Example For Bulk Load

[gyansatapathy]

I would really appreciate if you can show how to override the loadAll in cache loader?

[ben-manes]

Hi @gyansatapathy,

You can simply implement the method and the cache will invoke it on a bulk request.

Cache<UUID, User> users = Caffeine.newBuilder().build(new CacheLoader<UUID, User>() {
  public User load(UUID id) {
    return repository.getUserById(id);
  }
  public Map<UUID, User> loadAll(Set<UUID> ids) {
    return repository.getAllUsersById(ids);
  }
});

cache.get(Set.of(UUID.randomUUID(), UUID.randomUUID()));

You might also find the CacheLoader.bulk convenience function useful as a shorter syntax that delegates load(key) to the loadAll(keys) method.

Cache<UUID, User> users = Caffeine.newBuilder()
    .build(CacheLoader.bulk((Set<UUID> keys) -> repository.getAllUsersById(ids));

cache.get(Set.of(UUID.randomUUID(), UUID.randomUUID()));

[gyansatapathy]

Thanks for the quick response. The issue is tried overriding both the loadAll and load method . If I do cache.getAll(ids) it still calls the load method for every id in the list. Not sure what's wrong there.

I didn't try the second way you have mentioned here of only forcing the bulkLoad implementation. I will give it a shot.

[ben-manes]

An example in our test code is,

caffeine/caffeine/src/test/java/com/github/benmanes/caffeine/cache/LoadingCacheTest.java

Lines 182 to 192 in 317e647

	@Test(dataProvider = "caches")
	@CacheSpec(loader = { Loader.NEGATIVE, Loader.BULK_NEGATIVE },
	removalListener = { Listener.DEFAULT, Listener.REJECTING })
	public void getAll_absent(LoadingCache<Int, Int> cache, CacheContext context) {
	var result = cache.getAll(context.absentKeys());
	int count = context.absentKeys().size();
	int loads = context.loader().isBulk() ? 1 : count;
	assertThat(result).hasSize(count);
	assertThat(context).stats().hits(0).misses(count).success(loads).failures(0);
	}

That provides a configured cache using a bulk loader defined as,

caffeine/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/CacheSpec.java

Lines 498 to 509 in 317e647

	BULK_NEGATIVE {
	@Override public Int load(Int key) {
	throw new UnsupportedOperationException();
	}
	@Override public Map<Int, Int> loadAll(Set<? extends Int> keys) throws Exception {
	var result = new HashMap<Int, Int>(keys.size());
	for (Int key : keys) {
	result.put(key, NEGATIVE.load(key));
	}
	return result;
	}
	},

[gyansatapathy]

Hi @ben-manes I found out there was an issue in my classpath due to spring dependency management plugin as it was forcing an older version. Its working now. Thanks a ton.