Issues with initializing service class that has dependency on running application on startup (play 2.4 / scala) - scala

Question

I am currently digging into using Quartz in our play 2.4 application.
Initially, I tried initializing everything through Global object, and everything worked perfectly.
Now, I an trying to move away from Global utilize modules infrastructure.
Here is what I have until now.
JobSchedulingService
#Singleton
class JobSchedulingService #Inject()(lifecycle: ApplicationLifecycle) extends ClassLogger{
lazy val schedulerFactory = current.injector.instanceOf[StdSchedulerFactory]
lazy val scheduler = schedulerFactory.getScheduler
/**
* Let's make sure that scheduler shuts down properly
*/
lifecycle.addStopHook{ () =>
Future.successful{
if (scheduler.isStarted) {
scheduler.shutdown(true)
}
}
}
protected def init() : Unit = {
logger.info("Initializing scheduler...")
scheduler.start()
}
init()
}
SchedulerModule - here for initialization of the service above.
class SchedulerModule extends AbstractModule{
override def configure(): Unit = {
bind(classOf[JobSchedulingService]).asEagerSingleton
}
}
And in my application.conf I added:
play.modules.enabled += "scheduling.modules.SchedulerModule"
It looks pretty strait forward. However, when the app starts I am getting an exception:
2016-03-23 00:07:42,173 INFO s.JobSchedulingService - Initializing
scheduler... 2016-03-23 00:07:42,213 ERROR application -
! #6pfp72mh6 - Internal server error, for (GET) [/] ->
play.api.UnexpectedException: Unexpected exception[CreationException:
Unable to create injector, see the following errors:
1) Error injecting constructor, java.lang.RuntimeException: There is
no started application at
scheduling.JobSchedulingService.(JobSchedulingService.scala:15)
at
scheduling.modules.SchedulerModule.configure(SchedulerModule.scala:11)
(via modules: com.google.inject.util.Modules$OverrideModule ->
scheduling.modules.SchedulerModule) while locating
scheduling.JobSchedulingService
...
The thing is, in our app, the scheduler is based of off persistence job storage and should restart when the application restarts. Again, when I did it through Global, it worked perfectly.
How do I get around this problem? What is the correct way to initialize an instance on startup?
Thanks,

Answer 1

You should probably be using the dependency injection for everything. Inject the scheduler like..
class JobSchedulingService #Inject()(lifecycle: ApplicationLifecycle, schedulerFactory: StdSchedulerFactory) extends ClassLogger{
lazy val scheduler = schedulerFactory.getScheduler

Answer 2

Hmmm...
I think I just resolved it.
It seems like the problem was not the actual initialization of a class, but this line:
lazy val schedulerFactory = current.injector.instanceOf[StdSchedulerFactory]
once I changed it to:
lazy val schedulerFactory = new StdSchedulerFactory
it started working.
May that will help somebody