JdbcPollingChannelAdapter: Poll database manually only

Question

I have a JdbcPollingChannelAdapter which reads data via JDBC. I want to make it poll manually (using a commandChannel). It should never poll automatically, and it should run immediately when I trigger a manual poll.

Below I am using a poller which runs every 24 hours to get the channel running at all. I cannot use a cronExpression that never fires as in Quartz: Cron expression that will never execute since Pollers.cronExpression() takes no year.

@Bean
public MessageSource<Object> jdbcMessageSource() {
    return new JdbcPollingChannelAdapter(this.dataSource, "SELECT...");
}

@Bean
public IntegrationFlow jdbcFlow() {
    return IntegrationFlows
            .from(jdbcMessageSource(),
                    spec -> spec.poller(
                        Pollers.fixedRate(24, TimeUnit.HOURS)))
            .handle(System.out::println)
            .get();
}

score 2 · Accepted Answer · answered Apr 27 '17 at 14:08

Well, you go right way about JdbcPollingChannelAdapter and commandChannel, but you don't have configure SourcePollingChannelAdapter as you do with that IntegrationFlows.from(jdbcMessageSource().

What you need is really the jdbcMessageSource(), but to poll it manually you should configure command-based flow:

@Bean
public IntegrationFlow jdbcFlow() {
    return IntegrationFlows
            .from("commandChannel")
            .handle(jdbcMessageSource(), "receive")
            .handle(System.out::println)
            .get();
}

Exactly that receive() is called from the SourcePollingChannelAdapter on the timing basis.

JdbcPollingChannelAdapter: Poll database manually only

1 Answers1