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https://jira.jboss.org/jira/browse/JBTM-503?page=com.atlassian.jira.plugi...
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Andrew Dinn commented on JBTM-503:
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The comment 'TODO why?' is probably because the shutdown code has not yet been
tested. It is clear that this routine needs to be called by the RecoveryManagerImple and
not by your code -- the RecoveryManager implementation should clean up its own detritus.
However, after a cursory eyeball of the code I believe the current version of
ExpiredEntryMonitor needs to be supplemented with some synchronization. It should ensure
that the shutdown call does not clear _started and return before the thread held in
_theInstance has exited. If it does and then startup() is called it will be possible for
the old thread to start processing a new scanner list. Synchronization issues aside, it is
probably bad form for RecoveryManagerImple to return from stop when it has not really
stopped a thread which it started.
If you need to get this to work just now then I suggest you either
i) implement and test a version of shutdown which performs the required synchronization,
call it from RecoveryManagerimple.stop(), then send us your patch for inclusion in a
future release (we are very glad to accept contributions from those who know what they are
doing).
or
ii) bodge it as you indicated above and wait for us to release a tested version
Shutdown the ExpiredEntryMonitor when stopping the RecoveryManager
------------------------------------------------------------------
Key: JBTM-503
URL:
https://jira.jboss.org/jira/browse/JBTM-503
Project: JBoss Transaction Manager
Issue Type: Feature Request
Security Level: Public(Everyone can see)
Components: Recovery
Affects Versions: 4.5
Environment: Tomcat + Spring + DBCP + JBossJTA
Reporter: Mauro Molinari
When the recovery manager is started, the implementation RecoveryManagerImple starts the
ExpiredEntryMonitor.
When you stop the recovery manager, however, the ExpiredEntryMonitor is not shut down.
On line 250 of com.arjuna.ats.internal.arjuna.recovery.RecoveryManagerImple there's
the line ExpiredEntryMonitor.shutdown() commented out, with a "TODO why?"
comment immediately before.
I don't know exactly what should be the lifecylce of ExpiredEntryMonitor versus that
of RecoveryManagerImple, however I think that one of the following should happen:
- ExpiredEntryMonitor is started when RecoveryManagerImple is started (rather than
constructed), so that it is shut down when the RecoveryManagerImple is stopped
OTHERWISE
- RecoveryManagerImple provides a way to "dispose" or "disable" it
and this includes the shutdown of ExpiredEntryMonitor
OTHERWISE
- it is documented that stopping the recovery manager needs the ExpiredEntryMonitor to be
stopped too: however, please consider that
com.arjuna.ats.internal.arjuna.recovery.ExpiredEntryMonitor.shutdown() throws a
NullPointerException if called while the ExpiredEntryMonitor has not been started before
and there is no public method to test if it has been started or not; so if I need to write
some code that stops the ExpiredEntryMonitor (without knowing if it has been started or
not) I have to write some ugly code like:
{code:java}
try
{
ExpiredEntryMonitor.shutdown();
}
catch(final NullPointerException e)
{
// ExpiredEntryMonitor had not been started
}
{code}
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