Re: [cdi-dev] Mutable annotation literals

> Except that the hash code rules for annotations aren't that easy to follow. Exactly! That was the reason why I made the sample with the super.hashCode() code. For any 'constant' AnnotationLiteral you just additionally add a few lines which 'caches' the hashCode. public class TransactionScopedLiteral extends AnnotationLiteral<TransactionScoped> implements TransactionScoped { private Integer hashCode = null; public int hashCode() { if (hashCode == null) { hashCode = super.hashCode(); } return hashCode; } ... } we could of course also add a new additional constructor with a 'boolean constant' parameter LieGrue, strub ----- Original Message ----- > From: Pete Muir <pmuir(a)redhat.com&gt; > To: Mark Struberg <struberg(a)yahoo.de&gt; > Cc: cdi-dev <cdi-dev(a)lists.jboss.org&gt; > Sent: Thursday, August 16, 2012 3:01 PM > Subject: Re: [cdi-dev] Mutable annotation literals > > > On 16 Aug 2012, at 13:58, Mark Struberg wrote: > >> The problem is an AnnotationLiteral could theoretically be mutable as well. > Thus the AnnotationLiteral class must not make such assumptions imo. > > Agreed. > >> >> >> I the case of an empty value-methods list we could btw also improve the > equals method. > > Yes. > >> >> In the case where you have value-methods, you already need to implement the > interface manually. It would be no problem to just add the 2 lines for caching > the hashCode in case the values do not change. > > Except that the hash code rules for annotations aren't that easy to follow. > >> >> >> LieGrue, >> strub >> >> >> >> ----- Original Message ----- >>> From: Pete Muir <pmuir(a)redhat.com&gt; >>> To: Mark Struberg <struberg(a)yahoo.de&gt; >>> Cc: cdi-dev <cdi-dev(a)lists.jboss.org&gt; >>> Sent: Thursday, August 16, 2012 2:20 PM >>> Subject: Re: [cdi-dev] Mutable annotation literals >>> >>> I guess what Marko/I am proposing is that we provide a utility for the > common >>> case of an immutable annotation literal with member values... >>> >>> On 16 Aug 2012, at 13:18, Mark Struberg wrote: >>> >>>> Imo we don't need to cache the hashCode in the > AnnotationLiteral >>> itself. We just need to cache if there are value methods or not. If > not, then we >>> can immediately return 0. If there are value methods present, then you > need to >>> extend the AnnotationLiteral class anyway and can add an own hashCode > which >>> delegates to super.hashCode() and caches the result if the values will > not be >>> changed. >>>> >>>> LieGrue, >>>> strub >>>> >>>> >>>> >>>> >>>> ----- Original Message ----- >>>>> From: Pete Muir <pmuir(a)redhat.com&gt; >>>>> To: cdi-dev <cdi-dev(a)lists.jboss.org&gt; >>>>> Cc: >>>>> Sent: Thursday, August 16, 2012 1:43 PM >>>>> Subject: [cdi-dev] Mutable annotation literals >>>>> >>>>> All >>>>> >>>>> Marko has added caching for the hashcode value on > AnnotationLiteral, >>> which is >>>>> based on the premise that an AnnotationLiteral is not mutable. >>>>> >>>>> >>> > https://github.com/luksa/cdi/commit/f3c200fcdf8ca8681c194c921567aedcce375102 >>>>> >>>>> This is a reasonable thing to require (as real annotations are > normally >>> >>>>> immutable!) and a very good optimisation, however it is not > backwards >>>>> compatible, as we have not previously required > AnnotationLiteral to be >>>>> immutable. >>>>> >>>>> An alternative option is to introduce the > ImmutableAnnotationLiteral >>> subclass, >>>>> which would require any concrete instances to be immutable and > could >>> use this >>>>> optimisation. We could "deprecate" AnnotationLiteral > (as >>> described in >>>>> java.net/projects/javaee-spec/pages/CompatibilityRequirements). >>>>> >>>>> Note that regardless, we can apply the minor optimisation > suggested by >>> Mark, >>>>> that we return 0 if the annotation has no members. >>>>> >>>>> Pete >>>>> _______________________________________________ >>>>> cdi-dev mailing list >>>>> cdi-dev(a)lists.jboss.org >>>>> https://lists.jboss.org/mailman/listinfo/cdi-dev >>>>> >>> > _______________________________________________ cdi-dev mailing list cdi-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/cdi-dev