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Groups > comp.lang.java.programmer > #24756
| From | Arved Sandstrom <asandstrom2@eastlink.ca> |
|---|---|
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: Interface with implied Constructor |
| References | <krgpcp$pba$1@speranza.aioe.org> <925adeb1-65b5-4a50-86a8-4f04784f8da0@googlegroups.com> <kri3sj$lnl$1@speranza.aioe.org> <b4g0e8F35pjU1@mid.individual.net> |
| Message-ID | <Qo1Gt.8876$2C2.1824@fx04.iad> (permalink) |
| Organization | Public Usenet Newsgroup Access |
| Date | 2013-07-18 23:21 -0300 |
On 07/14/2013 01:03 PM, Robert Klemme wrote: > On 10.07.2013 00:46, Richard Maher wrote: >> On 7/9/2013 7:08 PM, Robert Klemme wrote: >>> Why do you want to do that? >> >> For me it's personal preference, but for some technical rationale: - >> >> If you don't provide sufficient information to the constructor: >> 1) You get half-baked objects >> 2) Every real (non-init()) method now has to check "Has init() run? Am I >> complete?" > > Using a constructor to initialize an object does not make it necessary > to do that via reflection. You can have the same functionality simpler > with a factory. > >> 3) If using setters, how do you enforce that they are called in the >> correct order? > > Either throw IllegalStateException or use a single method for > initialization right away. > >> Most importantly, Why the hell do you think Java (and all other OO >> languages) support arguments to constructors and overloading in the >> first place??? Do you think the authors have been wasting their time or >> providing redundant technology all these years? > > Hammers are useful tools - but I usually don't use them to fix a screw. > >> So let me ask you "Why do you want to use setters or an init() method?" > > I opted for the init() method OR factory method pattern. Both are type > safe because in both cases a method in an interface needs to be > implemented. Picking a constructor solely based on argument types has a > looser coupling between the contract and the implementation of it. An > interface makes that coupling explicit. > > Cheers > > robert > > I'll be honest, Robert, personally I consider the behaviour of an object - the kinds of things you could specify in an interface - to be what the *initialized* object can (should) do. I seriously dislike init() methods, not just in Java. Particularly if there is no sensible un-init()'ed object for the class. I just don't see any credible argument for them. Like Richard said, actually: "half-baked". Often the best way to properly initialize an object is to call a constructor with arguments. That's what they are for. And to be honest once again, a ctor *is* an implementation thing, IMO: it's not the business of an interface to dictate how an implementation will initialize objects that can support the interface contract. After all, how can an interface even possibly imagine what the internal state of an initialized object, hence what ctor args are required, is? No problem with factory methods, except they are for specific situations. And I think they also lean more towards implementation. AHS -- When a true genius appears, you can know him by this sign: that all the dunces are in a confederacy against him. -- Jonathan Swift
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Interface with implied Constructor Richard Maher <maher_rjSPAMLESS@hotmail.com> - 2013-07-09 18:41 +0800
Re: Interface with implied Constructor Robert Klemme <shortcutter@googlemail.com> - 2013-07-09 04:08 -0700
Re: Interface with implied Constructor Richard Maher <maher_rjSPAMLESS@hotmail.com> - 2013-07-10 06:46 +0800
Re: Interface with implied Constructor Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-07-09 21:08 -0400
Re: Interface with implied Constructor Kevin McMurtrie <mcmurtrie@pixelmemory.us> - 2013-07-11 19:11 -0700
Re: Interface with implied Constructor Robert Klemme <shortcutter@googlemail.com> - 2013-07-14 17:53 +0200
Re: Interface with implied Constructor Kevin McMurtrie <mcmurtrie@pixelmemory.us> - 2013-07-15 08:58 -0700
Re: Interface with implied Constructor Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2013-07-15 10:57 -0700
[OT] Re: Interface with implied Constructor Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-07-15 14:13 -0400
Re: [OT] Re: Interface with implied Constructor Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2013-07-15 12:58 -0700
Re: Interface with implied Constructor Robert Klemme <shortcutter@googlemail.com> - 2013-07-15 20:45 +0200
Re: Interface with implied Constructor Robert Klemme <shortcutter@googlemail.com> - 2013-07-14 18:03 +0200
Re: Interface with implied Constructor Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-07-18 23:21 -0300
Re: Interface with implied Constructor Gene Wirchenko <genew@telus.net> - 2013-07-19 12:38 -0700
Re: Interface with implied Constructor Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-07-19 17:56 -0300
Re: Interface with implied Constructor Gene Wirchenko <genew@telus.net> - 2013-07-22 12:39 -0700
Re: Interface with implied Constructor Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-07-22 16:02 -0400
Re: Interface with implied Constructor Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-07-22 18:08 -0300
Re: Interface with implied Constructor Gene Wirchenko <genew@telus.net> - 2013-07-23 14:32 -0700
Re: Interface with implied Constructor Jim Gibson <jimsgibson@gmail.com> - 2013-07-23 14:43 -0700
Re: Interface with implied Constructor Gene Wirchenko <genew@telus.net> - 2013-07-24 13:27 -0700
Re: Interface with implied Constructor Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-07-24 18:20 -0300
Re: Interface with implied Constructor Robert Klemme <shortcutter@googlemail.com> - 2013-07-26 00:03 +0200
Re: Interface with implied Constructor Martin Gregorie <martin@address-in-sig.invalid> - 2013-07-24 21:18 +0000
Re: Interface with implied Constructor Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-07-24 17:42 -0400
Re: Interface with implied Constructor Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-07-23 18:19 -0400
Re: Interface with implied Constructor Gene Wirchenko <genew@telus.net> - 2013-07-24 13:31 -0700
Re: Interface with implied Constructor Steven Simpson <ss@domain.invalid> - 2013-07-27 04:06 +0100
Re: Interface with implied Constructor Martin Gregorie <martin@address-in-sig.invalid> - 2013-07-19 21:21 +0000
Re: Interface with implied Constructor Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-07-19 18:56 -0300
Re: Interface with implied Constructor Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-07-19 18:10 -0400
Re: Interface with implied Constructor Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-07-19 20:46 -0300
Re: Interface with implied Constructor Richard Maher <maher_rjSPAMLESS@hotmail.com> - 2013-07-20 12:42 +0800
Re: Interface with implied Constructor Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-07-20 09:08 -0300
Re: Interface with implied Constructor Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-07-20 09:08 -0400
Re: Interface with implied Constructor Kevin McMurtrie <mcmurtrie@pixelmemory.us> - 2013-07-19 19:20 -0700
Re: Interface with implied Constructor markspace <markspace@nospam.nospam> - 2013-07-19 20:11 -0700
Re: Interface with implied Constructor Richard Maher <maher_rjSPAMLESS@hotmail.com> - 2013-07-20 12:26 +0800
Re: Interface with implied Constructor Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-07-20 09:38 -0300
Re: Interface with implied Constructor Robert Klemme <shortcutter@googlemail.com> - 2013-07-20 19:46 +0200
Re: Interface with implied Constructor Martin Gregorie <martin@address-in-sig.invalid> - 2013-07-20 19:12 +0000
Re: Interface with implied Constructor Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-07-20 17:12 -0400
Re: Interface with implied Constructor Martin Gregorie <martin@address-in-sig.invalid> - 2013-07-20 21:18 +0000
Re: Interface with implied Constructor Robert Klemme <shortcutter@googlemail.com> - 2013-07-21 12:13 +0200
Re: Interface with implied Constructor Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-07-21 16:18 -0300
Re: Interface with implied Constructor markspace <markspace@nospam.nospam> - 2013-07-21 13:45 -0700
Re: Interface with implied Constructor Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-07-21 16:58 -0400
Re: Interface with implied Constructor Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-07-21 21:19 -0300
Re: Interface with implied Constructor Robert Klemme <shortcutter@googlemail.com> - 2013-07-20 20:09 +0200
Re: Interface with implied Constructor Robert Klemme <shortcutter@googlemail.com> - 2013-07-20 20:21 +0200
Re: Interface with implied Constructor Joerg Meier <joergmmeier@arcor.de> - 2013-07-20 23:17 +0200
Re: Interface with implied Constructor Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-07-20 17:32 -0400
Re: Interface with implied Constructor Joerg Meier <joergmmeier@arcor.de> - 2013-07-21 00:10 +0200
Re: Interface with implied Constructor Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-07-21 17:53 -0300
Re: Interface with implied Constructor markspace <markspace@nospam.nospam> - 2013-07-09 18:13 -0700
Re: Interface with implied Constructor Richard Maher <maher_rjSPAMLESS@hotmail.com> - 2013-07-10 18:03 +0800
Re: Interface with implied Constructor markspace <markspace@nospam.nospam> - 2013-07-10 08:41 -0700
Re: Interface with implied Constructor Richard Maher <maher_rjSPAMLESS@hotmail.com> - 2013-07-11 06:53 +0800
Re: Interface with implied Constructor Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2013-07-09 21:41 -0700
Re: Interface with implied Constructor Richard Maher <maher_rjSPAMLESS@hotmail.com> - 2013-07-10 17:55 +0800
Re: Interface with implied Constructor Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2013-07-10 14:52 -0700
Re: Interface with implied Constructor Roedy Green <see_website@mindprod.com.invalid> - 2013-07-10 16:02 -0700
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