[EMAIL PROTECTED] wrote:
>
> > Raphael Luta wrote:
> >
I never wrote what is below. This quote is from Santiago. Please take
care when quoting, misquotations make following the thread real difficult...
> > That is a memory cache. The problem is that the PSML should be
> > fetched/parsed atomically, and then stored in a memory cache such
> > as the Turbine one, to avoid race conditions if we use frames. This
> > is true of most external resources, that should be fetched atomically
> > and then cached until they expire.
> >
> > With regards to the retrieval of external resources (basically URLs)
> > Jetspeed needs an API that respect several requirements:
> >
> > - No resource will be fetched in parallel by more than one thread.
> > One thread will fetch it and the others will wait until completion.
> > - No resource will be fetched again until it expires.
> > - A writable resource will expire as soon as it is written.
> > - Calls to check availability, get a Reader and get a Writer on the
> > resource.
> > GetObject for non character stream objects.
> > - I notice now that we need a hook for Fetching, depending on the type
> > of object (e.g. parsing/unmarshalling XML is included in the process)
>
> This reminds me of the service concept we discussed some time ago.
> Similarly to other services, we could define a CacheService interface
> for which different implementations may exist.
>
Turbine GlobalCacheService exists already we can easily provide
additional implementation if needed.
However note that we don't want a single cache instance for the whole
application, we may need different cache instance of different
implementations running at the same time for caching different
kind of elements. The Turbine service API does address this as such
since it's singleton based but it may be possible to extend it.
I don't know yet but it first require a careful analysis
of what needs to be cached and what are the desired caching properties
for each of these elements.
[ Quick aside: I didn't answer to your concerns on the MRU
performance because the more I think about it, the more I feel this
is barking at the wrong tree: if you're considering a high-performance
high-spec setup you're also considering DBMS persistence of PSML
and caching will be done at the element level, not a serialized XML
file ]
--
Rapha�l Luta - [EMAIL PROTECTED]
--
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