I'm trying to create cache with auto refreshing elements using org.cache2k library. For example I define element loader with duration of 5 seconds. I set expire time 5 seconds. And I set keepDataAfterExpired and refreshAhead options to true.
First calling get method lasts approximatelly 5 seconds. It's ok. Then I expect that element will be expired and auto reloaded during next 15 seconds and second get will take element without delay. But my output is:
result
5011
result
5000
Second get as first lasts also 5 seconds as first. My goal is to make element refresh automatically and only first get would take delay. Is it reachable and how? Thank you.
static String expensiveOperation(String name) throws InterruptedException {
Thread.sleep(5000);
return "result";
}
public static void main (String... args) throws InterruptedException {
Cache<String,String> cache = new Cache2kBuilder<String, String>() {}
.expireAfterWrite(5000, TimeUnit.MILLISECONDS) // expire/refresh after 5 seconds
.keepDataAfterExpired(true)
.refreshAhead(true) // keep fresh when expiring
.loader(s->expensiveOperation(s)) // auto populating function
.build();
Instant i1 = Instant.now();
System.out.println(cache.get("a"));
Instant i2 = Instant.now();
System.out.println(Duration.between(i1,i2).toMillis());
Thread.sleep(15000);
Instant i11 = Instant.now();
System.out.println(cache.get("a"));
Instant i22 = Instant.now();
System.out.println(Duration.between(i11,i22).toMillis());
