How to correctly specify reference manager configuration

[Bios-Marcel]

We are currently using Spring Boot.

Trying to manually specify the LazyReferenceManager manually as a bean will work, BUT will cause an exception once LazyReferenceManager.Static is automatically initialised when accessing LazyReferenceManager.get().

I initialised it like this:

  @Bean(
      // Wird von EclipseStore vorgeschrieben
      name = "org.eclipse.store:name=LazyReferenceManager",
      // Braucht nicht destroyed zu werden
      destroyMethod = "" )
  LazyReferenceManager lazyReferenceManager()
  {
    // wir verzichten auf das clearen der Referenzen, um die Tests schneller auszuführen.
    final LazyReferenceManager lazyReferenceManager = LazyReferenceManager.New(
        lazyReference -> true,
        Integer.MAX_VALUE,
        0
    );
    // Doesn't matter whether I call this, error occurs anyway.
    LazyReferenceManager.set( lazyReferenceManager );
    return lazyReferenceManager;
  }

The same issue occurs when calling the example from the documentation:

LazyReferenceManager.set(LazyReferenceManager.New(
	Lazy.Checker(
		Duration.ofMinutes(30).toMillis(), // timeout of lazy access
		0.75                               // memory quota
	)
);

It is unclear to me how to correctly configure this. No matter what I do, I end up with this Exception on way or another:

javax.management.InstanceAlreadyExistsException: org.eclipse.store:name=LazyReferenceManager
	at java.management/com.sun.jmx.mbeanserver.Repository.addMBean(Repository.java:322) ~[?:?]
	at java.management/com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerWithRepository(DefaultMBeanServerInterceptor.java:1848) ~[?:?]
	at java.management/com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerDynamicMBean(DefaultMBeanServerInterceptor.java:945) ~[?:?]
	at java.management/com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerObject(DefaultMBeanServerInterceptor.java:880) ~[?:?]
	at java.management/com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerMBean(DefaultMBeanServerInterceptor.java:315) ~[?:?]
	at java.management/com.sun.jmx.mbeanserver.JmxMBeanServer.registerMBean(JmxMBeanServer.java:523) ~[?:?]
	at org.eclipse.serializer.monitoring.MonitoringManager$JMX.registerMonitor(MonitoringManager.java:135) ~[base-2.0.0.jar:?]
	at org.eclipse.serializer.reference.LazyReferenceManager$Default.<init>(LazyReferenceManager.java:227) ~[base-2.0.0.jar:?]
	at org.eclipse.serializer.reference.LazyReferenceManager.New(LazyReferenceManager.java:166) ~[base-2.0.0.jar:?]
	at org.eclipse.serializer.reference.LazyReferenceManager.New(LazyReferenceManager.java:151) ~[base-2.0.0.jar:?]
	at org.eclipse.serializer.reference.LazyReferenceManager.New(LazyReferenceManager.java:142) ~[base-2.0.0.jar:?]
	at org.eclipse.serializer.reference.LazyReferenceManager.New(LazyReferenceManager.java:127) ~[base-2.0.0.jar:?]

I was assuming this MIGHT be a bug in EclipseStore, but I might just not be knowledgable enough regarding the bean topic :D

If it's not a bug, maybe we could add an example for configuring the LazyReferenceManager via Spring.

[Bios-Marcel]

For now I am using this BEAUTIFUL hack:

  static
  {
    // Hack to init and shut down the default instance, as we can't register a custom one otherwise.
    LazyReferenceManager.get().stop();

    // wir verzichten auf das clearen der Referenzen, um die Tests schneller auszuführen.
    final LazyReferenceManager lazyReferenceManager = LazyReferenceManager.New(
        lazyReference -> true,
        Integer.MAX_VALUE,
        0
    );
    LazyReferenceManager.set( lazyReferenceManager );
  }

I am not sure whether that's a good idea though.

[zdenek-jonas]

Edit:

Generally I would use:

@SpringBootApplication
public class SimpleJokesApplication {
  public static void main(String... args) {
    LazyReferenceManager.set(LazyReferenceManager.New(
            Lazy.Checker(
                    Duration.ofMinutes(30).toMillis(), // timeout of lazy access
                    0.75                               // memory quota
            )));
    SpringApplication.run(SimpleJokesApplication.class, args);
  }

}

LazyReferenceManager is a singleton. Therefore, it must be defined before the storage manager starts.

[zdenek-jonas]

#322

There is a bug in JMX integration, but it should not impact the registration of LazyReferenceManager. I will add a customizer in the code, which should help ensure the code is executed before storage initialization.

[zdenek-jonas]

main...zj/spring_custom_initializer_1024

Will this approach be helpful?

[zdenek-jonas]

#323

[Bios-Marcel]

Well, you mentioned that there is a bug in the integration. Due to this I still run into the exception even with a custom component. So I guess it doesn't really make a difference?

[zdenek-jonas]

The bug is only in the JMX registration for monitoring, so the configuration should work as expected. We will address this JMX registration issue.