Re: [infinispan-dev] Avoid Collections.emptySet() / emptyMap() / emptyList

Also be aware that JBMAR has specific optimizations for the JDK empty collections - they are represented by a single byte in the stream.

On 10/19/2012 11:28 AM, Dan Berindei wrote: > Galder, what JDK are you using? OpenJDK 1.7 uses > EmptyIterator.EMPTY_ITERATOR since 2007: > > http://hg.openjdk.java.net/jdk7/jdk7/jdk/annotate/37a05a11f281/src/share/... > > I don't have JDK 1.6 sources on hand to check, but I don't think it's > worth optimizing for such an old version anyway. > > Cheers > Dan > > > On Fri, Oct 19, 2012 at 5:50 PM, Vladimir Blagojevic > <vblagoje(a)redhat.com <mailto:vblagoje@redhat.com>> wrote: > > Cool! Did not know about this! Is this original idea or others are > already doing this? > On 12-10-19 8:31 AM, Galder Zamarreño wrote: >> Hi all, >> >> Re: > https://github.com/galderz/infinispan/commit/0609207d13216de81d77ff51dc20... >> >> Please avoid using these JDK methods where possible. I've created > alternative versions in InfinispanCollections util class that > provide a better implementation. >> >> The problem with the JDK versions is that even if these > collections are immutable, if you wanna iterate them (i.e. for(X : > emptySet) ), they'll create a brand new Iterator every time they're > looped, and that generates useless garbage. >> >> The InfinispanCollections versions of emptyX will return a > constant singleton iterator which avoids this problem, and avoids > the need for client code to check if the collection is empty before > looping. >> >> Cheers, >> -- >> Galder Zamarreño >> galder(a)redhat.com <mailto:galder@redhat.com> >> twitter.com/galderz <http://twitter.com/galderz> >> >> Project Lead, Escalante >> http://escalante.io >> >> Engineer, Infinispan >> http://infinispan.org >> >> >> _______________________________________________ >> infinispan-dev mailing list >> infinispan-dev(a)lists.jboss.org > <mailto:infinispan-dev@lists.jboss.org> >> https://lists.jboss.org/mailman/listinfo/infinispan-dev > > _______________________________________________ > infinispan-dev mailing list > infinispan-dev(a)lists.jboss.org <mailto:infinispan-dev@lists.jboss.org> > https://lists.jboss.org/mailman/listinfo/infinispan-dev > > > > > _______________________________________________ > infinispan-dev mailing list > infinispan-dev(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/infinispan-dev > -- - DML _______________________________________________ infinispan-dev mailing list infinispan-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/infinispan-dev