How to wait for an Apache Camel JDBC job to finish

Question

I have a loop in my code that generates apache camel flows. However, each of these jobs needs to Poll from an Oracle database, and it leads to a Maximum Number of Sessions per user error. The reason is that these jobs are async, thus cause the app to reach its limit on the number of connections to the database. Therefore, I need a way to wait for the completion of a flow and then fire the next one. I was wondering if there was a way to do that? I tried to use Thread.sleep at the end of each loop, but it did not work.

for (int i=0; i<tasks.size(); i++) {
    DataStore sourceStore = dataStores.get(tasks.get(i));
    DataSource source = sourceStore.getDataSource();
    DefaultRegistry registry = new DefaultRegistry();
    registry.bind(tasks.get(i).getName(), source);
    CamelContext context = new DefaultCamelContext(registry);
    try {
        context.addRoutes(new RouteBuilder() {
            @Override
            public void configure() throws Exception {
                from ("direct:start")
                .to("jdbc:" + tasks.get(i).getSourceDataStoreName())
                .split(body())
                // some other job
                ;
                                                }
            });
        } catch (Exception e) {
        e.printStackTrace();
    }
    context.start();                
    ProducerTemplate producerTemplate = context.createProducerTemplate();
    producerTemplate.sendBody("direct:start", sourceStore.getQuery(tasks.get(i)));
    //Thread.sleep(40000); // did not work
}

Answer 1

I think you should try onCompletion. Accordind to documentation, route after onCompletion() is only invoked when the original route is complete. You can do your job after onCompletion(), for example, you can send somewhere result of your task.

There is my simple onCompletion() example:

context.addRoutes(new RouteBuilder()
{

        @Override
        public void configure() throws Exception
        {

            from("timer://mytimer?repeatCount=2&fixedRate=true&period=3000")
                    .process(exchange -> {
                        System.out.println("Thread will sleep 2s");
                        Thread.sleep(2000);
                    }).onCompletion().process(exchange -> System.out.println("After completion"));
        }
});