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From: Felix Meschberger <fmeschbe@adobe.com>
To: "dev@jackrabbit.apache.org" <dev@jackrabbit.apache.org>
Date: Fri, 15 Mar 2013 13:59:29 +0000
Subject: Re: Getting a value by its data identifier
Thread-Topic: Getting a value by its data identifier
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Hi

I created https://issues.apache.org/jira/browse/JCR-3534 with a patch imple=
menting the proposed method along with a unit test validating round trippin=
g.

Regards
Felix

Am 12.03.2013 um 12:32 schrieb Felix Meschberger:

> Hi all
>=20
> we have a couple of use cases, where we would like to leverage the global=
 data store to prevent sending around and copying around large binary data =
unnecessarily: We have two separate Jackrabbit instances configured to use =
the same DataStore (for the sake of this discussion assume we have the prob=
lems of concurrent access and garbage collection under control). When sendi=
ng content from one instance to the other instance we don't want to send po=
tentially large binary data (e.g. video files) if not needed.
>=20
> The idea is for the sender to just send the content identity from Jackrab=
bitValue.getContentIdentity(). The receiver would then check whether the su=
ch content already exists and would reuse if so:
>=20
>  String ci =3D contentIdentity_from_sender;
>  try {
>    Value v =3D session.getValueByContentIdentity(ci);
>    Property p =3D targetNode.setProperty(propName, v);
>  } catch (ItemNotFoundException ie) {
>    // unknown or invalid content Identity
>  } catch (RepositoryException re) {
>    // some other exception
>  }
>=20
> Thus the proposed JackrabbitSession.getValueByContentIdentity(String) met=
hod would allow for round tripping the JackrabbitValue.getContentIdentity()=
 preventing superfluous binary data copying and moving.
>=20
> Questions:
>=20
> (a) Would such a method technically be possible (preventing actual large =
binary data copy !) ?
> (b) Would a patch be accepted ?
> (c) Can we and if yes, how can we control access ?
> (c) What else ?
>=20
> Regards
> Felix
>=20
> --
> Felix Meschberger | Principal Scientist | Adobe
>=20
>=20
>=20
>=20
>=20
>=20
>=20


--
Felix Meschberger | Principal Scientist | Adobe