How can I check if a queue is empty and then stop the apache camel route that os listening to the queue

Question

I have an apache camel route that will be started by a process. Once the route is started it will process all of the messages on the queue. I want to stop the route once the queue is emptied out, so is it possible to do it in camel and maybe provide a short example.

Answer 1

This is the approach that worked for me:

Route configuration:

from("direct:start")
    .routeId("testRoute")
    .setHeader("shutDownRoute").method(myBean)
    // you business logic 
    .choice()
        when(header("shutDownRoute").isEqualTo(true))
            .toD("controlbus:route?async=true&routeId=${routeId}&action=stop")
        end();

MyBean.java

@Service
public class MyBean {
  private JmsTemplate jmsTemplate;
  private String queueName;

  @Autowired
  public MyBean (JmsTemplate jmsTemplate, String queueName) {
    this.jmsTemplate = jmsTemplate;
    this.queueName = queueName;
  }

  private Message browseMessageFromQueue(String queueName) {
    BrowserCallback<Message> browserCallback = 
          (session, browser) -> {
        Enumeration<?> enumeration = browser.getEnumeration();
        if(enumeration.hasMoreElements()) {
            return (Message) enumeration.nextElement();
        }
        return null;
    };
    return jmsTemplate.browse(queueName, browserCallback);
  }

  @Handler
  public boolean isLastMessage() {
    Message message = browseMessageFromQueue(queueName);
    return message == null; 
  }
}