Would something like that help. That's probably something what David meant.
@Singleton
@Startup
@Lock(LockType.READ)
@ConcurrencyManagement(ConcurrencyManagementType.CONTAINER)
public class UniversalConfigurationService {
@Inject
UniversalConfigurationDao configDao;
private ConcurrentHashMap<Integer, ConcurrentHashMap<Integer,
ConfigValue>> configCache = new ConcurrentHashMap<>();
@PostConstruct
@Lock(LockType.WRITE) //probably not nedded right?
public void init() {
this.configCache = configDao.getAllConfigurations();
}
}
2015-03-09 19:10 GMT+01:00 Matej <[email protected]>:
> I added a short stacktrace. Will try to provide better one. Somehow is
> seems, like the system is not fully initialized, like some injection
> missing.. Without the (configurationService.getBoolean, everything loads
> normally. Is the MDB system initialized before EJBs?
>
>
> Here is the Singleton snippet:
> @Singleton
> @Startup
> @ConcurrencyManagement(ConcurrencyManagementType.BEAN)
> public class UniversalConfigurationService {
>
> @Inject
> UniversalConfigurationDao configDao;
>
> private ConcurrentHashMap<Integer, ConcurrentHashMap<Integer,
> ConfigValue>> configCache = new ConcurrentHashMap<>();
>
> @PostConstruct
> public void init() {
> this.configCache = configDao.getAllConfigurations();
> }
> }
>
> and here te MDB
>
> MessageDriven(activationConfig = {
> @ActivationConfigProperty(propertyName = "destinationType",
> propertyValue = "javax.jms.Queue"),
> @ActivationConfigProperty(propertyName = "destination", propertyValue
> = "EtaStatisticalRes")})
> @DependsOn("UniversalConfigurationService")
> public class EtaStatisticalResHandler implements MessageListener {
>
> @Inject
> public Logger logger;
>
> @Inject
> UniversalConfigurationService configurationService;
>
> @Override
> public void onMessage(Message message) {
>
> if (configurationService.getBoolean(ETA.getCode(),
> EMBEDDED_ETA_REPORTING.getCode())) {
> return;
> }
> }
>
>
>
>
>
> 2015-03-08 5:31 GMT+01:00 David Blevins <[email protected]>:
>
>> The @DependsOn annotation only works for other @Singleton beans.
>>
>> Definitely use CONTAINER concurrency. Understand that this code is just
>> a plain jvm ReentrantReadWriteLock under the covers. It would be hard to
>> do much better.
>>
>> -
>> http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/locks/ReentrantReadWriteLock.html
>>
>> All methods annotated with an @Lock(READ) acquire a read lock. All
>> methods annotated with @Lock(WRITE) acquire a write lock.
>>
>> That said, if you're already doing the configuration initialization in
>> the @PostConstruct of the @Singleton, this issue shouldn't exist.
>>
>> Can you paste the stacktrace of your NPE?
>>
>>
>> --
>> David Blevins
>> http://twitter.com/dblevins
>> http://www.tomitribe.com
>>
>> On Mar 7, 2015, at 3:51 AM, Matej <[email protected]> wrote:
>>
>> > Hi everybody.
>> >
>> > We have an annoying problem on our production system. We have an
>> > Configuration Singleton which reads config things from DB. Then in one
>> MDB
>> > we inject this Singleton to control operation based on configs. Our
>> problem
>> > is that the system is quite heavely loadded and while the system
>> startups
>> > already MDB recievs onMessage events while the Singleton still
>> initliazes.
>> > Which produces some NPEs and system doesn't boot.
>> >
>> > The depneds on annotation seems not to help. We are doing BEAN
>> conncurency
>> > management could this be the issue? And the Singleton has an
>> Postconstruct
>> > annotation.
>> >
>> > Anyone has any pattern or tips how to handle this type of scenario.
>> >
>> > BR
>> >
>> > Matej
>>
>>
>
