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Groups > comp.lang.java.programmer > #24437

Re: About java program.

From Arved Sandstrom <asandstrom2@eastlink.ca>
Newsgroups comp.lang.java.programmer
Subject Re: About java program.
References (1 earlier) <b24an6FlpvpU1@mid.individual.net> <UoednTl5R618JiDMnZ2dnUVZ8iadnZ2d@bt.com> <b263siF2vkkU1@mid.individual.net> <uBDvt.60965$5i1.39234@newsfe15.iad> <ILKdnZ-vg53OjiLMnZ2dnUVZ7tmdnZ2d@bt.com>
Message-ID <zSGvt.13901$9m5.2187@newsfe26.iad> (permalink)
Organization Public Usenet Newsgroup Access
Date 2013-06-17 13:32 -0300

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On 06/17/2013 10:46 AM, lipska the kat wrote:
> On 17/06/13 13:49, Arved Sandstrom wrote:
>> On 06/16/2013 12:28 PM, Robert Klemme wrote:
>>> On 16.06.2013 15:21, lipska the kat wrote:
>>>> On 16/06/13 00:12, Robert Klemme wrote:
>>>>> On 15.06.2013 22:38, rajbhaumik@gmail.com wrote:
>>>>>> import acm.program.*;
>>>>>> public class askYesNoQuestion extends ConsoleProgram {
>>>>>>     public void run(){
>>>>>>         String str=readLine("Would you like instructions");
>>>>>>         println(askYesNoquestion(str));
>>>>>>     }
>>>>>> 7.        private boolean askYesNoquestion (String str){
>>>>>>             if(str.equals("yes"))return true;
>>>>>>             if(str.equals("no")) return false;
>>>>>>     }
>>>>>>
>>>>>> }
>>>>>> the false is that , the program cannot be executed, because no 7
>>>>>> said, this method must return a type of boolean.
>>>>>
>>>>
>>>> One possible solution (not compiled or tested)
>>>>
>>>> private boolean askYesNoquestion (String str){
>>>>     boolean response = false;
>>>>     if(str.equals("yes")){
>>>>         response = true;
>>>>     }
>>>>     return response;
>>>> }
>
> [snip]
>
>> To the original point, I agree to an extent. But the actual idiom that
>> lipska used is not bad in general, if you're used to single return. It's
>> sort of like *always* providing braces for conditionals, even for one
>> liners, defensive coding in part, but also adhering to personal coding
>> style.
>
> ... and what is your opinion of defensive coding?

Not far different from yours, apparently.

> Anyone who has ever written software to interact with a user via a
> device interface knows (or should know) that defensive coding is de-riguer.
>
> If you don't want the device to crash every time someone does something
> unexpected you need to anticipate no only the unexpected but the
> unanticipated. There is *no* room for error.
>
> This discipline is hard to learn and once learned even harder to
> un-learn. This is why I don't like things like
>
> return str.equals("yes");
>
> It's lazy coding and harder to understand than my example and yes, I
> realize that it's only a one liner but the next stage in the
> 'development' of this style is
>
> if(something){
>     return something;
> }
> else if(something else){
>     return something else;
> }
> else{
>     return some other value
> }
>
> It is much easier to understand and debug
> the following
>
> type var;
>
> if(something){
>     var = something;
> }
> else if(something else){
>     var = something else;
> }
> else{
>     var = some other value
> }
>
> return var;
>
> If I was doing a proper job and not just providing a simple example I
> would have had a pre-condition on the method *and* exception handling
> *and* braces around every conditional, even one liners,
> *and* a fallback position if the operation was mission critical. So yes,
> it's my personal style learned from painful experience.
>
> Thank you for understanding
>
> lipska
>
Generally speaking all of this boils down to one thing: errors happen 
when the same developer - you, me, anyone - has white-box knowledge of, 
and maybe responsibility for, both called *and* calling code. This 
extends even to method lexical scope where a developer may write some 
stuff that makes assumptions about his or her own code in the same 
method 50 lines previous.

I daresay that this state of affairs is the norm. Sure, a whole bunch of 
developers work on NASA or defense or avionics or Big Healthcare type 
projects where you've got a great deal of imposed rigor. But very likely 
most developers own a whole bunch of code, and I'm sure that a large 
number of us write entire apps. For example, as a software consultant I 
often do analyze, design and code entire applications.

So, given this, it's necessary to be somewhat schizophrenic - when 
working on method X in class A, and it's called by method Y in class B 
and method Z in class C, and you are writing *all* of them, you need to 
wear 3 hats. And by extension N hats as you implement the entire app, 
and even more because you're also doing design and analysis.

God forbid that the developer also does the functional and integration 
and system testing, but this is not rare. But let's ignore that aspect 
of real life. :-)

If there actually is a good sized team the same considerations apply. 
The nature of the beast these days is that often developers have 
visibility into calling code that they don't have responsibility for, 
because they do git or svn or hg, and they inevitably see way more than 
they ought to.

I've rarely seen it done, because it adds substantial cost, but a better 
approach would be to have each developer assigned (a) method(s) in a 
class just write the class, and also be given time to write necessary 
scaffolding in the form of tests that exercises their code. They never 
see the complete codebase. The advantage of this is that they write to a 
written design spec and not to knowledge of other code, and that they 
have also necessarily written useful tests.

Robert's method, the NPE-safe one that also types the method parameter, 
is not objectionable to me precisely because the equals is encapsulated 
in a method that constrains the type. Trivial methods of this sort are 
quite handy as private methods and make the code more robust, since 
equals() by itself is too Wild West.

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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Thread

About java program. rajbhaumik@gmail.com - 2013-06-15 13:38 -0700
  Re: About java program. Arne Vajhøj <arne@vajhoej.dk> - 2013-06-15 16:50 -0400
  Re: About java program. Robert Klemme <shortcutter@googlemail.com> - 2013-06-16 01:12 +0200
    Re: About java program. lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-06-16 14:21 +0100
      Re: About java program. Robert Klemme <shortcutter@googlemail.com> - 2013-06-16 17:28 +0200
        Re: About java program. lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-06-16 19:52 +0100
          Re: About java program. Arne Vajhøj <arne@vajhoej.dk> - 2013-06-16 15:50 -0400
        Re: About java program. lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-06-17 09:36 +0100
        Re: About java program. Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-06-17 09:49 -0300
          Re: About java program. lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-06-17 14:46 +0100
            Re: About java program. Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-06-17 13:32 -0300
            Re: About java program. Joerg Meier <joergmmeier@arcor.de> - 2013-06-17 20:32 +0200
              Re: About java program. Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-06-17 14:49 -0400
                Re: About java program. Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-06-17 18:38 -0300
                Re: About java program. Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-06-17 18:30 -0400
                Re: About java program. Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-06-18 17:33 -0300
                Re: About java program. Arne Vajhøj <arne@vajhoej.dk> - 2013-07-04 22:56 -0400
                Re: About java program. Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2013-06-18 00:13 +0200
                Re: About java program. Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-06-18 17:50 -0300
                Re: About java program. lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-06-19 08:50 +0100
                Re: About java program. Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-06-19 15:16 -0300
                Re: About java program. Lew <lewbloch@gmail.com> - 2013-06-19 16:20 -0700
                Re: About java program. Jeff Higgins <jeff@invalid.invalid> - 2013-07-07 13:31 -0400
                Re: About java program. Jeff Higgins <jeff@invalid.invalid> - 2013-07-07 18:16 -0400
                Re: About java program. Jeff Higgins <jeff@invalid.invalid> - 2013-07-07 19:21 -0400
                Re: About java program. Jeff Higgins <jeff@invalid.invalid> - 2013-07-07 20:07 -0400
                Re: About java program. Jeff Higgins <jeff@invalid.invalid> - 2013-07-07 20:21 -0400
                Re: About java program. Jeff Higgins <jeff@invalid.invalid> - 2013-07-07 20:40 -0400
                Re: About java program. Jeff Higgins <jeff@invalid.invalid> - 2013-07-07 22:20 -0400
                Re: About java program. Lew <lewbloch@gmail.com> - 2013-07-07 21:47 -0700
                Re: About java program. Jeff Higgins <jeff@invalid.invalid> - 2013-07-08 06:58 -0400
                Re: About java program. Jeff Higgins <jeff@invalid.invalid> - 2013-07-08 08:07 -0400
                Re: About java program. Jeff Higgins <jeff@invalid.invalid> - 2013-07-08 08:58 -0400
                Re: About java program. Jeff Higgins <jeff@invalid.invalid> - 2013-07-08 09:18 -0400
                Re: About java program. Jeff Higgins <jeff@invalid.invalid> - 2013-07-08 09:47 -0400
                Re: About java program. Jeff Higgins <jeff@invalid.invalid> - 2013-07-08 10:07 -0400
                Re: About java program. Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2013-06-19 16:42 +0200
                Re: About java program. Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-06-20 23:33 -0300
                Re: About java program. Martin Gregorie <martin@address-in-sig.invalid> - 2013-06-21 04:16 +0000
                Re: About java program. Joerg Meier <joergmmeier@arcor.de> - 2013-06-21 12:27 +0200
                Re: About java program. Martin Gregorie <martin@address-in-sig.invalid> - 2013-06-21 21:14 +0000
                Re: About java program. Joerg Meier <joergmmeier@arcor.de> - 2013-06-21 23:37 +0200
                Re: About java program. Martin Gregorie <martin@address-in-sig.invalid> - 2013-06-21 23:42 +0000
                Re: About java program. Gene Wirchenko <genew@telus.net> - 2013-06-24 13:00 -0700
                Re: About java program. Martin Gregorie <martin@address-in-sig.invalid> - 2013-06-24 21:29 +0000
                Re: About java program. Martin Gregorie <martin@address-in-sig.invalid> - 2013-06-24 21:42 +0000
                Re: About java program. Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-06-21 23:59 -0300
                Re: About java program. Martin Gregorie <martin@address-in-sig.invalid> - 2013-06-22 13:30 +0000
                Re: About java program. Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2013-06-21 16:24 +0200
                Re: About java program. Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-06-21 22:39 -0300
                Re: About java program. Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2013-06-22 19:25 +0200
                Re: About java program. lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-06-22 19:41 +0100
                Re: About java program. Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2013-06-23 03:53 +0200
                Re: About java program. lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-06-23 09:21 +0100
                Re: About java program. Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2013-06-24 18:57 +0200
                Re: About java program. lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-06-24 18:14 +0100
                Re: About java program. lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-06-22 09:03 +0100
                Re: About java program. Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2013-06-22 19:26 +0200
                Re: About java program. lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-06-22 18:51 +0100
                Re: About java program. Arne Vajhøj <arne@vajhoej.dk> - 2013-07-04 22:58 -0400
                Re: About java program. Joerg Meier <joergmmeier@arcor.de> - 2013-06-19 00:38 +0200
                Re: About java program. Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-06-18 18:56 -0400
                Re: About java program. Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-06-18 21:26 -0300
                Re: About java program. Robert Klemme <shortcutter@googlemail.com> - 2013-06-19 21:20 +0200
                Re: About java program. Sven Köhler <remove-sven.koehler@gmail.com> - 2013-06-20 11:23 +0300
                Re: About java program. Robert Klemme <shortcutter@googlemail.com> - 2013-06-20 19:18 +0200
                Re: About java program. blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2013-07-15 20:20 +0000
                Re: About java program. lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-06-19 09:14 +0100
                Re: About java program. lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-06-19 09:11 +0100
                Re: About java program. Arne Vajhøj <arne@vajhoej.dk> - 2013-07-04 23:11 -0400
                Re: About java program. lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-07-05 09:13 +0100
                Re: About java program. Robert Klemme <shortcutter@googlemail.com> - 2013-07-05 23:15 +0200
                Re: About java program. Arne Vajhøj <arne@vajhoej.dk> - 2013-07-05 22:03 -0400
                Re: About java program. Robert Klemme <shortcutter@googlemail.com> - 2013-07-06 13:01 +0200
                Re: About java program. lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-07-06 13:43 +0100
                Re: About java program. Martin Gregorie <martin@address-in-sig.invalid> - 2013-07-06 14:17 +0000
                Re: About java program. Arne Vajhøj <arne@vajhoej.dk> - 2013-07-06 16:18 -0400
                Re: About java program. lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-07-06 21:42 +0100
                Re: About java program. lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-07-06 09:16 +0100
                Re: About java program. Robert Klemme <shortcutter@googlemail.com> - 2013-07-06 13:14 +0200
                Re: About java program. Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-07-06 08:22 -0400
                Re: About java program. Robert Klemme <shortcutter@googlemail.com> - 2013-07-07 20:43 +0200
                Re: About java program. Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-07-07 18:07 -0400
                Re: About java program. Arne Vajhøj <arne@vajhoej.dk> - 2013-07-07 19:35 -0400
                Re: About java program. Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-07-07 20:42 -0400
                Re: About java program. Robert Klemme <shortcutter@googlemail.com> - 2013-07-08 20:50 +0200
                Re: About java program. Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-07-08 15:01 -0400
                Re: About java program. Robert Klemme <shortcutter@googlemail.com> - 2013-07-08 23:29 +0200
                Re: About java program. Arne Vajhøj <arne@vajhoej.dk> - 2013-07-06 16:27 -0400
                Re: About java program. Lew <lewbloch@gmail.com> - 2013-07-06 13:41 -0700
                Re: About java program. Arne Vajhøj <arne@vajhoej.dk> - 2013-07-05 21:59 -0400
              Re: About java program. lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-06-17 21:06 +0100
            Re: About java program. Joshua Cranmer 🐧 <Pidgeot18@verizon.invalid> - 2013-06-17 17:36 -0500
              Re: About java program. Robert Klemme <shortcutter@googlemail.com> - 2013-06-18 08:24 +0200
              Re: About java program. lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-06-18 09:03 +0100
                Re: About java program. Joshua Cranmer 🐧 <Pidgeot18@verizon.invalid> - 2013-06-18 13:07 -0500
                Re: About java program. Lew <lewbloch@gmail.com> - 2013-06-18 14:48 -0700
                Re: About java program. lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-06-19 08:36 +0100
              Re: About java program. Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-06-18 23:33 -0300
                Re: About java program. lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-06-19 08:34 +0100
            Re: About java program. Arne Vajhøj <arne@vajhoej.dk> - 2013-07-04 22:53 -0400
  Re: About java program. Roedy Green <see_website@mindprod.com.invalid> - 2013-06-16 07:04 -0700
  Re: About java program. Jeff Higgins <jeff@invalid.invalid> - 2013-06-18 04:06 -0400

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