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Thread: Table 2.4

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import-bot

Posts: 20,296
Registered: 12/6/03
Table 2.4
Posted: Jul 22, 2003 11:00 PM
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[Originally posted by talicea]

I just need a clarification: Table 2.4 text says both that persistence needs
to be fine-grained and that persistence should not be fine-grained.

Also, where's the ERRATA page?


import-bot

Posts: 20,296
Registered: 12/6/03
Re: Table 2.4
Posted: Jul 22, 2003 11:00 PM   in response to: import-bot in response to: import-bot
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[Originally posted by plinskey]

> I just need a clarification: Table 2.4 text says both that persistence needs
> to be fine-grained and that persistence should not be fine-grained.

Hmm, I guess we weren't as clear as we should have been.

The point of that table is to list the various services provided by the EJB
specification, and the granularity that those services are typically used at.
So, persistence is typically something that you want to use in a fine-grained
manner relative to the other three services listed (typically, you'll want to
perform many persistence operations in the course of a transaction, for
example). However, because the EJB specification couples these four services
together, you're left in an inconvenient position in which you end up paying a
penalty -- your fine-grained persistence needs end up causing undue overhead
and architectural compromises.

So, in short, you do want persistence to be fine-grained, but the EJB spec
doesn't allow separation of the different services (except when using EJB2
local interfaces to separate out remote access). Since the other services (the
ones that EJB was designed for in the first place) are coarse-grained in
nature, many of the compromises that are OK for coarse-grained services get
unnecessarily forced on the persistence problem.

-Patrick


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