Re: persistence / object backend to file / serialization

Tom Anderson <>
Mon, 8 Feb 2010 14:36:08 +0000
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On Sun, 7 Feb 2010, luc peuvrier wrote:

On 1 f?v, 19:30, luc peuvrier <> wrote:

On Feb 1, 1:30?am, Tom Anderson <> wrote:

On Sun, 31 Jan 2010, luc peuvrier wrote:
can be see as a:
- an "intelligent" serialization: write only changes, read only object
- manage more object than memory can contains
- an alternate persistence solution to relationnal database

So you've basically reinvented JDO? That's cool, i always liked JDO.

I do not think reinvented JDO. If you like JDO and well know it I will
be happy you compare theJOAFIPand JDO facade.

Lew insist I answer to you and not ask to you to compare.
Joafip is not same as JDO. I am not a JDO expert, but I had a look on
its description. About joafip:

- do not make able to choose storage form, only in a file

True, but that fits with JDO. Different JDO implementations use different
kinds of storage - some use a RDBMS, some use files, some use something
else. Joafip is similar to a JDO implementation that only uses files.

- do not have request language, not an pool of object, but an object
graph storage.

True. JDO provides navigation as well - the examples you give for Joafip
could also be done with JDO (or JPA). But JDO and JPA also provide their
own languages. As it happens, IMHO most of the use of a persistence system
is navigational; you have a few well-known root objects (the ones bound to
a name in the session in Joafip), and then you navigate from there. Having
a query language is a nice extra, and in some cases is essential, but for
bread-and-butter storage applications, not required. Although of course,
once you have a query language, you do tend to use it more.

- persist any data-model ( some constraints )

True. Same is true of JDO and JPA. With JPA, you need to add annotations
(or a configuration file) to say which attributes to persist, but with
JDO, you don't. With JDO, you need to apply bytecode enhancement, which
can be done at build-time, or at classingloading time, via an agent, which
i believe Joafip can also do.

So you see, Joafip looks very similar to a JDO implementation. I should
reiterate that this is a *good* thing, because JDO is a good standard!


NTK now entirely filled with google links -- NTK

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