aaaaah, ok, well thanks, that was rather illuminating :) thanks a thousand Julian
> --- Ursprüngliche Nachricht --- > Von: "Leon Rosenberg" <[EMAIL PROTECTED]> > An: "Struts Users Mailing List" <user@struts.apache.org> > Betreff: Re: ActionForm Stringvariables > Datum: Thu, 16 Mar 2006 14:19:41 +0100 > > well, two reasons, the practical one: > checks for null are annoying, and people tend to lazily forget them. > > the more theoretical reason, is that null is not a truly OO concept > (at least according to some authors), and you should use a NullObject > concept (being of same type as your normal Object expected by the > code) instead. In opposite to the NullObject the null misses important > semantics about the objects structure. > > Using null for string initialization is an entry point to bad > practices, absolutely 'bad' are following practices: > > putting null in lists/maps > transporting null over network (rmi,corba,soap etc) > putting null beans in scopes (not sure this works, but should never > bin tried :-)) > returning null from functions instead of more meaningfull reply: > For example getUser(String userName) should throw a > NotSuchUserException if there is no corresponding User object instead > of returning null. There are very few scenarios (mostly high > performance, where null is actually expected - i.e. caches) where this > rule can be broken. > > I think you can find more examples in a good pattern book :-) > > HTH > Leon > > > On 3/16/06, manny Calaverra <[EMAIL PROTECTED]> wrote: > > hi Leon, > > > > is this rule because of the NullPointerException you get when, for > example > > you check the Strings ".length()" or is there (also) another reason for > this > > practice? > > > > thanks in advance > > Julian > > > > > --- Ursprüngliche Nachricht --- > > > Von: "Leon Rosenberg" <[EMAIL PROTECTED]> > > > An: "Struts Users Mailing List" <user@struts.apache.org> > > > Betreff: Re: ActionForm Stringvariables > > > Datum: Thu, 16 Mar 2006 11:06:50 +0100 > > > > > > 1. The general rule is: never use null. > > > 2. The specific rule for your application must be given by your > > > application, but in doubt the general rule applies. > > > > > > regards > > > leon > > > > > > On 3/16/06, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: > > > > Hi there, > > > > > > > > I'm a newbie to struts and I have a question concerning ActionForms. > > > > What's more clever: to initialize the String-parameters with "null" > or > > > with > > > > "" (empty strings)? > > > > > > > > thx & ciao 4 now > > > > Julian > > > > > > > > > > > > -- > > > > "Feel free" mit GMX FreeMail! > > > > Monat für Monat 10 FreeSMS inklusive! http://www.gmx.net > > > > > > > > > --------------------------------------------------------------------- > > > > 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] > > > > > > > -- > > Echte DSL-Flatrate dauerhaft für 0,- Euro*! > > "Feel free" mit GMX DSL! http://www.gmx.net/de/go/dsl > > > > --------------------------------------------------------------------- > > 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] > -- Echte DSL-Flatrate dauerhaft für 0,- Euro*! "Feel free" mit GMX DSL! http://www.gmx.net/de/go/dsl --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
