Re: Separate interface and implemenation problem..

From:
Tom Anderson <twic@urchin.earth.li>
Newsgroups:
comp.lang.java.programmer
Date:
Fri, 5 Jun 2009 00:48:17 +0100
Message-ID:
<alpine.DEB.1.10.0906050044060.21763@urchin.earth.li>
On Thu, 4 Jun 2009, Mark Space wrote:

Lew wrote:

Static methods go against the point of interfaces, since static methods
cannot be inherited. You get everything you need from static methods
in a utility (usually non-instantiable) class anyway.


As Steven picked-up on, my intention was to define a kind of interface for
static methods, not replace classes of static methods with interfaces. I
think such an static interface would be useful for various kinds of factory
patterns.

// not real code
public static interface MyFactory {
 MyObject makeObject(); // implicitly static and public
}

//...

public class MyObject implements static MyFactory {

 public static MyObject makeObject() {
   ...
 }
}

Or something like that...


This is a perennial problem. Here's what i came up with five years ago:

http://c2.com/cgi/wiki?ConstructorObject

Thinking about it, though, another solution would just be to load a
factory class, Class.newInstance it, and then get instances of the class
of interest from it, without ever addressing the class of interest
directly.

tom

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