Spring file Inbound adapters - priority to directories with single channels - spring

Question

Using single inbound channel I need to process two directories lowpriority and highprioiry but lowpriority files pick after the highpriority .
Any one know how handle multiple directories in file inbound adapter with single channel ?
#Bean
public IntegrationFlow processFileFlow() {
return pushFileForProcess(lowDirectory
,"processFile"
, "fileInputChannel");
}
private IntegrationFlow pushFileForProcess(String processDir, String methodName, String adapterName) {
String fileProcessor = "fileProcessor";
return IntegrationFlows
.from(Files.inboundAdapter(Paths.get(processDir).toFile())
.regexFilter(FILE_PATTERN_REGEX)
.preventDuplicates(false),
e -> e.poller(Pollers.fixedDelay(j.getPollerIntervalMs())
.maxMessagesPerPoll(j.getPollerMaxMsgs())
.errorChannel("errorChannel")) // moves processed files
.id(adapterName))
.handle(fileProcessor, methodName).get();
}

Answer 1

Use a Smart Poller Advice to reconfigure the FileReadingMessageSource when the poll returns no files for the high priority directory.
Presumably you should reconfigure it back on each low-priority poll (successful or not).
EDIT
Example:
#SpringBootApplication
public class So53868122Application {
private static final File HIGH = new File("/tmp/high");
private static final File LOW = new File("/tmp/low");
public static void main(String[] args) {
HIGH.mkdir();
LOW.mkdir();
SpringApplication.run(So53868122Application.class, args);
}
#Bean
public IntegrationFlow flow() {
return IntegrationFlows.from(Files.inboundAdapter(HIGH),
e -> e.poller(Pollers.fixedDelay(5_000)
.advice(dirSwitcher())))
.handle(System.out::println)
.get();
}
#Bean
public Advice dirSwitcher() {
return new HighLowPollerAdvice();
}
public static class HighLowPollerAdvice extends AbstractMessageSourceAdvice {
private boolean isHigh = true;
#Override
public Message<?> afterReceive(Message<?> result, MessageSource<?> source) {
if (this.isHigh && result == null) {
System.out.println("No results from " + HIGH + ", switching to " + LOW);
this.isHigh = false;
((FileReadingMessageSource) source).setDirectory(LOW);
}
else if (!this.isHigh) {
System.out.println("After one poll of " + LOW + " that returned "
+ (result == null ? "no file" : result.getPayload()) + ", switching to " + HIGH);
this.isHigh = true;
((FileReadingMessageSource) source).setDirectory(HIGH);
}
return result;
}
}
}