Transaction API, ReadWriteLock

12 messages

Transaction API, ReadWriteLock

Reply Threaded

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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Oliver Zeigermann

Re: Transaction API, ReadWriteLock

Reply Threaded

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, [hidden email] <[hidden email]> 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.
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: [hidden email]
> For additional commands, e-mail: [hidden email]
>
>

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LeRoy.Yanta

Re: Transaction API, ReadWriteLock

Reply Threaded

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
[hidden email]> To
Jakarta Commons Users List
07/06/2005 01:44 <[hidden email]>
AM cc

Subject
Please respond to Re: Transaction API, ReadWriteLock
"Jakarta Commons
Users List"
<commons-user@jak
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, [hidden email] <[hidden email]> 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.
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: [hidden email]
> For additional commands, e-mail: [hidden email]
>
>

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Oliver Zeigermann

Re: Transaction API, ReadWriteLock

Reply Threaded

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, [hidden email] <[hidden email]> 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
> [hidden email]> To
> Jakarta Commons Users List
> 07/06/2005 01:44 <[hidden email]>
> AM cc
>
> Subject
> Please respond to Re: Transaction API, ReadWriteLock
> "Jakarta Commons
> Users List"
> <commons-user@jak
> 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, [hidden email] <[hidden email]> 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.
> >
> >
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: [hidden email]
> > For additional commands, e-mail: [hidden email]
> >
> >
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: [hidden email]
> For additional commands, e-mail: [hidden email]
>
>
>
>
> ---------------------------------------------------------------------
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>
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Aaron Hamid

Re: Transaction API, ReadWriteLock

Reply Threaded

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, [hidden email] <[hidden email]> 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
>> [hidden email]> To
>> Jakarta Commons Users List
>> 07/06/2005 01:44 <[hidden email]>
>> AM cc
>>
>> Subject
>> Please respond to Re: Transaction API, ReadWriteLock
>> "Jakarta Commons
>> Users List"
>> <commons-user@jak
>> 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, [hidden email] <[hidden email]> 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.
>>>
>>>
>>>---------------------------------------------------------------------
>>>To unsubscribe, e-mail: [hidden email]
>>>For additional commands, e-mail: [hidden email]
>>>
>>>
>>
>>---------------------------------------------------------------------
>>To unsubscribe, e-mail: [hidden email]
>>For additional commands, e-mail: [hidden email]
>>
>>
>>
>>
>>---------------------------------------------------------------------
>>To unsubscribe, e-mail: [hidden email]
>>For additional commands, e-mail: [hidden email]
>>
>>
>
>
> ---------------------------------------------------------------------
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Oliver Zeigermann

Re: Transaction API, ReadWriteLock

Reply Threaded

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 <[hidden email]> 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, [hidden email] <[hidden email]> 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
> >> [hidden email]> To
> >> Jakarta Commons Users List
> >> 07/06/2005 01:44 <[hidden email]>
> >> AM cc
> >>
> >> Subject
> >> Please respond to Re: Transaction API, ReadWriteLock
> >> "Jakarta Commons
> >> Users List"
> >> <commons-user@jak
> >> 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, [hidden email] <[hidden email]> 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.
> >>>
> >>>
> >>>---------------------------------------------------------------------
> >>>To unsubscribe, e-mail: [hidden email]
> >>>For additional commands, e-mail: [hidden email]
> >>>
> >>>
> >>
> >>---------------------------------------------------------------------
> >>To unsubscribe, e-mail: [hidden email]
> >>For additional commands, e-mail: [hidden email]
> >>
> >>
> >>
> >>
> >>---------------------------------------------------------------------
> >>To unsubscribe, e-mail: [hidden email]
> >>For additional commands, e-mail: [hidden email]
> >>
> >>
> >
> >
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: [hidden email]
> > For additional commands, e-mail: [hidden email]
> >
>
> ---------------------------------------------------------------------
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> For additional commands, e-mail: [hidden email]
>
>

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Oliver Zeigermann

Re: Transaction API, ReadWriteLock

Reply Threaded

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 <[hidden email]> 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 <[hidden email]> 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, [hidden email] <[hidden email]> 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
> > >> [hidden email]> To
> > >> Jakarta Commons Users List
> > >> 07/06/2005 01:44 <[hidden email]>
> > >> AM cc
> > >>
> > >> Subject
> > >> Please respond to Re: Transaction API, ReadWriteLock
> > >> "Jakarta Commons
> > >> Users List"
> > >> <commons-user@jak
> > >> 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, [hidden email] <[hidden email]> 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.
> > >>>
> > >>>
> > >>>---------------------------------------------------------------------
> > >>>To unsubscribe, e-mail: [hidden email]
> > >>>For additional commands, e-mail: [hidden email]
> > >>>
> > >>>
> > >>
> > >>---------------------------------------------------------------------
> > >>To unsubscribe, e-mail: [hidden email]
> > >>For additional commands, e-mail: [hidden email]
> > >>
> > >>
> > >>
> > >>
> > >>---------------------------------------------------------------------
> > >>To unsubscribe, e-mail: [hidden email]
> > >>For additional commands, e-mail: [hidden email]
> > >>
> > >>
> > >
> > >
> > > ---------------------------------------------------------------------
> > > To unsubscribe, e-mail: [hidden email]
> > > For additional commands, e-mail: [hidden email]
> > >
> >
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: [hidden email]
> > For additional commands, e-mail: [hidden email]
> >
> >
>

---------------------------------------------------------------------
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Aaron Hamid

Re: Transaction API, ReadWriteLock

Reply Threaded

I see, so if I do not wish to manage the lock references myself, I (and LeRoy also) should always obtain locks through a LockManager.

Aaron

Oliver Zeigermann wrote:

> 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 <[hidden email]> 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 <[hidden email]> 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, [hidden email] <[hidden email]> 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
>>>>> [hidden email]> To
>>>>> Jakarta Commons Users List
>>>>> 07/06/2005 01:44 <[hidden email]>
>>>>> AM cc
>>>>>
>>>>> Subject
>>>>> Please respond to Re: Transaction API, ReadWriteLock
>>>>> "Jakarta Commons
>>>>> Users List"
>>>>> <commons-user@jak
>>>>> 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, [hidden email] <[hidden email]> 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.
>>>>>>
>>>>>>
>>>>>>---------------------------------------------------------------------
>>>>>>To unsubscribe, e-mail: [hidden email]
>>>>>>For additional commands, e-mail: [hidden email]
>>>>>>
>>>>>>
>>>>>
>>>>>---------------------------------------------------------------------
>>>>>To unsubscribe, e-mail: [hidden email]
>>>>>For additional commands, e-mail: [hidden email]
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>---------------------------------------------------------------------
>>>>>To unsubscribe, e-mail: [hidden email]
>>>>>For additional commands, e-mail: [hidden email]
>>>>>
>>>>>
>>>>
>>>>
>>>>---------------------------------------------------------------------
>>>>To unsubscribe, e-mail: [hidden email]
>>>>For additional commands, e-mail: [hidden email]
>>>>
>>>
>>>---------------------------------------------------------------------
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>>>For additional commands, e-mail: [hidden email]
>>>
>>>
>>
>
> ---------------------------------------------------------------------
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---------------------------------------------------------------------
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Oliver Zeigermann

Re: Transaction API, ReadWriteLock

Reply Threaded

Exactly. In most cases I would recommend to use a manager.

Oliver

On 7/6/05, Aaron Hamid <[hidden email]> wrote:

> I see, so if I do not wish to manage the lock references myself, I (and LeRoy also) should always obtain locks through a LockManager.
>
> Aaron
>
> Oliver Zeigermann wrote:
> > 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 <[hidden email]> 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 <[hidden email]> 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, [hidden email] <[hidden email]> 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
> >>>>> [hidden email]> To
> >>>>> Jakarta Commons Users List
> >>>>> 07/06/2005 01:44 <[hidden email]>
> >>>>> AM cc
> >>>>>
> >>>>> Subject
> >>>>> Please respond to Re: Transaction API, ReadWriteLock
> >>>>> "Jakarta Commons
> >>>>> Users List"
> >>>>> <commons-user@jak
> >>>>> 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, [hidden email] <[hidden email]> 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.
> >>>>>>
> >>>>>>
> >>>>>>---------------------------------------------------------------------
> >>>>>>To unsubscribe, e-mail: [hidden email]
> >>>>>>For additional commands, e-mail: [hidden email]
> >>>>>>
> >>>>>>
> >>>>>
> >>>>>---------------------------------------------------------------------
> >>>>>To unsubscribe, e-mail: [hidden email]
> >>>>>For additional commands, e-mail: [hidden email]
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>---------------------------------------------------------------------
> >>>>>To unsubscribe, e-mail: [hidden email]
> >>>>>For additional commands, e-mail: [hidden email]
> >>>>>
> >>>>>
> >>>>
> >>>>
> >>>>---------------------------------------------------------------------
> >>>>To unsubscribe, e-mail: [hidden email]
> >>>>For additional commands, e-mail: [hidden email]
> >>>>
> >>>
> >>>---------------------------------------------------------------------
> >>>To unsubscribe, e-mail: [hidden email]
> >>>For additional commands, e-mail: [hidden email]
> >>>
> >>>
> >>
> >
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: [hidden email]
> > For additional commands, e-mail: [hidden email]
> >
>
> ---------------------------------------------------------------------
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>

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LeRoy.Yanta

Re: Transaction API, ReadWriteLock

Reply Threaded

Switching to use a manager to manage lock references eliminates the need to
mange lock references, but doesn't this just push this reference problem to
the manager object?

If classes foo1 and foo2 needed to write to the same file, they would need
to reference the same manager object to be aware of the lock that was
created by the other class. If so, then the creation of the manager object
would need to be placed in Singleton object so both classes could obtain
the same reference to the manager object. Correct?

LeRoy

Oliver Zeigermann
<oliver.zeigerman
[hidden email]> To
Jakarta Commons Users List
07/06/2005 09:47 <[hidden email]>
AM cc

Subject
Please respond to Re: Transaction API, ReadWriteLock
"Jakarta Commons
Users List"
<commons-user@jak
arta.apache.org>

Exactly. In most cases I would recommend to use a manager.

Oliver

On 7/6/05, Aaron Hamid <[hidden email]> wrote:
> I see, so if I do not wish to manage the lock references myself, I (and
LeRoy also) should always obtain locks through a LockManager.

>
> Aaron
>
> Oliver Zeigermann wrote:
> > 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 <[hidden email]> 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 <[hidden email]> 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, [hidden email] <[hidden email]> 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
> >>>>> [hidden email]>

To
> >>>>> Jakarta Commons Users List
> >>>>> 07/06/2005 01:44
<[hidden email]>
> >>>>> AM
cc
> >>>>>
> >>>>>
Subject
> >>>>> Please respond to Re: Transaction API,
ReadWriteLock

> >>>>> "Jakarta Commons
> >>>>> Users List"
> >>>>> <commons-user@jak
> >>>>> 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, [hidden email] <[hidden email]>

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.
> >>>>>>
> >>>>>>
>
>>>>>>---------------------------------------------------------------------
> >>>>>>To unsubscribe, e-mail: [hidden email]
> >>>>>>For additional commands, e-mail:

[hidden email]
> >>>>>>
> >>>>>>
> >>>>>
>
>>>>>---------------------------------------------------------------------
> >>>>>To unsubscribe, e-mail: [hidden email]
> >>>>>For additional commands, e-mail:
[hidden email]
> >>>>>
> >>>>>
> >>>>>
> >>>>>
>
>>>>>---------------------------------------------------------------------
> >>>>>To unsubscribe, e-mail: [hidden email]
> >>>>>For additional commands, e-mail:
[hidden email]

> >>>>>
> >>>>>
> >>>>
> >>>>
> >>>>---------------------------------------------------------------------
> >>>>To unsubscribe, e-mail: [hidden email]
> >>>>For additional commands, e-mail: [hidden email]
> >>>>
> >>>
> >>>---------------------------------------------------------------------
> >>>To unsubscribe, e-mail: [hidden email]
> >>>For additional commands, e-mail: [hidden email]
> >>>
> >>>
> >>
> >
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: [hidden email]
> > For additional commands, e-mail: [hidden email]
> >
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: [hidden email]
> For additional commands, e-mail: [hidden email]
>
>

---------------------------------------------------------------------
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---------------------------------------------------------------------
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Oliver Zeigermann

Re: Transaction API, ReadWriteLock

Reply Threaded

Yes, all participating threads would need to access the same
transaction manager.

Oliver

On 7/6/05, [hidden email] <[hidden email]> wrote:

>
>
>
>
>
> Switching to use a manager to manage lock references eliminates the need to
> mange lock references, but doesn't this just push this reference problem to
> the manager object?
>
> If classes foo1 and foo2 needed to write to the same file, they would need
> to reference the same manager object to be aware of the lock that was
> created by the other class. If so, then the creation of the manager object
> would need to be placed in Singleton object so both classes could obtain
> the same reference to the manager object. Correct?
>
> LeRoy
>
>
>
>
>
>
> Oliver Zeigermann
> <oliver.zeigerman
> [hidden email]> To
> Jakarta Commons Users List
> 07/06/2005 09:47 <[hidden email]>
> AM cc
>
> Subject
> Please respond to Re: Transaction API, ReadWriteLock
> "Jakarta Commons
> Users List"
> <commons-user@jak
> arta.apache.org>
>
>
>
>
>
>
> Exactly. In most cases I would recommend to use a manager.
>
> Oliver
>
> On 7/6/05, Aaron Hamid <[hidden email]> wrote:
> > I see, so if I do not wish to manage the lock references myself, I (and
> LeRoy also) should always obtain locks through a LockManager.
> >
> > Aaron
> >
> > Oliver Zeigermann wrote:
> > > 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 <[hidden email]> 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 <[hidden email]> 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, [hidden email] <[hidden email]> 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
> > >>>>> [hidden email]>
> To
> > >>>>> Jakarta Commons Users List
> > >>>>> 07/06/2005 01:44
> <[hidden email]>
> > >>>>> AM
> cc
> > >>>>>
> > >>>>>
> Subject
> > >>>>> Please respond to Re: Transaction API,
> ReadWriteLock
> > >>>>> "Jakarta Commons
> > >>>>> Users List"
> > >>>>> <commons-user@jak
> > >>>>> 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, [hidden email] <[hidden email]>
> 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.
> > >>>>>>
> > >>>>>>
> >
> >>>>>>---------------------------------------------------------------------
> > >>>>>>To unsubscribe, e-mail: [hidden email]
> > >>>>>>For additional commands, e-mail:
> [hidden email]
> > >>>>>>
> > >>>>>>
> > >>>>>
> >
> >>>>>---------------------------------------------------------------------
> > >>>>>To unsubscribe, e-mail: [hidden email]
> > >>>>>For additional commands, e-mail:
> [hidden email]
> > >>>>>
> > >>>>>
> > >>>>>
> > >>>>>
> >
> >>>>>---------------------------------------------------------------------
> > >>>>>To unsubscribe, e-mail: [hidden email]
> > >>>>>For additional commands, e-mail:
> [hidden email]
> > >>>>>
> > >>>>>
> > >>>>
> > >>>>
> > >>>>---------------------------------------------------------------------
> > >>>>To unsubscribe, e-mail: [hidden email]
> > >>>>For additional commands, e-mail: [hidden email]
> > >>>>
> > >>>
> > >>>---------------------------------------------------------------------
> > >>>To unsubscribe, e-mail: [hidden email]
> > >>>For additional commands, e-mail: [hidden email]
> > >>>
> > >>>
> > >>
> > >
> > > ---------------------------------------------------------------------
> > > To unsubscribe, e-mail: [hidden email]
> > > For additional commands, e-mail: [hidden email]
> > >
> >
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: [hidden email]
> > For additional commands, e-mail: [hidden email]
> >
> >
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: [hidden email]
> For additional commands, e-mail: [hidden email]
>
>
>
>
> ---------------------------------------------------------------------
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> For additional commands, e-mail: [hidden email]
>
>

---------------------------------------------------------------------
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LeRoy.Yanta

Re: Transaction API, ReadWriteLock - RESOLVED

Reply Threaded

Oliver,

Thanks for your help on this issue.

LeRoy

Oliver Zeigermann
<oliver.zeigerman
[hidden email]> To
Jakarta Commons Users List
07/07/2005 02:47 <[hidden email]>
AM cc

Subject
Please respond to Re: Transaction API, ReadWriteLock
"Jakarta Commons
Users List"
<commons-user@jak
arta.apache.org>

Yes, all participating threads would need to access the same
transaction manager.

Oliver

On 7/6/05, [hidden email] <[hidden email]> wrote:
>
>
>
>
>
> Switching to use a manager to manage lock references eliminates the need
to
> mange lock references, but doesn't this just push this reference problem
to
> the manager object?
>
> If classes foo1 and foo2 needed to write to the same file, they would
need
> to reference the same manager object to be aware of the lock that was
> created by the other class. If so, then the creation of the manager
object

> would need to be placed in Singleton object so both classes could obtain
> the same reference to the manager object. Correct?
>
> LeRoy
>
>
>
>
>
>
> Oliver Zeigermann
> <oliver.zeigerman
> [hidden email]>

To
> Jakarta Commons Users List
> 07/06/2005 09:47 <[hidden email]>
> AM
cc
>
>
Subject

> Please respond to Re: Transaction API, ReadWriteLock
> "Jakarta Commons
> Users List"
> <commons-user@jak
> arta.apache.org>
>
>
>
>
>
>
> Exactly. In most cases I would recommend to use a manager.
>
> Oliver
>
> On 7/6/05, Aaron Hamid <[hidden email]> wrote:
> > I see, so if I do not wish to manage the lock references myself, I (and
> LeRoy also) should always obtain locks through a LockManager.
> >
> > Aaron
> >
> > Oliver Zeigermann wrote:
> > > 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 <[hidden email]> 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 <[hidden email]> 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, [hidden email] <[hidden email]>

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
> > >>>>> [hidden email]>
> To
> > >>>>> Jakarta Commons Users List
> > >>>>> 07/06/2005 01:44
> <[hidden email]>
> > >>>>> AM
> cc
> > >>>>>
> > >>>>>
> Subject
> > >>>>> Please respond to Re: Transaction API,
> ReadWriteLock
> > >>>>> "Jakarta Commons
> > >>>>> Users List"
> > >>>>> <commons-user@jak
> > >>>>> 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

> > >>>>>the file as String.
> > >>>>>
> > >>>>>Oliver
> > >>>>>
> > >>>>>On 7/5/05, [hidden email] <[hidden email]>
> 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.
> > >>>>>>
> > >>>>>>
> >
>
>>>>>>---------------------------------------------------------------------
> > >>>>>>To unsubscribe, e-mail:

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> > >>>>>>For additional commands, e-mail:
> [hidden email]
> > >>>>>>
> > >>>>>>
> > >>>>>
> >
>
>>>>>---------------------------------------------------------------------
> > >>>>>To unsubscribe, e-mail:
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> > >>>>>For additional commands, e-mail:
> [hidden email]
> > >>>>>
> > >>>>>
> > >>>>>
> > >>>>>
> >
>
>>>>>---------------------------------------------------------------------
> > >>>>>To unsubscribe, e-mail:

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> > >>>>>For additional commands, e-mail:
> [hidden email]
> > >>>>>
> > >>>>>
> > >>>>
> > >>>>
> >
>>>>---------------------------------------------------------------------
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> > >>>>For additional commands, e-mail:

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> > >>>>
> > >>>
> >
>>>---------------------------------------------------------------------
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> > >>>
> > >>>
> > >>
> > >
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> > >
> >
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