Refactor CacheLoader API to make it thread safe ----------------------------------------------- Key: ISPN-6279 URL: https://issues.jboss.org/browse/ISPN-6279 Project: Infinispan Issue Type: Feature Request Components: Loaders and Stores Reporter: Sebastian Łaskawiec Priority: Minor Fix For: 9.0.0.Final h3. Introduction Currently {{CacheLoader}} thread safety can be easily compromised by broken implementations. We should provide a better implementation to make it more convenient and less error prone. h3. Problem statement CacheLoader API looks like this: {code} public interface AdvancedCacheLoader<K, V> extends CacheLoader<K, V> { ... void process(KeyFilter<? super K> filter, CacheLoaderTask<K, V> task, Executor executor, boolean fetchValue, boolean fetchMetadata); ... } {code} The CacheLoader implementation controls {{CacheLoaderTask}} as well as the number of threads used for processing (specified by {{Executor}}). If one wants to collect all keys (similarly to [AdvancedCacheLoader|https://github.com/infinispan/infinispan/blob/master/...]) it is very easy to hit concurrently issues while adding them to the set (See previous JIRAs: ISPN-3938 and ISPN-6276). h3. Solution The solution should take away currently control (Executor) and keyset (the simplest idea is to add it to {{CacheLoaderTask}}) from from the implementation. One of the ideas is to create a Lambda expression for pulling records from Cache Store. Note that similar changes will need to be performed to {{CacheWriter}} (to make it similar).