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
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