Groups | Search | Server Info | Keyboard shortcuts | Login | Register
Groups > comp.lang.java.programmer > #3630
| From | Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> |
|---|---|
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: "Program to an interface" - When to break a design pattern |
| Date | 2011-05-06 02:28 +0200 |
| Organization | A noiseless patient Spider |
| Message-ID | <ipvfcm$o6a$1@dont-email.me> (permalink) |
| References | (3 earlier) <2poc3gq3p2.fsf@shell.xmission.com> <ipv2ej$ka6$1@dont-email.me> <2pk4e4q2sq.fsf@shell.xmission.com> <ipv6q5$vq4$1@dont-email.me> <2py62kohyi.fsf@shell.xmission.com> |
On 06/05/2011 01:17, Jim Janney allegedly wrote: > Daniele Futtorovic<da.futt.news@laposte-dot-net.invalid> writes: > >> On 05/05/2011 23:02, Jim Janney allegedly wrote: >>> Daniele Futtorovic<da.futt.news@laposte-dot-net.invalid> writes: >>> >>>> On 05/05/2011 22:42, Jim Janney allegedly wrote: >>>>> Daniele Futtorovic<da.futt.news@laposte-dot-net.invalid> writes: >>>>> >>>>>> On 05/05/2011 22:14, Jim Janney allegedly wrote: >>>>>>> The point of programming to the interface is to make it easier to >>>>>>> substitute a different implementation, which implies that any >>>>>>> reasonable implementation can be used. If this is not true, if the >>>>>>> code that uses the object relies on behavior only found in one >>>>>>> implementation, then there is no benefit to using the interface, and >>>>>>> you make it more inviting for someone to break things later on. So >>>>>>> in this case, no, programming to the interface would be the wrong >>>>>>> thing to do. The point of design principles is to make you think >>>>>>> before you break them :-) >>>>>> >>>>>> Entirely disagreed. The code shown did not contain any justification for >>>>>> breaking the pattern in question, and on the opposite, it contained all >>>>>> the reasons to think more about encapsulation, which is the true >>>>>> underlying rationale for coding to interfaces -- not polymorphism per se. >>>>> >>>>> The justification is not in the code shown, but in the accompanying >>>>> remark "I need the map to retain the insertion order." There's no >>>>> interface in the JRE that promises this, and only one class that >>>>> provides it, which makes encapsulation, shall we say, difficult. >>>> >>>> That's not the point! Yes, you need a LinkedHashMap to retain >>>> insertion order in a Map. But retaining insertion order is >>>> relevant... only when inserting. >>> >>> Think a minute. When does retaining insertion order actually matter? >>> When you build the map, or some time later when you iterate over it? >>> Hint: if you never iterate over it, the order doesn't matter at all. >> >> I don't need a full minute to see that this is even further beside the >> point. > > In the absence of more code, we have to take the original poster's > word that callers to getSortedMap() actually depend on the insertion > order. But there's no reason to suppose they don't: the effects are in > no way limited to map creation. > Actually, he doesn't exactly say that /callers/ depend on insertion order. He said: > where I'm creating sortedMap above, I need the map to > retain the insertion order I interpret "where I'm creating the map" as being in the getSortedMap() method. Perhaps he really meant the code that calls getSortedMap(), in which case this method would be a factory method. But I assumed it wasn't, because of the getter-like name, and also because of what he said further below. If it were a factory method -- then yes, by all means. If it's a factory method that creates a map retaining insertion order, then its return type should be LinkedHashMap. But that's actually the only exception I can think of. I cannot fathom any other, normal OO case where LinkedHashMap would make sense as the type of a parameter to, or the return type of any method. -- DF. An escaped convict once said to me: "Alcatraz is the place to be"
Back to comp.lang.java.programmer | Previous | Next — Previous in thread | Next in thread | Find similar
"Program to an interface" - When to break a design pattern Zapanaz <http://joecosby.com/code/mail.pl@foo.com> - 2011-05-05 12:21 -0700
Re: "Program to an interface" - When to break a design pattern Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-05-05 15:43 -0400
Re: "Program to an interface" - When to break a design pattern Lew <noone@lewscanon.com> - 2011-05-05 17:19 -0400
Re: "Program to an interface" - When to break a design pattern Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-05-05 21:47 +0200
Re: "Program to an interface" - When to break a design pattern Jim Janney <jjanney@shell.xmission.com> - 2011-05-05 14:14 -0600
Re: "Program to an interface" - When to break a design pattern Zapanaz <http://joecosby.com/code/mail.pl@foo.com> - 2011-05-05 13:26 -0700
Re: "Program to an interface" - When to break a design pattern Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-05-05 22:27 +0200
Re: "Program to an interface" - When to break a design pattern Jim Janney <jjanney@shell.xmission.com> - 2011-05-05 14:42 -0600
Re: "Program to an interface" - When to break a design pattern Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-05-05 22:48 +0200
Re: "Program to an interface" - When to break a design pattern Jim Janney <jjanney@shell.xmission.com> - 2011-05-05 15:02 -0600
Re: "Program to an interface" - When to break a design pattern Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-05-06 00:02 +0200
Re: "Program to an interface" - When to break a design pattern Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-05-05 19:49 -0300
Re: "Program to an interface" - When to break a design pattern Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-05-06 02:28 +0200
Re: "Program to an interface" - When to break a design pattern Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-05-06 07:24 -0300
Re: "Program to an interface" - When to break a design pattern Patricia Shanahan <pats@acm.org> - 2011-05-06 07:03 -0700
Re: "Program to an interface" - When to break a design pattern Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-05-06 17:30 -0300
Re: "Program to an interface" - When to break a design pattern Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-05-06 18:56 +0200
Re: "Program to an interface" - When to break a design pattern Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-05-06 17:50 -0300
Re: "Program to an interface" - When to break a design pattern Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-05-06 23:37 +0200
Re: "Program to an interface" - When to break a design pattern Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-05-06 19:43 -0300
Re: "Program to an interface" - When to break a design pattern Jim Janney <jjanney@shell.xmission.com> - 2011-05-05 17:17 -0600
Re: "Program to an interface" - When to break a design pattern Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-05-06 02:28 +0200
Re: "Program to an interface" - When to break a design pattern Zapanaz <http://joecosby.com/code/mail.pl@foo.com> - 2011-05-05 23:25 -0700
Re: "Program to an interface" - When to break a design pattern Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-05-06 18:25 +0200
Re: "Program to an interface" - When to break a design pattern Zapanaz <http://joecosby.com/code/mail.pl@foo.com> - 2011-05-07 16:26 -0700
Re: "Program to an interface" - When to break a design pattern Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-05-08 03:28 +0200
Re: "Program to an interface" - When to break a design pattern Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-05-08 00:05 -0300
Re: "Program to an interface" - When to break a design pattern Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-05-08 16:15 +0200
Re: "Program to an interface" - When to break a design pattern Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-05-08 14:20 -0300
Re: "Program to an interface" - When to break a design pattern Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-05-08 19:48 +0200
Re: "Program to an interface" - When to break a design pattern markspace <-@.> - 2011-05-10 07:36 -0700
Re: "Program to an interface" - When to break a design pattern Jim Janney <jjanney@shell.xmission.com> - 2011-05-10 13:04 -0600
Re: "Program to an interface" - When to break a design pattern Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-05-10 21:31 +0200
Re: "Program to an interface" - When to break a design pattern Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-05-10 20:01 -0300
Re: "Program to an interface" - When to break a design pattern Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-05-11 19:14 +0200
Re: "Program to an interface" - When to break a design pattern Patricia Shanahan <pats@acm.org> - 2011-05-11 10:41 -0700
Re: "Program to an interface" - When to break a design pattern Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-05-11 19:55 +0200
Re: "Program to an interface" - When to break a design pattern Lew <noone@lewscanon.com> - 2011-05-11 16:42 -0400
Re: "Program to an interface" - When to break a design pattern Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-05-11 23:34 +0200
Re: "Program to an interface" - When to break a design pattern "John B. Matthews" <nospam@nospam.invalid> - 2011-05-12 00:51 -0400
Re: "Program to an interface" - When to break a design pattern Lew <noone@lewscanon.com> - 2011-05-12 00:58 -0400
Re: "Program to an interface" - When to break a design pattern Tom Anderson <twic@urchin.earth.li> - 2011-05-12 20:08 +0100
Re: "Program to an interface" - When to break a design pattern Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-05-15 13:25 -0300
Re: "Program to an interface" - When to break a design pattern Lew <noone@lewscanon.com> - 2011-05-05 17:24 -0400
Re: "Program to an interface" - When to break a design pattern Jim Janney <jjanney@shell.xmission.com> - 2011-05-05 16:00 -0600
Re: "Program to an interface" - When to break a design pattern Jukka Lahtinen <jtfjdehf@hotmail.com.invalid> - 2011-05-06 15:01 +0300
Re: "Program to an interface" - When to break a design pattern Lew <noone@lewscanon.com> - 2011-05-06 12:17 -0400
Re: "Program to an interface" - When to break a design pattern Zapanaz <http://joecosby.com/code/mail.pl@foo.com> - 2011-05-07 16:28 -0700
Re: "Program to an interface" - When to break a design pattern Lew <noone@lewscanon.com> - 2011-05-05 17:21 -0400
Re: "Program to an interface" - When to break a design pattern Jim Janney <jjanney@shell.xmission.com> - 2011-05-05 15:58 -0600
Re: "Program to an interface" - When to break a design pattern Lew <noone@lewscanon.com> - 2011-05-05 18:18 -0400
Re: "Program to an interface" - When to break a design pattern Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-05-05 19:20 -0300
Re: "Program to an interface" - When to break a design pattern Lew <noone@lewscanon.com> - 2011-05-05 18:23 -0400
Re: "Program to an interface" - When to break a design pattern Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-05-05 20:17 -0300
Re: "Program to an interface" - When to break a design pattern Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-05-05 18:26 -0300
Re: "Program to an interface" - When to break a design pattern Steven Simpson <ss@domain.invalid> - 2011-05-05 22:57 +0100
Re: "Program to an interface" - When to break a design pattern Tom Anderson <twic@urchin.earth.li> - 2011-05-05 23:29 +0100
Re: "Program to an interface" - When to break a design pattern Steven Simpson <ss@domain.invalid> - 2011-05-06 13:30 +0100
Re: "Program to an interface" - When to break a design pattern Lew <noone@lewscanon.com> - 2011-05-06 12:19 -0400
Re: "Program to an interface" - When to break a design pattern Jim Janney <jjanney@shell.xmission.com> - 2011-05-05 16:41 -0600
Re: "Program to an interface" - When to break a design pattern Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-05-05 20:47 -0300
Re: "Program to an interface" - When to break a design pattern Roedy Green <see_website@mindprod.com.invalid> - 2011-05-05 16:41 -0700
Re: "Program to an interface" - When to break a design pattern Jim Janney <jjanney@shell.xmission.com> - 2011-05-05 22:47 -0600
Re: "Program to an interface" - When to break a design pattern Zapanaz <http://joecosby.com/code/mail.pl@foo.com> - 2011-05-05 23:28 -0700
Re: "Program to an interface" - When to break a design pattern Michal Kleczek <kleku75@gmail.com> - 2011-05-06 17:15 +0200
Re: "Program to an interface" - When to break a design pattern Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-05-06 20:53 -0300
Re: "Program to an interface" - When to break a design pattern Lew <noone@lewscanon.com> - 2011-05-06 21:39 -0400
Re: "Program to an interface" - When to break a design pattern Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-05-07 00:56 -0300
Re: "Program to an interface" - When to break a design pattern Michal Kleczek <kleku75@gmail.com> - 2011-05-08 12:24 +0200
Re: "Program to an interface" - When to break a design pattern Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-05-08 13:42 -0300
Re: "Program to an interface" - When to break a design pattern Michal Kleczek <kleku75@gmail.com> - 2011-05-09 11:04 +0200
Re: "Program to an interface" - When to break a design pattern Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-05-09 19:33 -0300
Re: "Program to an interface" - When to break a design pattern Michal Kleczek <kleku75@gmail.com> - 2011-05-10 15:51 +0200
Re: "Program to an interface" - When to break a design pattern Jim Janney <jjanney@shell.xmission.com> - 2011-05-10 13:15 -0600
Re: "Program to an interface" - When to break a design pattern Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-05-10 19:40 -0300
csiph-web