >>>>>>> are possible, I would say we do not need Locks, all we need is > > >> what is > > >> >>>>>> now > > >> >>>>>>> called Lock. > > >> >>>>>>> > > >> >>>>>>> It's not clear why some methods are protected, I would make > > those > > >> >>>>>> private. > > >> >>>>>>> It's not like I can use or plugin a Lock, > > ReentrantReadWriteLock, > > >> a > > >> >>>>>>> ReentrantLock, or any ReadWriteLock instead of a StampedLock. > I > > >> would > > >> >>>>>> then > > >> >>>>>>> make the current Lock class a standalone class which can then > be > > >> used > > >> >>>>>> later > > >> >>>>>>> from a factory class (now Locks) where we can then fill in > with > > >> >>>>> different > > >> >>>>>>> implementations. > > >> >>>>>>> > > >> >>>>>>> The Javadoc talks about a "hidden" object but it is not hidden > > >> since it > > >> >>>>>> is > > >> >>>>>>> passed to all visitors! > > >> >>>>>>> > > >> >>>>>>> This test assumption is wrong: > > >> >>>>>>> > > >> >>>>>>> If our threads are running concurrently, then we expect > to > > >> be > > >> >>>>>>> faster > > >> >>>>>>> than running one after the other. > > >> >>>>>>> > > >> >>>>>>> The VM or Java spec makes no such guarantee and the tests have > > no > > >> >>>>> control > > >> >>>>>>> over VM scheduling. There are cases where this will fail when > > >> under > > >> >>>>> heavy > > >> >>>>>>> load for example where the cost of additional threads becomes > > >> >>>>>> overwhelming. > > >> >>>>>>> > > >> >>>>>>> Another item I am quite doubtful about is hiding checked > > >> exceptions by > > >> >>>>>>> rethrowning them as unchecked. I'd consider this an > > anti-pattern. > > >> If I > > >> >>>>> am > > >> >>>>>>> using one of our "Failing" interfaces it is because I am > > >> expecting it > > >> >>>>> to > > >> >>>>>>> fail. Perhaps this could be made smoother by refactoring to > pass > > >> in a > > >> >>>>>>> lambda for an exception handler. > > >> >>>>>>> > > >> >>>>>>> I've crystallized my thoughts into code here as WIP (Javadoc > > needs > > >> >>>>> work): > > >> >>>>>>> https://github.com/apache/commons-lang/pull/559 > > >> >>>>>>> > > >> >>>>>>> Not as important as the above: > > >> >>>>>>> The example in the Javadoc uses logging as its domain > subject, a > > >> >>>>>> "logging" > > >> >>>>>>> API (PrintStream) which is not a good example IMO. Logging > > >> frameworks > > >> >>>>>>> today like Log4j handle multi-threaded applications normally > > >> without > > >> >>>>>> having > > >> >>>>>>> developers meddle in it. Yes, I understand it's a simple > example > > >> but I > > >> >>>>> am > > >> >>>>>>> hoping we can come up with something more realistic or useful. > > >> >>>>>>> > > >> >>>>>>> Thank you, > > >> >>>>>>> Gary > > >> >>>>>> > > >> >>>>>> > > >> --------------------------------------------------------------------- > > >> >>>>>> To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org > > >> >>>>>> For additional commands, e-mail: dev-h...@commons.apache.org > > >> >>>>>> > > >> >>>>>> > > >> >>>>> > > >> >>> > > >> >>> > > >> >>> > > >> >>> -- > > >> >>> Matt Sicker <boa...@gmail.com> > > >> >>> > > >> >>> > > --------------------------------------------------------------------- > > >> >>> To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org > > >> >>> For additional commands, e-mail: dev-h...@commons.apache.org > > >> >>> > > >> >> > > >> >> > > >> >> > --------------------------------------------------------------------- > > >> >> To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org > > >> >> For additional commands, e-mail: dev-h...@commons.apache.org > > >> >> > > >> > > > >> > > > >> > -- > > >> > Matt Sicker <boa...@gmail.com> > > >> > > > >> > > --------------------------------------------------------------------- > > >> > To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org > > >> > For additional commands, e-mail: dev-h...@commons.apache.org > > >> > > > >> > > >> > > >> --------------------------------------------------------------------- > > >> To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org > > >> For additional commands, e-mail: dev-h...@commons.apache.org > > >> > > >> > > > -- > Matt Sicker <boa...@gmail.com> >
