code: private RingbufferContainer<InternalEventJournalCacheEvent, Object> getRingbufferOrNull(
              EventJournalConfig journalConfig, ObjectNamespace namespace, int partitionId) {
          RingbufferService ringbufferService = getRingbufferService();
          RingbufferContainer<InternalEventJournalCacheEvent, Object> container
                  = ringbufferService.getContainerOrNull(partitionId, namespace);
          if (container != null) {
              return container;
          }
  
          return journalConfig != null ? getOrCreateRingbufferContainer(namespace, partitionId, journalConfig) : null;
      }
docs: Gets or creates a ringbuffer for an event journal or returns {@link null} if no
  event journal is configured, it is disabled or not available.
  
  @param journalConfig the event journal configuration for this specific cache
  @param namespace     the cache namespace, containing the full prefixed cache name
  @param partitionId   the cache partition ID
  @return the cache partition event journal or {@code null} if no journal is configured for this cache
  @throws CacheNotExistsException if the cache configuration was not found
  @see #getEventJournalConfig(ObjectNamespace)