Perform action on expiry with Caffeine on Java

Question

I want to create a cache like so

Cache<String, File> cache = Caffeine.newBuilder()
                .expireAfterWrite(1, TimeUnit.MINUTES)
                .maximumSize(100)
                .build();

That i will populate with a temporary file like so,

File f = File.createTempFile("jobid_", ".json");
FileWriter fileWriter = new FileWriter(f);
fileWriter.write("text values 123");
fileWriter.close();


cache.put("jobid", f);

Now after 1 minute I understand that cache.getIfPresent("jobid") will return null, my question is that is there some way in which I can trigger another task when this entry expires - deleting the temporary file itself.

Any alternative solution works as well.

https://stackoverflow.com/questions/55045949/is-there-a-cacheentryexpiredlistener-for-caffeine-cache — terrorrussia-keeps-killing, Mar 09 '21 at 10:51

score 2 · Answer 1 · edited Mar 09 '21 at 16:19

2

Thanks to fluffy.

To implement the same, simple use the removalListener.

For my use case:

Cache<String, File> cache = Caffeine.newBuilder()
    .removalListener((String key, File file, RemovalCause cause) -> {
      file.delete();
    })
    .expireAfterWrite(3, TimeUnit.SECONDS)
    .maximumSize(100)
    .build();

solves the problem.

edited Mar 09 '21 at 16:19

Ben Manes

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answered Mar 09 '21 at 13:55

Abhiram Natarajan

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Perform action on expiry with Caffeine on Java

1 Answers1