On 11 Apr 2010, at 06:49, Marius Bogoevici wrote:
On 2010-04-11, at 1:08 AM, Gavin King wrote:
> On Sat, Apr 10, 2010 at 11:18 PM, Marius Bogoevici
> <marius.bogoevici(a)gmail.com> wrote:
>> On 2010-04-11, at 12:07 AM, Gavin King wrote:
>>> It's the nature of @Dependent scope that two injection points never
>>> refer to the same instance, and that circularities are therefore an
>> Gavin, could you clarify that? From reading your comment, it seems like this use
>> implies unbound recursion: Foo injects Bar which in turns injects another
instance of Foo
>> (which is dependent on the first instance of Bar) which injects another instance
of Bar etc.
> Well, exactly. I mean, that's obvious from the definition of an
> @Dependent object, right?
> I mean, I don't quite follow what the source of doubt here is. Section
> 6.4 is *very* explicit on this.
Yeah, it's not like the definition is ambiguous, but it's still good to have it
summed up, I suppose - especially since it's relatively easy to create such a use
case (albeit inadvertently).
Incidentally, in the preamble of chapter 5 is said that : "The container is not
required to support circular chains of dependencies where every bean participating in the
chain has a pseudo-scope."
So the question would be what happens in the case of @Dependent - it seems the spec
should require a deployment error right away. Otherwise, implementors may choose to
'fix' this in a way that would violate the @Dependent definition. Also, it would
be good to do the same if other pseudo-scopes are affected.
The source of doubt is as Marius says - this is quite an easy thing to code up in CDI, and
the spec doesn't say that this a definition error (which it is normally clear about)
and that if it's just allowed, the user can easily get a stack overflow.