18 Jan
2010
18 Jan
'10
4:41 p.m.
On Jan 18, 2010, at 3:54 PM, Anca Luca wrote:
Hi devs,
to resume, and try to converge to an implementable version, I propose:
1/ adding only OBJECT and PROPERTY EntityTypes for the moment, referring to an
object instance and a property instance in a document (a property ref would have
an object as a parent which would have a document reference as a parent), and
limiting the implementation to references to properties of object instances
(leaving aside type definitions ftm).
here's my +1 for this.
We need to define the names we're going to use first so I'm putting a -1 to block
till we define them.
2/ using a serialization of the form
wiki:Space.Page^className[objectnumber]#property and
a) using indexed ('multivalued') references, adding an additional
IndexedEntityReference class, to which API caller would have to cast.
ObjectReference would be such an IndexedEntityReference and provide object
related helper functions.
b) className[objectnumber] is used as an 'object name', it would be the name of
the object reference, and it would be the caller of the generic API that would
have to parse & serialize this kind of strings to actually extract classname and
object index. However, this would again be all hidden behind the ObjectReference
API.
I'm 0.5 and 0.5 between the two, any would suit my purpose.
-1 for b) since
- we would need to recode resolvers, serializers and a data object to hold the data,
basically redoing everything I've done for References.
- it would make a not nice API
+0 for a)
An additional question is what would
wiki:Space.Page^className (and
wiki:Space.Page^className#property) mean:
i) nothing, we consider it as invalid reference, we'll fix that later, we keep
it simple ftm
my +1 goes for this
-0
Right now all our resolvers never throw an exception. I'd like to keep them like this
as much as possible.
ii) all objects of class className in the document
I don't think it's valid. What would wiki:Space.Page^className#property mean?
iii) first object of that class in the document (as
XWikiDocument#getObject(className) does)
iv) a shortcut for wiki:Space.Page^className[0]
(which, note, does not
necessarily mean the first object in that document, since indexing of objs in a
document is not recomputed when objects are deleted).
What is the reason? So that object names don't move when objects are added/removed?
I don't know enough but +0 for iii) or iv).
Thanks
-Vincent
WDYT?
Thanks,
Anca
On 01/13/2010 02:42 PM, Anca Luca wrote:
> Hi devs,
>
> Short story:
> 1/ add the CLASS, OBJECT, PROPERTY EntityTypes in the model
>
> +1
>
> 2/ serialization for referencing a property of an object
> a) wiki:Space.Page^className[objectNumber]#property
> b) wiki:Space.Page^className#objectNumber$property
> +0.75 for b)
>
> Long story:
>
> 1/ I would need to extend the EntityReference to be able to target a
> property in an object in a document.
> For this, I will need to add
>
> /**
> * Represents a Class Entity
> */
> CLASS,
>
> /**
> * Represents an Object Entity.
> */
> OBJECT,
>
> /**
> * Represents a Property Entity
> */
> PROPERTY,
>
> in the EntityType. Although I would prefer an extensible framework that
> would allow to extend the possible entity types without changing an enum
> in the platform (for any API user to be able to define its own
> references), I think this is fairly extensible (these are key concepts
> in the xwiki model and I don't think they would be changed that soon,
> and their interpretation is flexible, they could be combined with any
> parent to generate either references to class definitions or instances).
> here's my +1 for this.
>
> 2/ I would also need a 'standard' string serialization for these. Now,
> there's also the option to do it in my own module (annotations) because
> only I need it ftm, but I prefer to have a platform wide approach. Opinions?
> There are 2 choices, with a potentially different combination of separators:
>
> a/ wiki:Space.Page^className[objectNumber]#property
>
> pros: it's a suggestive way to access objects by number ([] is the
> standard syntax for array indexed access and the objects are accessed by
> index), [] is supported by JCR so maybe we should support it too
> cons: [] is somewhat inconsistent with all other separators which are
> just one separator, to the left (right) of the entity, harder to
> implement the [] separators on the current framework
>
> b/ wiki:Space.Page^className#objectNumber$property
>
> pros: inline with the separator usage we already have (and easier to
> implement for this reason), could be easier refactored to contain an
> object name instead of the number
> cons: $ separator can collide with velocity syntax (can potentially
> cause trouble when used in velocity -- an alternative could be the pipe
> |), could be harder to drop the object number part of the reference to
> refer a property in a class (if wanted, in the future)
>
> I have no other argument between a) and b) but the implementation speed
> one, so I'd go for a b)-like approach, in the spirit of the current
> separators.
>
> WDYT?
>
> Thanks,
> Anca