[cdi-dev] calling 'equals' on a proxy?

[Rick Hightower]

I would argue (and probably lose) that something that worked in 99% of cases
as expected would be better than something that never does.

I will reread Stuarts arguments, but it seems to me that we can specify how
equals works with client proxies.

On Tue, Oct 18, 2011 at 1:56 PM, Pete Muir <pmuir at redhat.com> wrote:

>
> On 18 Oct 2011, at 21:42, Rick Hightower wrote:
>
> > Currently the docs say this.... 5.4.2.
> >
> > •Behavior of all methods declared by java.lang.Object, except for
> toString(), is undefined for a client proxy
> > •Portable applications should not invoke any method declared by
> java.lang.Object, except for toString(), on a client proxy
> >
> > I so don't agree with what is in the spec. now on this subject.
> > (Realizing that it is a work in progress...)
>
> Not really, this is unchanged since 1.0. We don't currently have plans to
> change this.
>
> >
> > I think we should change this and call the underlying implementation for
> these methods.
> > Also equals and hashCode should work by unpacking and comparing the
> contextual instance.
>
> Please take a look at Stuart's follow up to Mark's email, he has
> investigated the options thoroughly, and found there is no solution that can
> correctly obey the rules for equals. For this reason it's better to keep it
> unspecified, as it warns people not to rely on this behavior.
>
> >
> > Off topic....
> >
> > It would be nice if there was a utility API that implementations had to
> implement that had these methods
> >
> >
> > isProxy (lets you know if an object is a client proxy)
> > getUnproxiedVersion (gives you the underlying unproxied version of the
> object)
> >
> >
> > (It may exist already.)
>
> I don't believe there is, so file a CDI issue and we can discuss / add it.
> It should be relatively trivial (require any client proxy to implement an
> interface e.g. ClientProxy and provide a method on getUnderlying() or
> similar).
>
> >
> >
> > On Tue, Oct 18, 2011 at 10:17 AM, Mark Struberg <struberg at yahoo.de>
> wrote:
> > Hi folks!
> >
> > There is a problem still in the chain which is a bit more trickier. It's
> about equals() on contextual references.
> >
> > If the 'other' instance which gets compared with is a proxy as well, then
> we would first need to 'unpack' it and pass the underlying contextual
> instance into the comparison implementation. Otherwise accessing private
> fields from the 'other' will actually only hit the proxy, and not the 'real'
> target.
> >
> > But otherwise it should work fine.
> >
> >
> > Wdyt?
> >
> > 1.) Should we specify this?
>
> See Stuart's response, I would be very leery of requiring behavior which
> broke the fundamental contract of equals(). If we can't fully support the
> correct behavior, it's better to leave it unportable.
>
> >
> > 2.) What is the expected behaviour?
> >
> > 3.) Do we like to specify equals() for beans at all?
> > 4.) Is there some established behaviour in other frameworks which heavily
> uses proxies?
>
> Not AFAIK. We played around for ages with this in Seam and Weld, and have
> something that gives you 99% correct behavior, but there are still edge
> cases.
>
> > 5.) Should we at least specify that 'non portable behaviour results'?
>
> We do, see Rick's reference above.
>
> >
> >
> > LieGrue,
> > strub
> >
> >
> >
> > ----- Original Message -----
> > > From: Pete Muir <pmuir at redhat.com>
> > > To: Mark Struberg <struberg at yahoo.de>
> > > Cc: cdi-dev at lists.jboss.org; Stuart Douglas <sdouglas at redhat.com>
> > > Sent: Monday, March 14, 2011 12:52 PM
> > > Subject: Re: [cdi-dev] calling 'equals' on a proxy?
> > >
> > > Stuart, you had this one worked out right? I believe the spec says the
> behaviour
> > > is unspecified.
> > >
> > > On 7 Mar 2011, at 15:52, Mark Struberg wrote:
> > >
> > >>  Hi Pete, others!
> > >>
> > >>  Do you remember our discussion about what should happen if equals()
> gets
> > > called on a proxy?
> > >>
> > >>  Should it route to the equals method of the currently proxied
> instance?
> > >>
> > >>  LieGrue,
> > >>  strub
> > >>
> > >>
> > >>
> > >>  _______________________________________________
> > >>  cdi-dev mailing list
> > >>  cdi-dev at lists.jboss.org
> > >>  https://lists.jboss.org/mailman/listinfo/cdi-dev
> > >
> >
> >
> > _______________________________________________
> > cdi-dev mailing list
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> > https://lists.jboss.org/mailman/listinfo/cdi-dev
> >
> >
> >
> > --
> > Rick Hightower
> > (415) 968-9037
> > Profile
> >
>
>


-- 
*Rick Hightower*
(415) 968-9037
Profile <http://www.google.com/profiles/RichardHightower>
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