EventNotifier

The event notifier org.apache.camel.spi.EventNotifier is used to get notified about events within the CamelContext. For example, when a route is started or stopped. The events are collected independently from the CamelContext (routes, services, exchanges, and so on). This means that the notifier doesn’t interfere with the rest of Camel, and the events can be processed independently for logging, data offloading or other type of actions.

Type of Events

The following CamelEvents are available:

  • CamelEvent

    • CamelContextEvent

      • CamelContextInitializedEvent

      • CamelContextInitializingEvent

      • CamelContextReloadedEvent

      • CamelContextReloadFailureEvent

      • CamelContextReloadingEvent

      • CamelContextResumedEvent

      • CamelContextResumeFailureEvent

      • CamelContextResumingEvent

      • CamelContextRoutesStartedEvent

      • CamelContextRoutesStartingEvent

      • CamelContextRoutesStoppedEvent

      • CamelContextRoutesStoppingEvent

      • CamelContextStartedEvent

      • CamelContextStartingEvent

      • CamelContextStartupFailureEvent

      • CamelContextStopFailureEvent

      • CamelContextStoppedEvent

      • CamelContextStoppingEvent

      • CamelContextSuspendedEvent

      • CamelContextSuspendingEvent

    • ExchangeEvent

      • ExchangeAsyncProcessingStartedEvent

      • ExchangeCompletedEvent

      • ExchangeCreatedEvent

      • ExchangeFailedEvent

      • ExchangeFailureEvent

      • ExchangeFailureHandledEvent

      • ExchangeFailureHandlingEvent

      • ExchangeRedeliveryEvent

      • ExchangeSendingEvent

      • ExchangeSentEvent

    • FailureEvent

    • RouteEvent

      • RouteAddedEvent

      • RouteReloadedEvent

      • RouteRemovedEvent

      • RouteStartedEvent

      • RouteStartingEvent

      • RouteStoppedEvent

      • RouteStoppingEvent

    • ServiceEvent

      • ServiceStartupFailureEvent

      • ServiceStopFailureEvent

    • StepEvent

      • StepCompletedEvent

      • StepFailedEvent

      • StepStartedEvent

See the Javadoc of the org.apache.camel.spi.CamelEvent for more details.

Collect Events

To collect events a class is needed that extends the EventNotifierSupport class.

public class MyCollector extends EventNotifierSupport {

    protected Logger log = LoggerFactory.getLogger(getClass());

    @Override
    public void notify(CamelEvent event) throws Exception {

        log.info("Event: " event.getType().name());

    }

}

Then you can enable the notifier:

context.getManagementStrategy().addEventNotifier(new MyCollector());

Collect Specific Events

By default you get notified by all events. It’s however possible to exclude certain groups of events to get only the group of event you are interest in.

In the following example we collect only StepEvents:

public class StepCollector extends EventNotifierSupport {
    protected Logger log = LoggerFactory.getLogger(getClass());

    @Override
    public void notify(CamelEvent event) throws Exception {

        // Cast CamelEvent to StepEvent
        CamelEvent.StepEvent stepEvent = (CamelEvent.StepEvent) event;

        // Get detailed information from the StepEvent
        String eventType = stepEvent.getType().name();
        String stepId = stepEvent.getStepId();
        String body = stepEvent.getExchange().getMessage().getBody(String.class);

        log.info("Event Type:\t\t" + eventType);
        log.info("Step ID:\t\t\t" + stepId);
        log.info("Message Body:\t\t " + body);

    }

}

Then you can enable the notifier for steps by excluding other groups:

//Create eventNotifier that only collects stepEvents
StepCollector stepCollector = new StepCollector();
stepCollector.setIgnoreCamelContextEvents(true);
stepCollector.setIgnoreCamelContextInitEvents(true);
stepCollector.setIgnoreExchangeEvents(true);
stepCollector.setIgnoreRouteEvents(true);
stepCollector.setIgnoreServiceEvents(true);
stepCollector.setIgnoreStepEvents(false);

//Add the Event Notifier to the Camel Context
context.getManagementStrategy().addEventNotifier(stepCollector);
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