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Groups > comp.lang.java.programmer > #9925
| From | Tom Anderson <twic@urchin.earth.li> |
|---|---|
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: toward null-safe cookie cutter Comparators |
| Date | 2011-11-13 17:59 +0000 |
| Organization | Stack Usenet News Service |
| Message-ID | <alpine.DEB.2.00.1111131750140.19917@urchin.earth.li> (permalink) |
| References | <hkuvb758inpkqmju7aeeln2nab28i0aue6@4ax.com> |
On Sun, 13 Nov 2011, Roedy Green wrote: > I don't know how many people still subscribe, but I posted over in > comp.lang.advocacy a request on your preferred way of writing null-safe > Comparators. Roedy means (a) comp.lang.java.advocacy, and (b) comparators for objects some of whose fields may be null (ie i don't think he's concerned with comparators where one of the arguments may be null). For those of you who are into Google Groups, the other thread is here: http://groups.google.com/group/comp.lang.java.advocacy/browse_thread/thread/83db33bcbd51905d# Approaches involving nested if-elses will be more efficient, but always strike me as rather awkward. > I have shown a number of possible snippets. Please let me know what you > think and see if you can come up with something better - fast, terse and > comprehensible. I personally rather like your third option: final String aSpecies = a.species == null ? "" : a.species; final String bSpecies = b.species == null ? "" : b.species; return aSpecies.compareTo( bSpecies ); Perhaps even pushing the duplicated denullification into a little method. Note that when the Elvis operator makes it into Java, you will be able to write: return (a.species ?: "").compareTo(b.species ?: ""); Should you so wish. I'm also happy to see: if (a.species == b.species) return 0; as a guard clause ahead of the main comparison, which catches, as you say, both the both-null and identical-objects cases. tom -- No man ever steps in the same river twice, for it's not the same river and he's not the same man. -- Heraclitus
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toward null-safe cookie cutter Comparators Roedy Green <see_website@mindprod.com.invalid> - 2011-11-13 09:17 -0800
Re: toward null-safe cookie cutter Comparators Tom Anderson <twic@urchin.earth.li> - 2011-11-13 17:59 +0000
Re: toward null-safe cookie cutter Comparators Roedy Green <see_website@mindprod.com.invalid> - 2011-11-14 10:28 -0800
Re: toward null-safe cookie cutter Comparators Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-11-14 10:55 -0800
Re: toward null-safe cookie cutter Comparators Roedy Green <see_website@mindprod.com.invalid> - 2011-11-15 09:04 -0800
Re: toward null-safe cookie cutter Comparators kensi <kensi_kensington@zoonoses.de> - 2011-11-16 12:50 -0500
Re: toward null-safe cookie cutter Comparators Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-11-16 13:47 -0800
Re: toward null-safe cookie cutter Comparators Gene Wirchenko <genew@ocis.net> - 2011-11-16 16:09 -0800
Re: toward null-safe cookie cutter Comparators Lew <lewbloch@gmail.com> - 2011-11-16 17:02 -0800
Re: toward null-safe cookie cutter Comparators Gene Wirchenko <genew@ocis.net> - 2011-11-16 17:31 -0800
Re: toward null-safe cookie cutter Comparators Martin Gregorie <martin@address-in-sig.invalid> - 2011-11-17 22:51 +0000
Re: toward null-safe cookie cutter Comparators Paul Cager <paul.cager@googlemail.com> - 2011-11-17 02:43 -0800
Re: toward null-safe cookie cutter Comparators Tim Slattery <Slattery_T@bls.gov> - 2011-11-17 08:57 -0500
Re: toward null-safe cookie cutter Comparators Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-11-18 16:05 -0800
Re: toward null-safe cookie cutter Comparators kensi <kensi_kensington@zoonoses.de> - 2011-11-17 21:21 -0500
Re: toward null-safe cookie cutter Comparators Wanja Gayk <brixomatic@yahoo.com> - 2011-11-20 13:29 +0100
Re: toward null-safe cookie cutter Comparators Lew <lewbloch@gmail.com> - 2011-11-20 08:23 -0800
Re: toward null-safe cookie cutter Comparators Brixomatic <wanja.gayk@googlemail.com> - 2011-11-21 04:39 -0800
Re: toward null-safe cookie cutter Comparators Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-11-21 11:25 -0800
Re: toward null-safe cookie cutter Comparators Arne Vajhøj <arne@vajhoej.dk> - 2011-11-25 21:44 -0500
Re: toward null-safe cookie cutter Comparators Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-11-26 15:34 -0800
Re: toward null-safe cookie cutter Comparators Lew <lewbloch@gmail.com> - 2011-11-21 14:20 -0800
Re: toward null-safe cookie cutter Comparators Gene Wirchenko <genew@ocis.net> - 2011-11-21 19:22 -0800
Re: toward null-safe cookie cutter Comparators Lew <lewbloch@gmail.com> - 2011-11-21 22:45 -0800
Re: toward null-safe cookie cutter Comparators Wanja Gayk <brixomatic@yahoo.com> - 2011-12-10 12:15 +0100
Re: toward null-safe cookie cutter Comparators ilAn <idonot@wantspam.net> - 2011-12-10 19:47 +0200
Re: toward null-safe cookie cutter Comparators Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-12-10 14:57 -0400
Re: toward null-safe cookie cutter Comparators ilAn <nosuch@email.com> - 2011-12-11 10:46 +0200
Re: toward null-safe cookie cutter Comparators Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-12-12 07:42 -0400
Re: toward null-safe cookie cutter Comparators ilAn <nosuch@email.com> - 2011-12-12 16:06 +0200
Re: toward null-safe cookie cutter Comparators "Qu0ll" <Qu0llSixFour@gmail.com> - 2011-12-13 02:01 +1100
Re: toward null-safe cookie cutter Comparators Wanja Gayk <brixomatic@yahoo.com> - 2011-12-17 12:30 +0100
Re: toward null-safe cookie cutter Comparators Wanja Gayk <brixomatic@yahoo.com> - 2011-12-17 12:30 +0100
Re: toward null-safe cookie cutter Comparators Roedy Green <see_website@mindprod.com.invalid> - 2011-11-22 19:47 -0800
Re: toward null-safe cookie cutter Comparators Lew <lewbloch@gmail.com> - 2011-11-16 14:02 -0800
Re: toward null-safe cookie cutter Comparators Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-11-17 08:42 +0000
Re: toward null-safe cookie cutter Comparators Nigel Wade <nmw-news@ion.le.ac.uk> - 2011-11-17 15:09 +0000
Re: toward null-safe cookie cutter Comparators kensi <kensi_kensington@zoonoses.de> - 2011-11-17 21:22 -0500
Re: toward null-safe cookie cutter Comparators spk <jhic@speak.invalid> - 2011-11-17 13:40 -0400
Re: toward null-safe cookie cutter Comparators Lew <lewbloch@gmail.com> - 2011-11-17 09:56 -0800
Re: toward null-safe cookie cutter Comparators spk <jhic@speak.invalid> - 2011-11-17 14:00 -0400
Re: toward null-safe cookie cutter Comparators Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-11-17 19:23 +0000
Re: toward null-safe cookie cutter Comparators spk <jhic@speak.invalid> - 2011-11-17 16:35 -0400
Re: toward null-safe cookie cutter Comparators Lew <lewbloch@gmail.com> - 2011-11-17 13:50 -0800
Re: toward null-safe cookie cutter Comparators spk <jhic@speak.invalid> - 2011-11-17 18:48 -0400
Re: toward null-safe cookie cutter Comparators thoolen <tholen01@gmail.com> - 2011-11-17 18:33 -0800
Re: toward null-safe cookie cutter Comparators Lew <lewbloch@gmail.com> - 2011-11-17 13:48 -0800
Re: toward null-safe cookie cutter Comparators "Joe Attardi" <jattard1@gmail.com> - 2011-11-18 12:20 +0100
Re: toward null-safe cookie cutter Comparators thoolen <th00len@th0lenbot.thorium> - 2011-11-18 15:21 -0500
Re: toward null-safe cookie cutter Comparators thoolen <tholen01@gmail.com> - 2011-11-17 18:31 -0800
Re: toward null-safe cookie cutter Comparators Wanja Gayk <brixomatic@yahoo.com> - 2011-11-20 13:14 +0100
Re: toward null-safe cookie cutter Comparators Lew <lewbloch@gmail.com> - 2011-11-20 08:29 -0800
Re: toward null-safe cookie cutter Comparators Brixomatic <wanja.gayk@googlemail.com> - 2011-11-21 04:03 -0800
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