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

Groups > comp.lang.java.programmer > #22572

Re: BlueJ don't know what i did wrong

Show all headers | View raw

On 27/02/13 10:45, Arved Sandstrom wrote:
> On 02/26/2013 07:30 AM, lipska the kat wrote:
>> On 26/02/13 09:59, Arved Sandstrom wrote:
>>> On 02/26/2013 05:23 AM, lipska the kat wrote:

[snip]

>>>>
>>> A deque (double ended queue) is a queue generalization. Despite the
>>> name, a deque is not a queue, but a queue is a deque.
>>
>> You have this the wrong way round I'm afraid.
>> A Deque 'is a' Queue because it extends Queue, you can call Queue
>> methods on Deque but you cannot call Deque methods on Queue.
>> A Queue is most definitely NOT a Deque.
>>
>> These are first year comp sci concepts really.
> [ SNIP ]
>
> You want to read up on generalization and specialization.

======================= Generalization ==============================
http://en.wikipedia.org/wiki/Generalisation

... concept A(Queue) is considered a "generalization" of concept 
B(Deque) if and only if:

every instance of concept B (Deque) is also an instance of concept A 
(Queue); -- this is obviously the case as Deque extends Queue

and

there are instances of concept A(Queue) which are not instances of 
concept B(Deque) -- again true, you can't call Deque methods on Queue types
======================================================================

You appear to be arguing against this with your assertion that
"A deque (double ended queue) is a queue generalization"

In fact a Deque is a Queue *specialization*

============================ Specialization ==========================
http://en.wikipedia.org/wiki/Specialization_%28logic%29

... Concept B(Deque) is a "specialisation" of concept A(Queue) if and 
only if:

every instance of concept B (Deque) is also an instance of concept A 
(Queue); and

there are instances of concept A(Queue) which are not instances of 
concept B(Deque).

---see above
=====================================================================

Still not convinced ?

lipska

-- 
Lipska the Kat©: Troll hunter, sandbox destroyer
and farscape dreamer of Aeryn Sun

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

Thread

BlueJ don't know what i did wrong BlueJguywithoutskill <marvin.radke@htp-tel.de> - 2013-02-22 06:03 -0800
  Re: BlueJ don't know what i did wrong Joerg Meier <joergmmeier@arcor.de> - 2013-02-22 15:55 +0100
  Re: BlueJ don't know what i did wrong marvin.radke@htp-tel.de - 2013-02-22 07:13 -0800
    Re: BlueJ don't know what i did wrong Joerg Meier <joergmmeier@arcor.de> - 2013-02-22 16:24 +0100
      Re: BlueJ don't know what i did wrong marvin.radke@htp-tel.de - 2013-02-22 07:31 -0800
      Re: BlueJ don't know what i did wrong Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-02-22 10:50 -0500
  Re: BlueJ don't know what i did wrong markspace <markspace@nospam.nospam> - 2013-02-22 10:43 -0800
  Re: BlueJ don't know what i did wrong marvin.radke@htp-tel.de - 2013-02-24 02:27 -0800
    Re: BlueJ don't know what i did wrong Joerg Meier <joergmmeier@arcor.de> - 2013-02-24 14:54 +0100
      Re: BlueJ don't know what i did wrong marvin.radke@htp-tel.de - 2013-02-24 06:15 -0800
    Re: BlueJ don't know what i did wrong lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-02-24 15:04 +0000
    Re: BlueJ don't know what i did wrong lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-02-24 16:29 +0000
      Re: BlueJ don't know what i did wrong Joerg Meier <joergmmeier@arcor.de> - 2013-02-24 18:21 +0100
        Re: BlueJ don't know what i did wrong lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-02-24 17:43 +0000
          Re: BlueJ don't know what i did wrong Joerg Meier <joergmmeier@arcor.de> - 2013-02-24 20:04 +0100
            Re: BlueJ don't know what i did wrong lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-02-24 19:24 +0000
              Re: BlueJ don't know what i did wrong marvin.radke@htp-tel.de - 2013-02-25 01:52 -0800
                Re: BlueJ don't know what i did wrong lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-02-25 11:10 +0000
                Re: BlueJ don't know what i did wrong "John B. Matthews" <nospam@nospam.invalid> - 2013-02-25 07:50 -0500
                Re: BlueJ don't know what i did wrong lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-02-25 13:35 +0000
                Re: BlueJ don't know what i did wrong "John B. Matthews" <nospam@nospam.invalid> - 2013-02-25 13:52 -0500
                Re: BlueJ don't know what i did wrong lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-02-25 19:54 +0000
                Re: BlueJ don't know what i did wrong Lew <lewbloch@gmail.com> - 2013-02-25 14:26 -0800
                Re: BlueJ don't know what i did wrong lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-02-26 09:08 +0000
                Re: BlueJ don't know what i did wrong Arne Vajhøj <arne@vajhoej.dk> - 2013-02-25 22:05 -0500
                Re: BlueJ don't know what i did wrong Arne Vajhøj <arne@vajhoej.dk> - 2013-02-25 22:08 -0500
                Re: BlueJ don't know what i did wrong lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-02-26 09:23 +0000
                Re: BlueJ don't know what i did wrong Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-02-26 05:59 -0400
                Re: BlueJ don't know what i did wrong lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-02-26 11:30 +0000
                Re: BlueJ don't know what i did wrong Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-02-27 06:45 -0400
                Re: BlueJ don't know what i did wrong lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-02-27 11:58 +0000
                Re: BlueJ don't know what i did wrong lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-02-27 12:24 +0000
                Re: BlueJ don't know what i did wrong Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-02-27 22:40 -0400
                Re: BlueJ don't know what i did wrong lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-02-28 08:53 +0000
                Re: BlueJ don't know what i did wrong Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-02-28 17:14 -0400
                Re: BlueJ don't know what i did wrong lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-03-01 08:45 +0000
                Re: BlueJ don't know what i did wrong markspace <markspace@nospam.nospam> - 2013-02-26 08:33 -0800
                Re: BlueJ don't know what i did wrong Arne Vajhøj <arne@vajhoej.dk> - 2013-02-25 22:19 -0500
                Re: BlueJ don't know what i did wrong Arne Vajhøj <arne@vajhoej.dk> - 2013-02-25 22:02 -0500
                Re: BlueJ don't know what i did wrong marvin.radke@htp-tel.de - 2013-02-25 09:54 -0800
                Re: BlueJ don't know what i did wrong lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-02-25 18:25 +0000
                Re: BlueJ don't know what i did wrong Joerg Meier <joergmmeier@arcor.de> - 2013-02-26 16:13 +0100
                Re: BlueJ don't know what i did wrong lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-02-26 16:40 +0000
                Re: BlueJ don't know what i did wrong Joerg Meier <joergmmeier@arcor.de> - 2013-02-26 18:19 +0100
                Re: BlueJ don't know what i did wrong markspace <markspace@nospam.nospam> - 2013-02-25 08:34 -0800
    Re: BlueJ don't know what i did wrong Lew <lewbloch@gmail.com> - 2013-02-24 12:38 -0800

csiph-web