Re: Precondition support

From: Paul Sandoz <Paul.Sandoz_at_Sun.COM>
Date: Tue, 10 Apr 2007 12:57:44 +0200

Jerome Louvel wrote:
>> - Often you'll need to obtain the same data to compute an entity tag
>> and last modified value as you'll need to service the request
>> (should
>> the preconditions be met). You don't want to have to fetch the same
>> data multiple times so you'd want some way to cache it between the
>> getEntityTag/getLastModified/http method. However its not
>> clear which
>> of the methods will actually be called since the preconditions might
>> not be met so then you end up with data lifecycle issues. We
>> considered thread-local approaches to caching data but that has
>> implications on the container for thread management.
> Hmm, I don't understand why we should take this into account. Isn't this an
> internal issue for the POJOs that we are annotating? They could also
> implement late data loading mechanisms if necessary. The first method
> invoked (getLastMofidied/getEntityTag/...) would check whether the internal
> data has been already initialized.

It makes it easier for the developer because they control the
application thread, as opposed to the runtime controlling the
application thread (e.g. compare SAX to StAX).


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    Paul Sandoz