Hi Vincent,
On 01/18/2010 05:41 PM, Vincent Massol wrote:
>
> 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.
I think it's not that bad that they'd throw, IMO it's a particular case the one
we have now where all serializations make sense and can be interpreted as valid
(in other words, having a factory that requires a format for the strings it
parses is only normal).
>
>> ii) all objects of class className in the document
>
> I don't think it's valid. What would wiki:Space.Page^className#property mean?
could mean, by extension, the list of all values for property for all objects
of
class className in the document.
Which means we'd need to define OBJECT_LIST and PROPERTY_VALUE_LIST or
something
as EntityTypes.
>
>> 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?
yes, because they are identified by their index.
>
> 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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