By the way, when giving me first advice I stumbled over exactly this
difference between the lock manager and the lock itself...
Oliver
On 7/6/05, Oliver Zeigermann <[EMAIL PROTECTED]> wrote:
> You are right, but only for the lock manager. The lock manager takes
> care of uniquely mapping a resource id to a lock, but when you work on
> a lock *directly* it must - of course - be the same object.
>
> Oliver
>
> On 7/6/05, Aaron Hamid <[EMAIL PROTECTED]> wrote:
> > Is this true? It was my impression, have first written such a class, and
> > then finding and skimming the javadoc for [ReadWrite]LockManager, and
> > particularly 'getLock' and 'createLock', that lock singletons would be
> > automatically created and managed. Otherwise the developer must write a
> > lot of boilerplate code for keeping a singleton map of locks. Surely only
> > the 'resourceId' must be the same, and not the actual ReadWriteLock
> > reference?
> >
> > LockManager: "Encapsulates creation, removal, and retrieval of locks. Each
> > resource can have at most a single lock."
> >
> > Aaron
> >
> > Oliver Zeigermann wrote:
> > > Ooops, sorry, you are right. Not only the resource Id, but the lock
> > > *itself* must be the same in both threads.
> > >
> > > Doing it this way:
> > >
> > > final ReadWriteLock fileLock = new ReadWriteLock("Huhu",
> > > loggerFacade);
> > > Runnable run = new Runnable() {
> > >
> > > public void run() {
> > >
> > > try {
> > > System.out.println("before
> > > acquiring a lock "
> > > +
> > > Thread.currentThread());
> > > boolean result =
> > > fileLock.acquireWrite(Thread
> > > .currentThread(),
> > > Long.MAX_VALUE);
> > > System.out.println("lock result: "
> > > + result + " "
> > > +
> > > Thread.currentThread());
> > > Thread.sleep(20000);
> > > System.out.println("after sleeping "
> > > +
> > > Thread.currentThread());
> > > } catch (InterruptedException e) {
> > > e.printStackTrace(System.err);
> > >
> > > } finally {
> > >
> > > fileLock.release(Thread.currentThread());
> > > }
> > > }
> > >
> > > };
> > >
> > > Thread t1 = new Thread(run, "Thread1");
> > > Thread t2 = new Thread(run, "Thread2");
> > > t1.start();
> > > try {
> > > Thread.sleep(1000);
> > > } catch (InterruptedException e) {
> > > }
> > > t2.start();
> > >
> > >
> > > works fine for me.
> > >
> > > HTH
> > >
> > > Oliver
> > >
> > > On 7/6/05, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
> > >
> > >>
> > >>
> > >>
> > >>
> > >>Oliver,
> > >>
> > >>I tried your suggestion by changing my ReadWriteLock statement to
> > >>
> > >>ReadWriteLock fileLock = new ReadWriteLock("c:/logRec.txt",loggerFacade);
> > >>
> > >>However, I received the same results as when I used new File(..).
> > >>
> > >>LeRoy
> > >>
> > >>
> > >>
> > >>
> > >>
> > >>
> > >> Oliver Zeigermann
> > >> <oliver.zeigerman
> > >> [EMAIL PROTECTED]>
> > >> To
> > >> Jakarta Commons Users List
> > >> 07/06/2005 01:44 <[email protected]>
> > >> AM cc
> > >>
> > >> Subject
> > >> Please respond to Re: Transaction API, ReadWriteLock
> > >> "Jakarta Commons
> > >> Users List"
> > >> <[EMAIL PROTECTED]
> > >> arta.apache.org>
> > >>
> > >>
> > >>
> > >>
> > >>
> > >>
> > >>Most likely your problem ist that new File(..) creates different
> > >>objects in each thread. I would try using something like the path to
> > >>the file as String.
> > >>
> > >>Oliver
> > >>
> > >>On 7/5/05, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
> > >>
> > >>>
> > >>>
> > >>>
> > >>>I'm trying to use the ReadWriteLock class to acquire a write lock on a
> > >>
> > >>file
> > >>
> > >>>in a servlet. When I generate multiple threads of the servlet using a
> > >>
> > >>WTE
> > >>
> > >>>5.1 server in the WSAD 5.1 IDE, I'm not able to get ReadWriteLock to
> > >>
> > >>block
> > >>
> > >>>other servlet threads after the first servlet thread obtains the lock.
> > >>
> > >>I'm
> > >>
> > >>>using two IE browser windows to generate the two servlet threads. Below
> > >>
> > >>is
> > >>
> > >>>ReadWriteLock code I have in the servlet followed by the
> > >>
> > >>System.out.println
> > >>
> > >>>statements that are generated in the server log file during my test.
> > >>>
> > >>>ReadWriteLock fileLock = new ReadWriteLock(new File(c:/logRec.txt,
> > >>>loggerFacade);
> > >>>try {
> > >>> System.out.println("before acquiring a lock " +
> > >>>Thread.currentThread());
> > >>> boolean result =
> > >>>fileLock.acquireWrite(Thread.currentThread(),Long.MAX_VALUE);
> > >>> System.out.println("lock result: " + result + " " +
> > >>>Thread.currentThread());
> > >>> Thread.sleep(20000);
> > >>> System.out.println("after sleeping " + Thread.currentThread());
> > >>> FileWriter recFile = new FileWriter(c:/logRec.txt, true);
> > >>> recFile.write("text from testFileTran");
> > >>> recFile.close();
> > >>>} catch (InterruptedException e) {
> > >>> e.printStackTrace(System.err);
> > >>>
> > >>>} catch (IOException e) {
> > >>> e.printStackTrace(System.err);
> > >>>
> > >>>} finally {
> > >>> fileLock.release(Thread.currentThread());
> > >>>}
> > >>>
> > >>>[7/5/05 8:26:03:326 CDT] 7c1477e SystemOut O before acquiring a lock
> > >>>Thread[Servlet.Engine.Transports : 0,5,main]
> > >>>[7/5/05 8:26:03:326 CDT] 7c1477e SystemOut O lock result: true
> > >>>Thread[Servlet.Engine.Transports : 0,5,main]
> > >>>[7/5/05 8:26:08:384 CDT] 24c3477d SystemOut O before acquiring a lock
> > >>>Thread[Servlet.Engine.Transports : 1,5,main]
> > >>>[7/5/05 8:26:08:384 CDT] 24c3477d SystemOut O lock result: true
> > >>>Thread[Servlet.Engine.Transports : 1,5,main]
> > >>>[7/5/05 8:26:23:335 CDT] 7c1477e SystemOut O after sleeping
> > >>>Thread[Servlet.Engine.Transports : 0,5,main]
> > >>>[7/5/05 8:26:28:382 CDT] 24c3477d SystemOut O after sleeping
> > >>>Thread[Servlet.Engine.Transports : 1,5,main]
> > >>>
> > >>>
> > >>>From reviewing the Transaction documentation and mailing list archives,
> > >>
> > >>I'm
> > >>
> > >>>not able to determine what I'm doing wrong.
> > >>>
> > >>>
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