--- Michael Heuer <[EMAIL PROTECTED]> wrote: > On Tue, 29 Jul 2003, David Graham wrote: > > > --- Arun Thomas <[EMAIL PROTECTED]> wrote: > > > Hmmm.... From the last three notes - I think I understand clearly > the > > > motivation for requiring the public no-arg constructor, but I still > > > don't understand the reasoning behind the need for avoiding final. > The > > > only reason I can see (with possibly poor vision) is to allow access > to > > > the methods of the utility class plus additional specific methods > with > > > a handle on only one class object or utility instance (of the > subclass > > > utility). This seems to me to be very poor design if such a > constraint > > > exists. Can anyone see any other value to extending utility classes > > > with entirely static methods? > > > > Because static methods can't be overridden you may as well declare > them > > final. However, static methods are truly evil. As soon as you think > no > > one will ever need to override the behavior, some user will come along > > with a need to do so. This happened in Struts and now we're replacing > all > > the static methods with Singleton classes with instance methods. > > Is the struts mailing list the best place to go archive-digging on this > topic? At first glance I don't really see the `need to override > behavior' > argument -- if a user doesn't like the way a static method is > implemented, can't they just implement their own in a separate class?
Certainly, but that's not a very friendly approach for a reusable framework of classes to take. David > > michael > > > > > > David > > > > > > > > Cheers, > > > -AMT > > > > > > -----Original Message----- > > > From: David Graham [mailto:[EMAIL PROTECTED] > > > Sent: Tuesday, July 29, 2003 11:44 AM > > > To: Jakarta Commons Developers List > > > Subject: RE: [io][vote] FileUtils: decision on style > > > > > > > > > --- Arun Thomas <[EMAIL PROTECTED]> wrote: > > > > Can someone expound on this "lesson"? The Developers Guide > mentions > > > > neither the rule that "final" should be avoided, nor the rule that > a > > > > public constructor is required. I'd love to know the reasoning - > is > > > > there some reason that actually derives from the constraints of > lang, > > > > or is it due to constraints on how other systems use lang? I'm > > > > particularly confounded by why the use of final would be a > problem. > > > > > > Marking a class as final prevents subclassing which is an > > > extraordinarily bad idea in generally available framework classes. > This > > > also goes for methods. Classes without default constructors are not > > > JavaBeans and thus cannot be dynamically created and used in certain > > > environments. > > > > > > David > > > > > > > > > > > Cheers, > > > > -AMT > > > > > > > > -----Original Message----- > > > > From: Henri Yandell [mailto:[EMAIL PROTECTED] > > > > Sent: Tuesday, July 29, 2003 5:55 AM > > > > To: Jakarta Commons Developers List > > > > Subject: Re: [io][vote] FileUtils: decision on style > > > > > > > > > > > > > > > > > > > > On Tue, 29 Jul 2003 [EMAIL PROTECTED] wrote: > > > > > > > > > Hey thanks for the heads up! > > > > > > > > > > being one of the original authors/contributor of this class, I > do > > > > > have > > > > > > > > > some comments (mostly in favour of your proposal)... > > > > > > > > > > 1rst: you seem to have added a private constructor to prevent > > > > > instantiation, which hurts usage as in velocity, where you need > an > > > > > instance of a class to allow the introspection to work. I'm -1 > for > > > > > that change in CVS. > > > > > > > > Yep. This is a Lang-lesson. Have an empty constructor in every > 'Utils' > > > > > > > class which mentions in a javadoc that this is not intended to be > > > > used: > > > > > > > > /** > > > > * <p><code>ObjectUtils</code> instances should NOT be > constructed > > > > > > > in > > > > * standard programming. Instead, the class should be used as > > > > * <code>ObjectUtils.defaultIfNull("a","b");</code>.</p> > > > > * > > > > * <p>This constructor is public to permit tools that require > a > > > > JavaBean instance > > > > * to operate.</p> > > > > */ > > > > > > > > Also worth looking at and maybe adopting the relatively simple: > > > > DEVELOPERS-GUIDE.html in Lang. Mainly it just outlines the > XxxUtils > > > > philosophy. > > > > > > > > Also don't make XxxUtils a final class. > > > > > > > > Hen > > > > > > > > > > > > > --------------------------------------------------------------------- > > > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > > > For additional commands, e-mail: > [EMAIL PROTECTED] > > > > > > > > > > > > > --------------------------------------------------------------------- > > > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > > > For additional commands, e-mail: > [EMAIL PROTECTED] > > > > > > > > > > > > > __________________________________ > > > Do you Yahoo!? > > > Yahoo! SiteBuilder - Free, easy-to-use web site design software > > > http://sitebuilder.yahoo.com > > > > > > > --------------------------------------------------------------------- > > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > > > > > > --------------------------------------------------------------------- > > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > > > > > __________________________________ > > Do you Yahoo!? > > Yahoo! SiteBuilder - Free, easy-to-use web site design software > > http://sitebuilder.yahoo.com > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > __________________________________ Do you Yahoo!? Yahoo! SiteBuilder - Free, easy-to-use web site design software http://sitebuilder.yahoo.com --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
