[infinispan-dev] CacheEntry vs. Metadata

Hi, I was already several times looking on the class hierarchy of CacheEntry and its descendants. Since the documentation of those interfaces is usually a one liner, I'd like to ask for the big picture: So we have CacheEntry, which implements MetadataAware - therefore, it contains a metadata, which define lifespan, maxIdle time and version. However, even the CacheEntry interface itself contains getters for lifespan and idle time and MortalCacheEntry hosts the fields - so I see that there's some duplication with the Metadata object. Beyond the expiration-related stuff (and common key - value getters), CacheEntry has several methods querying and manipulating its state - isChanged, isValid, isRemoved etc. It's a bit confusing that this is presented not as a single state but rather a matrix of boolean states. When I've tried to implement EntryProcessor several weeks ago (I've stopped the attempts since this should be implemented in Infinispan 8), I had quite a hard time figuring out which should be set and how in case I want to update/remove the entry. undelete() and skipLookup() are not obvious, either. Is the reason for having Immortal/Mortal/Transient/TransientMortal entries + Metadata* versions + *Values to optimally use memory? Then there are the ReadCommitted and RepeatableRead entries - are these ever stored in data container, or just in context? What's the exact relation between those implementing InternalCacheEntry and MVCCEntry? Then there's the DeltaAwareCacheEntry - this does not fit to the image for me at all. I am also not sure about the relation of EmbeddedMetadata and InternalMetadataImpl Thanks for your insight! Radim -- Radim Vansa <rvansa(a)redhat.com&gt; JBoss Performance Team