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Groups > comp.lang.java.programmer > #2949
| From | Tom Anderson <twic@urchin.earth.li> |
|---|---|
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: calling own methods from constructor |
| Date | 2011-04-07 23:05 +0100 |
| Organization | Stack Usenet News Service |
| Message-ID | <alpine.DEB.2.00.1104072303480.25031@urchin.earth.li> (permalink) |
| References | <slrnippkd9.phi.avl@gamma.logic.tuwien.ac.at> <2011040622233261380-angrybaldguy@gmailcom> <2pzko2f2nx.fsf@shell.xmission.com> |
On Thu, 7 Apr 2011, Jim Janney wrote:
> Owen Jacobson <angrybaldguy@gmail.com> writes:
>
>> public class Foo {
>> public Foo() {
>> // internalInit is private, therefore final
>> this.internalInit();
>> }
>>
>> public /* virtual */ void virtualMethod() {
>> System.out.println("Override me! I dare you.");
>> }
>>
>> private void internalInit() {
>> // Whups! 'this' is not always fully initialized.
>> this.virtualMethod();
>> }
>> }
>
> public class Bar extends Foo {
> public Bar() {
> super();
> System.out.println("Two guys walk into a...");
> }
>
> @override
> public void virtualMethod() {
> throw new Exception("the bar is closed");
> }
> }
>
> In Java evaluating new Bar() will throw an exception. But in C++ the
> equivalent code would print
>
> Override me! I dare you.
> Two guys walk into a...
>
> In effect, until the constructor of Foo completes, the object is
> considered to be an instance of Foo, so calls to virtualMethod() to to
> Foo.virtualMethod even if it has been overridden. After the super
> constructor completes, the object is treated as an instance of Bar, so
> evaluating new Bar().virtualMethod() would print two lines and then
> throw an exception.
I recoil in horror.
> I've been surprised by this behaviour in C++ enough times that I'm not
> sure that it has the better approach. But a solution does exist.
That's slightly like solving toothache by amputating your head.
tom
--
Many of us adopted the File's slang as our own, feeling that we'd found a
tangible sign of the community of minds we'd half-guessed to be out there.
Back to comp.lang.java.programmer | Previous | Next — Previous in thread | Next in thread | Find similar
calling own methods from constructor Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-04-06 20:48 +0000
Re: calling own methods from constructor Tom Anderson <twic@urchin.earth.li> - 2011-04-06 23:06 +0100
Re: calling own methods from constructor Lew <noone@lewscanon.com> - 2011-04-06 18:24 -0400
Re: calling own methods from constructor Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-04-07 08:44 +0000
Re: calling own methods from constructor Robert Klemme <shortcutter@googlemail.com> - 2011-04-07 04:14 -0700
Re: calling own methods from constructor Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-04-07 12:32 +0000
Re: calling own methods from constructor Robert Klemme <shortcutter@googlemail.com> - 2011-04-07 05:55 -0700
Re: calling own methods from constructor Lew <lew@lewscanon.com> - 2011-04-07 08:10 -0700
Re: calling own methods from constructor Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-04-07 20:31 +0000
Re: calling own methods from constructor Lew <lew@lewscanon.com> - 2011-04-07 14:10 -0700
Re: calling own methods from constructor Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-04-07 22:15 +0000
Re: calling own methods from constructor Lew <noone@lewscanon.com> - 2011-04-07 21:22 -0400
Re: calling own methods from constructor Tom Anderson <twic@urchin.earth.li> - 2011-04-07 23:08 +0100
Re: calling own methods from constructor Lew <noone@lewscanon.com> - 2011-04-07 21:24 -0400
Re: calling own methods from constructor "Mike Schilling" <mscottschilling@hotmail.com> - 2011-04-09 22:06 -0700
Re: calling own methods from constructor Tom Anderson <twic@urchin.earth.li> - 2011-04-07 23:10 +0100
Re: calling own methods from constructor Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-04-07 22:24 +0000
Re: calling own methods from constructor Lew <noone@lewscanon.com> - 2011-04-07 07:19 -0400
Re: calling own methods from constructor Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-04-07 12:24 +0000
Re: calling own methods from constructor Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-04-06 20:46 -0400
Re: calling own methods from constructor Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-04-07 08:36 +0000
Re: calling own methods from constructor Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-04-07 07:16 -0300
Re: calling own methods from constructor Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-04-07 11:26 +0000
Re: calling own methods from constructor Paul Cager <paul.cager@googlemail.com> - 2011-04-07 03:20 -0700
Re: calling own methods from constructor Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-04-07 11:36 +0000
Re: calling own methods from constructor Owen Jacobson <angrybaldguy@gmail.com> - 2011-04-06 22:23 -0400
Re: calling own methods from constructor Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-04-07 09:13 +0000
Re: calling own methods from constructor Tobias Blass <tobiasblass@gmx.net> - 2011-04-07 10:58 +0000
Re: calling own methods from constructor Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-04-07 12:19 +0000
Re: calling own methods from constructor Alessio Stalla <alessiostalla@gmail.com> - 2011-04-07 10:40 -0700
Re: calling own methods from constructor Tobias Blass <tobiasblass@gmx.net> - 2011-04-07 19:00 +0000
Re: calling own methods from constructor Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-04-07 20:11 +0000
Re: calling own methods from constructor Jim Janney <jjanney@shell.xmission.com> - 2011-04-07 14:36 -0600
Re: calling own methods from constructor Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-04-07 20:59 -0400
Re: calling own methods from constructor Jim Janney <jjanney@shell.xmission.com> - 2011-04-07 10:26 -0600
Re: calling own methods from constructor Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-04-07 20:16 +0000
Re: calling own methods from constructor Lew <lew@lewscanon.com> - 2011-04-07 14:05 -0700
Re: calling own methods from constructor Jim Janney <jjanney@shell.xmission.com> - 2011-04-07 16:15 -0600
Re: calling own methods from constructor Lew <noone@lewscanon.com> - 2011-04-07 21:28 -0400
Re: calling own methods from constructor Owen Jacobson <angrybaldguy@gmail.com> - 2011-04-07 23:21 -0400
Re: calling own methods from constructor Owen Jacobson <angrybaldguy@gmail.com> - 2011-04-07 23:39 -0400
Re: calling own methods from constructor Owen Jacobson <angrybaldguy@gmail.com> - 2011-04-07 23:58 -0400
Re: calling own methods from constructor Tom Anderson <twic@urchin.earth.li> - 2011-04-08 20:32 +0100
Re: calling own methods from constructor Tom Anderson <twic@urchin.earth.li> - 2011-04-07 23:05 +0100
Re: calling own methods from constructor Jim Janney <jjanney@shell.xmission.com> - 2011-04-07 17:38 -0600
Re: calling own methods from constructor Roedy Green <see_website@mindprod.com.invalid> - 2011-04-07 03:20 -0700
Re: calling own methods from constructor Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-04-07 11:32 +0000
Re: calling own methods from constructor Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-04-08 01:51 +0200
Re: calling own methods from constructor Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-04-08 01:56 +0200
Re: calling own methods from constructor Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-04-08 09:30 +0000
Re: calling own methods from constructor Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-04-08 20:02 +0200
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