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Groups > comp.lang.java.programmer > #3622

Re: "Program to an interface" - When to break a design pattern

From Roedy Green <see_website@mindprod.com.invalid>
Newsgroups comp.lang.java.programmer
Subject Re: "Program to an interface" - When to break a design pattern
Date 2011-05-05 16:41 -0700
Organization Canadian Mind Products
Message-ID <v3d6s6li6rgq2u28pversmjl1l913fjf0i@4ax.com> (permalink)
References <9dt5s6dalhetgfe99qs92c02hf0dbas44e@4ax.com>

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On Thu, 05 May 2011 12:21:55 -0700, Zapanaz
<http://joecosby.com/code/mail.pl@foo.com> wrote, quoted or indirectly
quoted someone who said :

>The problem is, where I'm creating sortedMap above, I need the map to
>retain the insertion order. If what's returned actually is a Map,
>rather than a LinkedHashMap, then the results the user actually sees
>are going to be in the wrong order. Making things worse, in this case,
>nothing would actually break, only the end user would notice anything
>was actually wrong.

The idea of an interface is you should be able to substitute some
other implementation and all should work unmodified.  That is not the
case with the interface you chose.  You need to either find or create
an interface that nails down all the desired behaviour, or use the
original actual implementation.

I am not a big fan of this pattern for the following reasons:
1. it slows down access.
2. it obfuscates just what the code is using NOW for the
implementation.
3. It is more verbose, giving you one more thing you have to eyeball
carefully and make dance through the genericity hoops. That makes for
buggier code.

The main place it would pay off is if you plan to later do some fine
tuning, and want to leave open the option of easily substituting your
own tuned collection classes.
-- 
Roedy Green Canadian Mind Products
http://mindprod.com
Politicians complain that Kindles and iBooks are killing jobs by 
destroying the paper book industry.  I see it that they have create a way 
to produce books for less than a third the cost without destroying forests 
and emitting greenhouse gases in the process.  They have created wealth.  
They are encouraging literacy and cutting the costs of education.  

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Thread

"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 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

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