Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > comp.lang.java.programmer > #35895
| Path | csiph.com!weretis.net!feeder4.news.weretis.net!news.albasani.net!.POSTED!not-for-mail |
|---|---|
| From | Sebastian <nowhere@nirvana.org> |
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: "implements" does not mean "implements" |
| Date | Sun, 13 Nov 2016 22:30:58 +0100 |
| Organization | albasani.net |
| Lines | 34 |
| Message-ID | <o0am2g$7ji$1@news.albasani.net> (permalink) |
| References | <implements-20161110014035@ram.dialup.fu-berlin.de> <o03914$18dp$1@gioia.aioe.org> <o06qgq$ec$1@news.albasani.net> <o076o0$11rm$1@gioia.aioe.org> |
| Mime-Version | 1.0 |
| Content-Type | text/plain; charset=windows-1252; format=flowed |
| Content-Transfer-Encoding | 8bit |
| X-Trace | news.albasani.net fWHjtOFp+TJhqOiqyXKjisIu7hD7AmoBTFSUJQnj1+xCEVzdxoj8N4yfRpIIogfCnEZAM2OsHXNvQ/8lLbe0QA== |
| NNTP-Posting-Date | Sun, 13 Nov 2016 21:30:56 +0000 (UTC) |
| Injection-Info | news.albasani.net; logging-data="B0+GA/CMCtQkctEbZD7kXBSv4mX5XHQfLHpfQBS8KofeoU4ep0kNBwVgEzgGauOjgVVgEASEJ32VIW7YvhfjFSAcjmcQjVgSx8wewU745aQj94Dhx1vvPqPyDnvEAOX3"; mail-complaints-to="abuse@albasani.net" |
| User-Agent | Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 |
| In-Reply-To | <o076o0$11rm$1@gioia.aioe.org> |
| Cancel-Lock | sha1:tkOPhVcqlekm7A/XdhMhyb/p/sM= |
| Xref | csiph.com comp.lang.java.programmer:35895 |
Show key headers only | View raw
Am 12.11.2016 um 14:50 schrieb Arne Vajhøj:
> On 11/12/2016 5:22 AM, Sebastian wrote:
>> I like to say that interfaces specify behaviors of objects, not
>> properties of classes. Saying that C implements A amounts to saying that
>> any o that is an instance of C behaves like an A. It has nothing to do
>> with what methods get implemented in C.
>
> Behavior of objects and properties of classes should have some
> relationship.
>
> But just realized something that I think matches well
> with you way of thinking.
>
> interface A { void m(); }
>
> abstract class C implements A { }
>
> class Foobar extends C { public void m() { } }
>
> actually compiles - it is not necessary to have an abstract m in C.
>
> Arne
yes, indeed, the methods are already abstract in C by virtue of the
interface.
By the way, a typical use of such an idiom may be where C is some
abstract class that offers some help in implementing A, or adds related
behavior, so that C wouldn't really be an abstraction in its own right,
but would exist only for purposes of code-reuse. In Java 8, such usage
could be replaced with default methods in interfaces.
-- Sebastian
Back to comp.lang.java.programmer | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
Re: "implements" does not mean "implements" Arne Vajhøj <arne@vajhoej.dk> - 2016-11-10 21:05 -0500
Re: "implements" does not mean "implements" Sebastian <nowhere@nirvana.org> - 2016-11-12 11:22 +0100
Re: "implements" does not mean "implements" Arne Vajhøj <arne@vajhoej.dk> - 2016-11-12 08:50 -0500
Re: "implements" does not mean "implements" Sebastian <nowhere@nirvana.org> - 2016-11-13 22:30 +0100
Re: "implements" does not mean "implements" Arne Vajhøj <arne@vajhoej.dk> - 2016-11-14 19:48 -0500
csiph-web