hey, lot of thanks, the state field was really null because the parameters were passed to the constructor but I never saved the value...
By the reason I am a novice in tapestry, I had searched it everywhere but not in that simple way... Greetings, Michael Wölm -----Ursprüngliche Nachricht----- Von: Steve Shucker [mailto:[EMAIL PROTECTED] Gesendet: Dienstag, 12. September 2006 16:03 An: Tapestry users Betreff: Re: WG: Question: Can not get access to object fields (Null Pointer Exception) pls pls help! As a general rule, it's safer to put the literal first in statements like this: "admin".equals(user.getState()) If anyone wants to say that it looks/reads a bit funny, I'll agree. It's an odd syntax, but it protects you from NPEs. -Steve Martin Strand wrote: > Well, if you get a NPE on this line: > >>> user.getState().equals("admin") >>> > then either "user" or "getState()" is null, right? > And, since "user" is definitely not null, your private String "state" is obviously null. > > Perhaps you should add something like this: > >>> private String state = "initial state"; >>> > > > Martin > > On Tue, 12 Sep 2006 15:52:25 +0200, Michael Wölm <[EMAIL PROTECTED]> wrote: > > >> Hi, >> >> Sadly, nobody have helped me with my problem. I dont know why. Am I too noob >> or is my question incomprehensible? I would be pleased, if anybody could >> give me an advice for my problem. >> >> Greettings from Germany, >> Michael Wölm >> >> Original message is under this. >> >> -----Ursprüngliche Nachricht----- >> Von: m-woelm [mailto:[EMAIL PROTECTED] >> Gesendet: Sonntag, 10. September 2006 16:13 >> An: 'Tapestry users' >> Betreff: Question: Can not get access to object fields (Null Pointer >> Exception) >> >> Hi, >> >> I hope anybody could explain me why I get a Null Pointer Exception, if I >> want to get access to a field of an object. My method is similar to the >> eshop-project of the book Enjoying web dev with Tapestry. >> >> I tried to change the Listener-method onLogin as follows: >> >> public void onLogin(IRequestCycle cycle) { >> >> try { >> >> User user = Users.getKnownUsers().getUser(email,password); >> >> getUser().copyFrom(user); >> >> if (user.getState().equals("admin")) >> cycle.activate("Admin_Konsole"); >> >> else cycle.activate("User_Konsole"); >> >> } catch (AuthenticationException e) { >> >> ValidationDelegate delegate = getDelegate(); >> >> delegate.setFormComponent(null); >> >> delegate.record("Login failed", null); >> >> } >> >> } >> >> >> Now I get an exception at point (user.getState().equals(admin)). >> >> But why? user was set to the login-user two lines before? Why I cant get >> the field: private String state which I have set in User.class: >> >> >> private String state; >> >> public String getState() { >> >> return this.state; >> >> } >> >> >> Thx ahead! >> >> Michael Wölm >> >> >> <mailto:[EMAIL PROTECTED]> [EMAIL PROTECTED] >> >> Public Key: <http://gsg.ath.cx/~phoenix/downloads/MyPublicKey.asc> >> href="http://gsg.ath.cx/~phoenix/downloads/MyPublicKey.asc >> >> >> >> >> >> --------------------------------------------------------------------- >> 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] > > > --------------------------------------------------------------------- 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]
