My problem with doing database lookups in ActionForm.reset() is that an exception may occur and it's not as easy to handle as it when doing things within the Action class (where you can just forward things to an error.jsp).
I find that if I trap the exception, the populate method may have problems because reset() didn't complete and the controller will throw an exception to the container's handler, and if I don't trap it, the controller again handles the exception. Is this the reason you recommend not doing DB lookups in ActionForm.reset(), or are there other considerations that make it undesirable? -JT -----Original Message----- From: Craig R. McClanahan [mailto:[EMAIL PROTECTED]] Sent: Monday, September 30, 2002 8:43 AM To: Struts Users Mailing List Cc: '[EMAIL PROTECTED]' Subject: Re: SURVEY: Proper Way To Pre-populate ActionForms The struts-example app (which uses a separate action for the setup) is the method that I recommend for manually setting up an ActionForm instance, plus any other beans that need to be looked up and placed in request scope. To remind you of the relationships, the actions and the JSP page are named similarly: * editRegistration.do -- Set up the "registration.jsp" form bean * registration.do -- The input page for registration information * saveRegistration.do -- Save the new or updated registration information to the database It's fine to rely on the auto-creation of the form bean if you don't need to look up any database information (i.e. you're going to be doing a "create" type transaction), where you just make your reset() method set up all the defaults. However, if you're going to do an "edit" transaction against existing data from the database, I prefer to look that up in a setup action rather than make the reset() method have to go to the database itself. Craig McClanahan On Mon, 30 Sep 2002, Hohlen, John wrote: > Date: Mon, 30 Sep 2002 08:22:29 -0500 > From: "Hohlen, John" <[EMAIL PROTECTED]> > Reply-To: Struts Users Mailing List <[EMAIL PROTECTED]> > To: "Struts-Help (E-mail)" <[EMAIL PROTECTED]> > Cc: "'[EMAIL PROTECTED]'" <[EMAIL PROTECTED]> > Subject: SURVEY: Proper Way To Pre-populate ActionForms > > I was wondering what the overall philosophy is in the Struts Users community > in regards to pre-populating action forms? I sent a message out late last > week asking for help on how to manually instantiate and pre-populate an > action form (prior to forwarding to a JS) in Struts 1.1. That's when I > realized this may be considered bad practice. Here are some comments I > received: > > Eddie Bush: > "No, no. Actions/Forms have a contract -- the form 'will' be created. > You should not take this upon yourself. What you need to do is pre-face > the page with a 'populate' action. Expect it to be there" > > James Turner: > I can still point to cases where you need to manually pre-populate. > For example, if you have multiple forms on a single JSP page, you either > need to pre-populate the forms manually, or you'd have to daisy-chain a > bunch of actions together, each one of which was responsible for > pre-populating a single form. This seems clumsy to me. Maybe what we need > is an authoritative way (i.e., an API) to instantiate DynaForms. > > What are others doing here? BTW, if manually pre-populating an action form > is acceptable, does it make sense to create a method in the "RequestUtils" > package making this > easy to do for a DynaForm (Struts 1.1). For example (code provided by James > Turner): > > ApplicationConfig appConfig = > (ApplicationConfig)request.getAttribute(Action.APPLICATION_KEY); > FormBeanConfig formBeanConfig = > appConfig.findFormBeanConfig("myDynaActionForm"); > String beanType = formBeanConfig.getType(); > DynaActionForm bean; > DynaActionFormClass formClass = > DynaActionFormClass.createDynaActionFormClass(formBeanConfig); > return (DynaActionForm) formClass.newInstance(); > > Thanks! JOHN > > > -- > To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> > For additional commands, e-mail: <mailto:[EMAIL PROTECTED]> > > -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
