[infinispan-dev] AdvancedCache.put with Metadata parameter

Mon Apr 8 07:36:28 EDT 2013

On Apr 8, 2013, at 1:11 PM, Dan Berindei <dan.berindei at gmail.com> wrote:

> 
> 
> 
> On Mon, Apr 8, 2013 at 1:44 PM, Galder Zamarreño <galder at redhat.com> wrote:
> 
> On Apr 8, 2013, at 12:35 PM, Galder Zamarreño <galder at redhat.com> wrote:
> 
> >
> > On Apr 8, 2013, at 11:17 AM, Manik Surtani <msurtani at redhat.com> wrote:
> >
> >> All sounds very good. One important thing to consider is that the reference to Metadata passed in by the client app will be tied to the ICE for the entire lifespan of the ICE.  You'll need to think about a defensive copy or some other form of making the Metadata immutable (by the user application, at least) the moment it is passed in.
> >
> > ^ Excellent point, it could be a nightmare if users could change the metadata reference by the ICE at will. I'll have a think on how to best achieve this.
> 
> ^ The metadata is gonna have to be marshalled somehow to ship to other nodes, so that could be a way to achieve it, by enforcing this somehow. When the cache receives it, it can marshaller/unmarshall it to make a copy
> 
> 
> If Metadata is just an interface, nothing is stopping the user from implementing maxIdle() to return Random.maxLong(). Besides, local caches need to support Metadata as well, and we shouldn't force serialization/deserialization for local caches.
> 
> So I think we'd be better off documenting that Metadata objects should not change after they are inserted in the cache, just like keys and values. 
> 
>  
> One way would be to make Metadata extend Serializable, but not keen on that. Another would be to somehow force the interface to define the Externalizer to use (i.e. an interface method like getExternalizer()), but that's akward when it comes to unmarshalling… what about forcing the Metadata object to be provided with a @SerializeWith annotation?
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> Any other ideas?
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> Why force anything? I think Metadata instances should be treated just like keys and values, so they should be able to use Externalizers (via @SerializeWith), Serializable, or Externalizable, depending on the user's requirements.

^ I agree. 

What do you think of my suggestion in the other email to separate both concerns and somehow enforce a copy of the object to be provided instead?

> 
>  
> >
> > Cheers,
> >
> >>
> >> On 8 Apr 2013, at 09:24, Galder Zamarreño <galder at redhat.com> wrote:
> >>
> >>> Hi all,
> >>>
> >>> As mentioned in http://lists.jboss.org/pipermail/infinispan-dev/2013-March/012348.html, in paralell to the switch to Equivalent* collections, I was also working on being able to pass metadata into Infinispan caches. This is done to better support the ability to store custom metadata in Infinispan without the need of extra wrappers. So, the idea is that InternalCacheEntry instances will have a a reference to this Metadata.
> >>>
> >>> One of that metadata is version, which I've been using as test bed to see if clients could pass succesfully version information via metadata. As you already know, Hot Rod requires to store version information. Before, this was stored in a class called CacheValue alongside the value itself, but the work I've done in [1], this is passed via the new API I've added in [2].
> >>>
> >>> So, I'd like to get some thoughts on this new API. I hope that with these new put/replace versions, we can get rid of the nightmare which is all the other put/replace calls taking lifespan and/or maxIdle information. In the end, I think there should be two basic puts:
> >>>
> >>> - put(K, V)
> >>> - put(K, V, Metadata)
> >>>
> >>> And their equivalents.
> >>>
> >>> IMPORTANT NOTE 1: The implementation details are bound to change, because the entire Metadata needs to be stored in InternalCacheEntry, not just version, lifespan..etc. I'll further develop the implementation once I get into adding more metadata, i.e. when working on interoperability with REST. So, don't pay too much attention to the implementation itself, focus on the AdvancedCache API itself and let's refine that.
> >>>
> >>> IMPORTANT NOTE 2: The interoperability work in commit in [1] is WIP, so please let's avoid discussing it in this email thread. Once I have a more final version I'll send an email about it.
> >>>
> >>> Apart from working on enhancements to the API, I'm now carry on tackling the interoperability work with aim to have an initial version of the Embedded <-> Hot Rod interoperability as first step. Once that's in, it can be released to get early feedback while the rest of interoperability modes are developed.
> >>>
> >>> Cheers,
> >>>
> >>> [1] https://github.com/galderz/infinispan/commit/a35956fe291d2b2dc3b7fa7bf44d8965ffb1a54d
> >>> [2] https://github.com/galderz/infinispan/commit/a35956fe291d2b2dc3b7fa7bf44d8965ffb1a54d#L10R313
> >>> --
> >>> Galder Zamarreño
> >>> galder at redhat.com
> >>> twitter.com/galderz
> >>>
> >>> Project Lead, Escalante
> >>> http://escalante.io
> >>>
> >>> Engineer, Infinispan
> >>> http://infinispan.org
> >>>
> >>>
> >>> _______________________________________________
> >>> infinispan-dev mailing list
> >>> infinispan-dev at lists.jboss.org
> >>> https://lists.jboss.org/mailman/listinfo/infinispan-dev
> >>
> >> --
> >> Manik Surtani
> >> manik at jboss.org
> >> twitter.com/maniksurtani
> >>
> >> Platform Architect, JBoss Data Grid
> >> http://red.ht/data-grid
> >>
> >>
> >> _______________________________________________
> >> infinispan-dev mailing list
> >> infinispan-dev at lists.jboss.org
> >> https://lists.jboss.org/mailman/listinfo/infinispan-dev
> >
> >
> > --
> > Galder Zamarreño
> > galder at redhat.com
> > twitter.com/galderz
> >
> > Project Lead, Escalante
> > http://escalante.io
> >
> > Engineer, Infinispan
> > http://infinispan.org
> >
> 
> 
> --
> Galder Zamarreño
> galder at redhat.com
> twitter.com/galderz
> 
> Project Lead, Escalante
> http://escalante.io
> 
> Engineer, Infinispan
> http://infinispan.org
> 
> 
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> 
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--
Galder Zamarreño
galder at redhat.com
twitter.com/galderz

Project Lead, Escalante
http://escalante.io

Engineer, Infinispan
http://infinispan.org