Release CacheLoaders.asyncReload

Original issue created by electrum on 2013-12-30 at 09:30 PM

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The documentation for CacheLoader.refreshAfterWrite() recommends overriding reload() with an asynchronous version. We use the following in many places and think it could be a good addition to Guava:

public abstract class BackgroundCacheLoader<K, V>         extends CacheLoader<K, V> {     private final ListeningExecutorService executor;

protected BackgroundCacheLoader(ListeningExecutorService executor)
{
    this.executor = checkNotNull(executor, "executor is null");
}

@Override
public final ListenableFuture<V> reload(final K key, V oldValue)
        throws Exception
{
    return executor.submit(new Callable<V>()
    {
        @Override
        public V call()
                throws Exception
        {
            return load(key);
        }
    });
}

}

[noahlz]

You should totally update the Caches Explained wiki to mention this API! 💯

[Davetron]

Any examples on how to use asyncReloading?

I’m using CacheBuilder with Spring cache. Presumably it’s automagically creating a default LoadingCache somewhere along the way to the @Cacheable but it’d be nice to configure a cache that does async reloading without having to override CacheLoader.reload()