Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.java.programmer > #12551

Re: Aspect questions?

From Lew <noone@lewscanon.com>
Newsgroups comp.lang.java.programmer
Subject Re: Aspect questions?
Date 2012-02-29 23:06 -0800
Organization albasani.net
Message-ID <jin75c$8ci$1@news.albasani.net> (permalink)
References (18 earlier) <XnsA006B6A5992DDjpnasty@94.75.214.39> <jihabg$3oo$1@news.albasani.net> <XnsA008660779DFEjpnasty@94.75.214.39> <jilopr$lof$1@news.albasani.net> <XnsA008A84123C55jpnasty@94.75.214.39>

Show all headers | View raw

Novice wrote:
> Lew wrote:
>> So taking lists as the example:
>>
>>    List<String>  options = new ArrayList<>();
>>
>> I declared the 'options' variable as a 'List<String>', not as an
>> 'ArrayList<String>'. If I discover that the array-backed list wasn't
>> giving me the performance or other implementation-specific behavior I
>> need, but a linked list does, I can refactor more easily:
>>
>>    List<String>  options = new LinkedList<>();
>>
>> The rest of the program, depending only on the "list"ness and not the
>> "array"ness, is unharmed.
>>
>> (What performance differences are there? Excellent question! Pop quiz
>> - please answer this post with your answer - where would you find out
>> about performance characteristics of 'ArrayList<E>' and
>> 'LinkedList<E>'?)

I meant where specifically. You didn't show me where. You talked a lot about 
how you'd go about finding where, but you didn't actually follow your own advice.

>> Summary:
>> Interface: what to do
>> Class:     how to do it
>
> I need to understand what you've said a bit better before I try the pop
> quiz ;-)
>
> It makes perfect sense to me to figure out what a program needs to do
> before you worry about how it gets done. You've got to design a house - how
> many bedrooms, how many bathrooms, what style of house (ranch or bungalow
> or apartment building), etc. etc. - before you choose the exact fixtures.
>
> But when you talked about designing interfaces, I assumed you meant NEW interfaces.

No. I wasn't talking about designing interfaces. I was talking about writing a 
program.

> Your examples seem to be about selecting which of the existing
> interfaces - which kind of lists - you wanted. But those kinds already

Yes. There's a reason for that. It's because I was talking about selecting 
which existing interfaces you want to use.

> exist so you're really just choosing them, not inventing new ones to do new

Right. Precisely. Just so.

> things. It would be helpful to me if you also talked about new interfaces
> and how those come about at design time.

Give me an example of some unit of functionality you'd like to design, in 
broad terms, and I'll do just that.

> By the way, I completely see your point in the examples. I have already
> benefited from the same by using Collections. I use more Sets than Lists

Why do you use more sets than lists?

> and I will often start with a HashSet but if I start using it and find it
> doesn't have things in the order I wanted, it's a trivial thing to change
> it to another ordering by choosing a TreeSet or LinkedHashSet. That is
> REALLY convenient.
>
> Now that I think about it, I suppose I know enough to tackle the pop quiz
> after all.
>
> I have the feeling that I'm supposed to answer with something like "the
> API" or maybe based on something you said in one of your posts. Well, I'm

"You're supposed to answer"? What _is_ the answer? "The API" or "something you 
said" isn't an answer. That's like saying, "Where in the city will I find the 
post office" and you say, "There's a map somewhere". I am still left unable to 
mail a letter.

> going to "over-answer" the question and say this:

Sorry, that's actually under-answering.

> I know that the API or the various Java Tutorials (like the one on
> Collections) often gives clues about performance and tells you explicitly,

What clues? Where? Show me. I asked a specific question about specific classes.

> for example, that a HashSet normally performs best and a TreeSet worst with
> a LinkedHashSet typically performing almost as well as a HashSet. So that's
> obviously a good place to start.

"normally"? "performs"? "best"?

You described some useful strategies, but let's see what happens when you 
apply them to 'ArrayList<E>' and 'LinkedList<E>'.

And since you brought them up, the three 'Set' implementations you mention.

The questions above are to stimulate thought. The questions that follow are 
for you to answer here.

Without asking anyone else, but by research (which you should cite):

What are the performance differences (if any! - question every assumption in a 
question) between:
- 'ArrayList<E>' and 'LinkedList<E>'?
- 'HashSet<E>', 'TreeSet<E>' and 'LinkedHashSet<E>'?

What are the differences between:
- 'List<E>' and 'Set<E>'?

For your claim that "HashSet normally performs best", define:
- "normally"
- "performs"
- "best"

Since you get to define these terms, there might not be exactly a right 
answer. Instead, justify your definitions to whatever extent you feel they 
need it. Be careful - justifications like "the standard definition" do require 
citation of which standard.

Have fun.

-- 
Lew
Honi soit qui mal y pense.
http://upload.wikimedia.org/wikipedia/commons/c/cf/Friz.jpg

Back to comp.lang.java.programmer | Previous | Next — Previous in thread | Next in thread | Find similar

Thread

Aspect questions? Novice <novice@example..com> - 2012-02-24 20:10 +0000
  Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-24 13:05 -0800
    Re: Aspect questions? Novice <novice@example..com> - 2012-02-25 05:47 +0000
      Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-24 23:40 -0800
        Re: Aspect questions? Novice <novice@example..com> - 2012-02-25 17:02 +0000
          Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-25 12:08 -0800
            Re: Aspect questions? Novice <novice@example..com> - 2012-02-25 22:12 +0000
              Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-25 14:27 -0800
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-25 23:29 +0000
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-25 18:33 -0500
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-26 14:38 +0000
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-26 10:49 -0500
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-26 10:53 -0500
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-26 18:17 +0000
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-25 16:01 -0800
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-26 17:22 +0000
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-26 12:25 -0500
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-26 21:08 +0000
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-26 18:33 -0500
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-26 17:05 -0800
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-26 20:18 -0500
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-26 21:29 -0800
                Re: Aspect questions? Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-02-27 05:44 -0400
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-27 21:37 -0500
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-28 00:04 -0800
                Re: Aspect questions? Patricia Shanahan <pats@acm.org> - 2012-02-28 01:39 -0800
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-29 14:54 +0000
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-28 17:24 -0500
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-27 04:53 +0000
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-03-02 17:08 -0500
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-27 05:12 +0000
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-26 21:38 -0800
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-27 17:27 +0000
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-27 12:22 -0800
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-27 22:50 +0000
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-27 17:24 -0800
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-29 15:00 +0000
                Re: Aspect questions? Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-02-29 09:14 -0800
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-29 09:55 -0800
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-29 21:31 +0000
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-29 23:06 -0800
                Re: Aspect questions? Novice <novice@example..com> - 2012-03-02 04:33 +0000
                Re: Aspect questions? Novice <novice@example..com> - 2012-03-04 23:00 +0000
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-03-04 17:07 -0800
                Re: Aspect questions? Novice <novice@example..com> - 2012-03-05 15:33 +0000
                JavaDoc linking (Was: Aspect questions?) Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-03-05 08:38 -0800
                Re: JavaDoc linking (Was: Aspect questions?) Novice <novice@example..com> - 2012-03-05 17:40 +0000
                Re: JavaDoc linking (Was: Aspect questions?) Patricia Shanahan <pats@acm.org> - 2012-03-05 21:25 -0800
                Re: JavaDoc linking (Was: Aspect questions?) Arne Vajhøj <arne@vajhoej.dk> - 2012-03-06 17:23 -0500
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-03-05 23:45 -0800
                Re: Aspect questions? Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-03-06 06:03 -0400
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-03-06 21:05 -0800
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-03-02 17:11 -0500
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-03-02 17:09 -0500
                Re: Aspect questions? Martin Gregorie <martin@address-in-sig.invalid> - 2012-02-26 23:43 +0000
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-27 05:20 +0000
                Re: Aspect questions? Patricia Shanahan <pats@acm.org> - 2012-02-26 21:32 -0800
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-27 17:36 +0000
                Re: Aspect questions? Jeff Higgins <jeff@invalid.invalid> - 2012-02-27 13:18 -0500
                Re: Aspect questions? Jeff Higgins <jeff@invalid.invalid> - 2012-02-27 14:05 -0500
                Re: Aspect questions? Jeff Higgins <jeff@invalid.invalid> - 2012-02-27 14:33 -0500
                Re: Aspect questions? Jeff Higgins <jeff@invalid.invalid> - 2012-02-27 14:53 -0500
                Re: Aspect questions? Jeff Higgins <jeff@invalid.invalid> - 2012-02-27 15:16 -0500
                Re: Aspect questions? Jeff Higgins <jeff@invalid.invalid> - 2012-02-27 17:57 -0500
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-27 22:59 +0000
                Re: Aspect questions? Jeff Higgins <jeff@invalid.invalid> - 2012-02-28 05:50 -0500
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-29 15:03 +0000
                Re: Aspect questions? Patricia Shanahan <pats@acm.org> - 2012-02-27 13:17 -0800
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-27 22:55 +0000
                Re: Aspect questions? Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-02-27 05:58 -0400
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-27 18:14 +0000
                Re: Aspect questions? Martin Gregorie <martin@address-in-sig.invalid> - 2012-02-28 00:12 +0000
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-28 02:04 +0000
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-27 21:22 -0500
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-29 15:11 +0000
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-03-02 17:14 -0500
                Re: Aspect questions? Martin Gregorie <martin@address-in-sig.invalid> - 2012-02-28 23:09 +0000
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-29 15:25 +0000
                Re: Aspect questions? Martin Gregorie <martin@address-in-sig.invalid> - 2012-03-01 00:22 +0000
                Re: Aspect questions? Novice <novice@example..com> - 2012-03-01 01:44 +0000
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-29 23:24 -0800
                Re: Aspect questions? Martin Gregorie <martin@address-in-sig.invalid> - 2012-03-01 21:19 +0000
                Re: Aspect questions? Novice <novice@example..com> - 2012-03-02 01:52 +0000
                Re: Aspect questions? Martin Gregorie <martin@address-in-sig.invalid> - 2012-03-03 01:39 +0000
                Re: Aspect questions? Novice <novice@example..com> - 2012-03-05 15:38 +0000
                Re: Aspect questions? Martin Gregorie <martin@address-in-sig.invalid> - 2012-03-05 22:50 +0000
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-03-05 23:46 -0800
                Re: Aspect questions? Patricia Shanahan <pats@acm.org> - 2012-03-06 08:14 -0800
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-03-06 21:23 -0800
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-03-08 20:10 -0500
                Re: Aspect questions? Novice <novice@example..com> - 2012-03-02 01:49 +0000
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-03-01 22:38 -0800
                Re: Aspect questions? Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-03-02 06:05 -0400
                Re: Aspect questions? Novice <novice@example..com> - 2012-03-02 14:25 +0000
                Re: Aspect questions? Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-03-02 18:10 -0400
                Re: Aspect questions? Novice <novice@example..com> - 2012-03-02 14:12 +0000
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-03-02 08:57 -0800
                Re: Aspect questions? Novice <novice@example..com> - 2012-03-05 15:57 +0000
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-03-05 23:48 -0800
                Re: Aspect questions? Novice <novice@example..com> - 2012-03-07 20:33 +0000
                Re: Aspect questions? Lew <lewbloch@gmail.com> - 2012-03-07 13:09 -0800
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-03-02 17:20 -0500
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-03-02 14:28 -0800
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-03-02 17:16 -0500
                Re: Aspect questions? markspace <-@.> - 2012-02-26 10:10 -0800
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-26 20:52 +0000
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-26 13:48 -0800
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-26 13:47 -0800
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-26 18:40 -0500
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-26 18:36 -0500
                Re: Aspect questions? markspace <-@.> - 2012-02-26 16:04 -0800
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-26 19:38 -0500
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-26 17:09 -0800
                Re: Aspect questions? Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-02-26 20:08 -0400
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-26 19:43 -0500
                Re: Aspect questions? Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-02-27 22:03 -0400
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-27 21:18 -0500
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-26 13:43 -0800
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-27 01:11 +0000
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-26 21:49 -0800
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-27 18:37 +0000
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-27 12:28 -0800
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-28 00:55 +0000
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-27 17:37 -0800
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-29 15:57 +0000
                Re: Aspect questions? Leif Roar Moldskred <leifm@dimnakorr.com> - 2012-02-28 03:21 -0600
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-28 09:19 -0800
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-27 21:12 -0500
                Re: Aspect questions? Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-02-28 05:59 -0400
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-28 17:27 -0500
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-29 16:07 +0000
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-03-02 17:26 -0500
              Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-25 18:22 -0500
                Re: Aspect questions? markspace <-@.> - 2012-02-25 20:22 -0800
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-25 22:20 -0800
                Re: Aspect questions? markspace <-@.> - 2012-02-26 00:04 -0800
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-26 00:21 -0800
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-26 00:33 -0800
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-26 10:43 -0500
                Re: Aspect questions? Martin Gregorie <martin@address-in-sig.invalid> - 2012-02-26 11:18 +0000
                Re: Aspect questions? Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-02-26 11:04 -0400
                Re: Aspect questions? Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-02-26 10:22 -0400
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-26 21:04 +0000
                Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-26 14:01 -0800
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-26 18:46 -0500
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-26 09:50 -0500
                Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-26 10:38 -0500
                Re: Aspect questions? Novice <novice@example..com> - 2012-02-26 20:49 +0000
      Re: Aspect questions? jlp <jlp@jlp.com> - 2012-02-25 09:47 +0100
        Re: Aspect questions? Novice <novice@example..com> - 2012-02-25 17:03 +0000
          Re: Aspect questions? jlp <jlp@jlp.com> - 2012-02-25 20:02 +0100
      Re: Aspect questions? Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-02-25 10:20 -0400
        Re: Aspect questions? markspace <-@.> - 2012-02-25 08:18 -0800
          Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-25 12:04 -0500
        Re: Aspect questions? Novice <novice@example..com> - 2012-02-25 17:17 +0000
          Re: Aspect questions? Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-02-25 18:40 -0400
          Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-25 18:18 -0500
      Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-25 09:21 -0500
      Re: Aspect questions? Roedy Green <see_website@mindprod.com.invalid> - 2012-02-25 14:35 -0800
  Re: Aspect questions? markspace <-@.> - 2012-02-24 14:30 -0800
    Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-24 19:47 -0500
      Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-24 20:52 -0800
        Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-25 09:31 -0500
        Re: Aspect questions? Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-02-25 11:05 -0400
          Re: Aspect questions? Lew <noone@lewscanon.com> - 2012-02-25 12:20 -0800
  Re: Aspect questions? Arne Vajhøj <arne@vajhoej.dk> - 2012-02-24 19:00 -0500
  Re: Aspect questions? Tom Anderson <twic@urchin.earth.li> - 2012-02-25 00:22 +0000

csiph-web