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Groups > comp.lang.java.programmer > #26676
| From | v_borchert@despammed.com (Volker Borchert) |
|---|---|
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: Alternatives languages on the JVM: which one or is there no alternative? |
| Date | 2013-11-29 23:22 +0000 |
| Organization | Private site at Eddersheim, Germany |
| Message-ID | <l7b7jt$j0j$1@Gaia.teknon.de> (permalink) |
| References | <b61c37c4-1b86-4b63-8ed1-fa5834eb638e@googlegroups.com> <l733pd$7kk$1@Gaia.teknon.de> <bfklnaFis1vU1@mid.individual.net> <l73v2h$f22$1@Gaia.teknon.de> <bfn86fF4te5U1@mid.individual.net> |
Robert Klemme wrote:
> What does dynamic_cast in C++ do differently? As far as I am informed
> it involves a type check as well. I mean, you can have the same in Java
> by catching the exception (which is what you need to do in C++ IIRC).
No you don't, that is exactly the raison d'etre of dynamic_cast.
if (o instanceof C) {
final C c = (C) o;
// do something with c
}
does _two_ typechecks
final C c = dynamic_cast<C>(o);
if (c != null) {
// do something with c
}
would do _one_ typecheck and a cheap IFNONNULL
> > class Foo<T> {
> > // nonstatic inner class uzes 4 bytes for the
> > // implicit this$0 and 4 more bytes padding
> > class TPtr<T> extends WeakReference<T> {
> > Foo foo() {
> > return Foo.this;
> > }
> > }
> >
> > void gced() {
> > }
> > }
>
> Since Foo inherits Object you could as well make Foo<T> inherit
> WeakReference<T> avoiding the additional bytes per instance.
Sorry, I forgot the "extends Bar<T>".
> I find it difficult to discuss this without knowing more about your
> requirements and situation. But then again, maybe you don't want or
> cannot disclose that.
One example, for a Cache<Key,Value> that supports mixed flavor Value
references, and a subclass which additionally has entries doubly
linked, somewhat similar to LinkedHashMap, I want
AbstractEntry<K,V> WeakReference<V>
| |
| |
/ \ |
+---------------+---+----------+-------------+ |
| | | |
| | | |
AbstractLinkedEntry<K,V> StrongEntry<K,V> | |
| | | |
| | | |
+---------------+---+----------+ +--+---+--+
| \ / \ /
| | |
| | |
| StrongLinkedEntry<K,V> WeakEntry<K,V>
| |
| |
+------------------------------+---+--------------+
\ /
|
|
WeakLinkedEntry<K,V>
(soft flavor omitted for safe of readability)
--
"I'm a doctor, not a mechanic." Dr Leonard McCoy <mccoy@ncc1701.starfleet.fed>
"I'm a mechanic, not a doctor." Volker Borchert <v_borchert@despammed.com>
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Alternatives languages on the JVM: which one or is there no alternative? Saxo <jeti789@web.de> - 2013-11-25 03:09 -0800
Re: Alternatives languages on the JVM: which one or is there no alternative? Silvio <silvio@internet.com> - 2013-11-25 12:46 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? Saxo <jeti789@web.de> - 2013-11-25 05:20 -0800
Re: Alternatives languages on the JVM: which one or is there no alternative? Robert Klemme <shortcutter@googlemail.com> - 2013-11-25 22:10 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? Saxo <jeti789@web.de> - 2013-11-25 14:34 -0800
Re: Alternatives languages on the JVM: which one or is there no alternative? Silvio <silvio@internet.com> - 2013-11-26 08:54 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? Robert Klemme <shortcutter@googlemail.com> - 2013-11-26 00:29 -0800
Re: Alternatives languages on the JVM: which one or is there no alternative? Silvio <silvio@internet.com> - 2013-11-26 15:29 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? Arne Vajhøj <arne@vajhoej.dk> - 2013-11-26 21:55 -0500
Re: Alternatives languages on the JVM: which one or is there no alternative? Silvio <silvio@internet.com> - 2013-11-27 08:59 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? Joerg Meier <joergmmeier@arcor.de> - 2013-11-27 10:41 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? Silvio <silvio@internet.com> - 2013-11-28 12:48 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? leif.roar@invalid.com (Leif Roar Moldskred) - 2013-11-28 16:28 -0600
Re: Alternatives languages on the JVM: which one or is there no alternative? Silvio <silvio@internet.com> - 2013-11-29 00:03 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? Saxo <jeti789@web.de> - 2013-11-29 00:41 -0800
Re: Alternatives languages on the JVM: which one or is there no alternative? Silvio <silvio@internet.com> - 2013-11-29 12:05 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? Saxo <jeti789@web.de> - 2013-11-29 03:51 -0800
Re: Alternatives languages on the JVM: which one or is there no alternative? Silvio <silvio@internet.com> - 2013-11-29 16:44 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? Silvio <silvio@internet.com> - 2013-11-29 16:48 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? Robert Klemme <shortcutter@googlemail.com> - 2013-12-02 06:33 -0800
Re: Alternatives languages on the JVM: which one or is there no alternative? Silvio <silvio@internet.com> - 2013-12-02 15:50 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? Silvio <silvio@internet.com> - 2013-12-02 16:26 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? Robert Klemme <shortcutter@googlemail.com> - 2013-12-02 21:07 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? Silvio <silvio@internet.com> - 2013-12-02 23:33 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? markspace <markspace@nospam.nospam> - 2013-12-02 18:07 -0800
Re: Alternatives languages on the JVM: which one or is there no alternative? Silvio <silvio@internet.com> - 2013-12-03 08:59 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? Saxo <jeti789@web.de> - 2013-12-03 00:14 -0800
Re: Alternatives languages on the JVM: which one or is there no alternative? Silvio <silvio@internet.com> - 2013-12-03 09:42 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? Saxo <jeti789@web.de> - 2013-12-03 02:58 -0800
Re: Alternatives languages on the JVM: which one or is there no alternative? Martin Gregorie <martin@address-in-sig.invalid> - 2013-12-03 20:55 +0000
Re: Alternatives languages on the JVM: which one or is there no alternative? Saxo <jeti789@web.de> - 2013-12-04 00:12 -0800
Re: Alternatives languages on the JVM: which one or is there no alternative? Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-12-14 03:31 -0400
Re: Alternatives languages on the JVM: which one or is there no alternative? Martin Gregorie <martin@address-in-sig.invalid> - 2013-12-14 10:11 +0000
Re: Alternatives languages on the JVM: which one or is there no alternative? Robert Klemme <shortcutter@googlemail.com> - 2013-12-14 17:39 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? "Chris Uppal" <chris.uppal@metagnostic.REMOVE-THIS.org> - 2013-12-14 16:52 +0000
Re: Alternatives languages on the JVM: which one or is there no alternative? Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-12-14 13:47 -0400
Re: Alternatives languages on the JVM: which one or is there no alternative? Robert Klemme <shortcutter@googlemail.com> - 2013-12-14 23:55 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? Sebastian <news@seyweiler.dyndns.org> - 2013-12-04 10:39 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-12-14 03:56 -0400
Re: Alternatives languages on the JVM: which one or is there no alternative? v_borchert@despammed.com (Volker Borchert) - 2013-11-26 21:28 +0000
Re: Alternatives languages on the JVM: which one or is there no alternative? Robert Klemme <shortcutter@googlemail.com> - 2013-11-26 23:29 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? v_borchert@despammed.com (Volker Borchert) - 2013-11-27 05:13 +0000
Re: Alternatives languages on the JVM: which one or is there no alternative? Robert Klemme <shortcutter@googlemail.com> - 2013-11-27 22:57 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? v_borchert@despammed.com (Volker Borchert) - 2013-11-29 23:22 +0000
Re: Alternatives languages on the JVM: which one or is there no alternative? Robert Klemme <shortcutter@googlemail.com> - 2013-11-30 14:41 +0100
Re: Alternatives languages on the JVM: which one or is there no alternative? Joshua Cranmer 🐧 <Pidgeot18@verizon.invalid> - 2013-11-30 16:49 -0600
Re: Alternatives languages on the JVM: which one or is there no alternative? Joshua Cranmer 🐧 <Pidgeot18@verizon.invalid> - 2013-11-27 23:07 -0600
Re: Alternatives languages on the JVM: which one or is there no alternative? Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2013-11-28 23:41 +0000
Re: Alternatives languages on the JVM: which one or is there no alternative? Joshua Cranmer 🐧 <Pidgeot18@verizon.invalid> - 2013-11-29 00:08 -0600
Re: Alternatives languages on the JVM: which one or is there no alternative? Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2013-11-29 16:49 +0000
Re: Alternatives languages on the JVM: which one or is there no alternative? Joshua Cranmer 🐧 <Pidgeot18@verizon.invalid> - 2013-11-30 16:46 -0600
Re: Alternatives languages on the JVM: which one or is there no alternative? Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2014-02-14 15:36 +0000
Re: Alternatives languages on the JVM: which one or is there no alternative? v_borchert@despammed.com (Volker Borchert) - 2013-11-29 23:37 +0000
Re: Alternatives languages on the JVM: which one or is there no alternative? Roedy Green <see_website@mindprod.com.invalid> - 2013-11-28 12:50 -0800
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