Give Priority to SFTP Remote Directories - spring

Question

Using single SFTP channel I need to process two remote directories lowpriority and highprioiry but lowpriority files pick after the highpriority .
please let know how handle multiple directories in SFTP inbound adapter with single channel ?
We can do using https://docs.spring.io/spring-integration/reference/html/sftp.html#sftp-rotating-server-advice Rotation Service advice in Spring 5.1.2 Release but what about 4.3.12 Release.?

Answer 1

It is not available in 4.3.x; the feature was added in 5.0.7.
It needs infrastructure changes so it will be hard to replicate with custom code in 4.3.x.
You could use two adapters and stop/start them as necessary.
EDIT
Here is one solution; the advice on the primary flow starts the secondary flow when no new files are found. The secondary flow runs just once, then restarts the primary flow; and the cycle continues...
#SpringBootApplication
public class So54329898Application {
public static void main(String[] args) {
SpringApplication.run(So54329898Application.class, args);
}
#Bean
public IntegrationFlow primary(SessionFactory<LsEntry> sessionFactory) {
return IntegrationFlows.from(Sftp.inboundAdapter(sessionFactory)
.localDirectory(new File("/tmp/foo"))
.remoteDirectory("foo/foo"), e -> e
.poller(Pollers.fixedDelay(5_000, 5_000)
.advice(startSecondaryAdvice())))
.channel("channel")
.get();
}
#Bean
public IntegrationFlow secondary(SessionFactory<LsEntry> sessionFactory) {
return IntegrationFlows.from(Sftp.inboundAdapter(sessionFactory)
.localDirectory(new File("/tmp/foo"))
.remoteDirectory("foo/bar"), e -> e
.poller(Pollers.trigger(oneShotTrigger(sessionFactory)))
.autoStartup(false))
.channel("channel")
.get();
}
#Bean
public IntegrationFlow main() {
return IntegrationFlows.from("channel")
.handle(System.out::println)
.get();
}
#Bean
public Advice startSecondaryAdvice() {
return new StartSecondaryWhenPrimaryIdle();
}
#Bean
public FireOnceTrigger oneShotTrigger(SessionFactory<LsEntry> sessionFactory) {
return new FireOnceTrigger((Lifecycle) primary(sessionFactory));
}
public static class StartSecondaryWhenPrimaryIdle extends AbstractMessageSourceAdvice
implements ApplicationContextAware {
private ApplicationContext applicationContext;
#Override
public boolean beforeReceive(MessageSource<?> source) {
return true;
}
#Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
this.applicationContext = applicationContext;
}
#Override
public Message<?> afterReceive(Message<?> result, MessageSource<?> source) {
if (result == null) {
System.out.println("No more files on primary; starting single shot on secondary");
this.applicationContext.getBean("primary", Lifecycle.class).stop();
this.applicationContext.getBean("secondary", Lifecycle.class).stop();
this.applicationContext.getBean(FireOnceTrigger.class).reset();
this.applicationContext.getBean("secondary", Lifecycle.class).start();
}
return result;
}
}
public static class FireOnceTrigger implements Trigger {
private final Lifecycle primary;
private volatile boolean done;
public FireOnceTrigger(Lifecycle primary) {
this.primary = primary;
}
#Override
public Date nextExecutionTime(TriggerContext triggerContext) {
if (done) {
System.out.println("One shot on secondary complete; restarting primary");
this.primary.start();
return null;
}
done = true;
return new Date();
}
public void reset() {
done = false;
}
}
}