Handling events using JobManager. More info here: http://sling.apache.org/documentation/tutorials-how-tos/how-to-manage-events-in-sling.html

SampleEventHandler.java

/* This OSGi service listens for events and creates a job for each one matching some conditions. */
@Component
@Service
@Properties({
  	// choose appropriate topic values
	@Property(name = EventConstants.EVENT_TOPIC, value = {
		SlingConstants.TOPIC_RESOURCE_CHANGED,
		SlingConstants.TOPIC_RESOURCE_ADDED,
		SlingConstants.TOPIC_RESOURCE_REMOVED
	})
})
public class SampleEventHandler implements EventHandler {

	@Reference
	private JobManager jobManager;

	@Override
	public void handleEvent(Event event) {
		String path = (String) event.getProperty(SlingConstants.PROPERTY_PATH);
		String resourceType = (String) event.getProperty(SlingConstants.PROPERTY_RESOURCE_TYPE);
		if (StringUtils.contains(path, "/jcr:content/configParsys/")) {
			Map<String, Object> jobProperties = new HashMap<String, Object>();
			// fill job properties map with useful values
			jobProperties.put("path", path);
			jobProperties.put("resourceType", resourceType);
			jobManager.addJob(SampleJobConsumer.JOB_TOPIC, null, jobProperties);
		}
	}
}

SampleJobConsumer.java

/* This OSGi service consumes job created by the event listener above. */
@Component
@Service
@Properties({
	@Property(name = JobConsumer.PROPERTY_TOPICS, value = SampleJobConsumer.JOB_TOPIC)
})
public class SampleJobConsumer implements JobConsumer {

	public static final String JOB_TOPIC = "com/cognifide/cq/some/job/topic";
	
	@Override
	public JobResult process(Job job) {
		String path = job.getProperty("path", String.class);
		String resourceType = job.getProperty("resourceType", String.class);
		// do something clever here
		return JobResult.OK;
	}
}

How do you execute it?, I mean, who is the responsible to create an instance of SampleEventHandler so that a new job can be put into the queue?