Re: Force a class to have certain static methods

From:

Lew <lew@lewscanon.com>

Newsgroups:

comp.lang.java.programmer

Date:

Mon, 05 Nov 2007 09:42:03 -0500

Message-ID:

<ppmdnUOKTMImtrLanZ2dnUVZ_oKhnZ2d@comcast.com>

Chris wrote:

How do I force a class to have certain static methods?

Make them instance methods.

Here's the problem. Our system has certain pluggable classes. To make
a new implementation of such a class, you just have it implement a
certain interface.

Nice, clean design.

I want to have these classes have certain static methods like
getName() and getDescription() that just return constants. The
trouble is, you can't put static methods in an interface. You also
can't have static abstract methods.

Make them instance methods.

Mike Schilling wrote:

1. Via an instance, and
2. By reflection.

I'm ruling out 1 since you're trying to avoid creating an instance, so that
leaves 2..

Of course, if "efficiency" is your goal, then using reflection in lieu of
instantiation is not going to help you. /Au contraire/.

The overhead of creating instances is not large, and the need for polymorphism
suggests that you go right ahead and declare an interface, and use instance
methods to implement it. Then you'll have a nice clean design. If your
implementations deliver compile-time constants via the methods, they will be
inlined and your so-called "overhead" will vanish entirely.

--
Lew