I agree. Shale would be my recommendation also. sean
On Sat, 12 Mar 2005 08:50:12 +0100, Matthias Wessendorf <[EMAIL PROTECTED]> wrote: > Yeah, > > Shale is indeed a nice enhancement for use cases like that. > init() is much *clearer* than defining stuff inside a constructor. > > -Matthias > > [EMAIL PROTECTED] wrote: > > You might take a look at Shale. It addresses this problem by defining a > > ViewController interfaces that defines extra lifecycle methods. > > init() > > destroy() > > preprocess() > > prerender() > > > > The ViewController is a managed bean that implements this interface. There > > is also an abstract class that you can inherit from, AbstractViewController. > > > > There is an assumed mapping between the managed beans name, the view id and > > the ViewController instance. It uses a filter and a phase listener to > > invoke these callback methods to a managed bean/ ViewController. > > > > It's pretty cool, http://wiki.apache.org/struts/StrutsShale > > > > Gary > > > > > > > > > >>Sure. Lazy initialization is a good pattern to follow, but if you have a > >>lot of getters using the same data it can be ugly to put checks in a lot > >>of different places. If it's just the one property, then lazy > >>initialization is definitely the way to go. > >> > >>It'd be nice if a bean could optionally implement some managed bean > >>interface and there'd be onInitialize() method that would get called > >>automatically if bean so wished (i.e. implements the interface). The > >>same approach could be used for a lot of other cases as well. > >> > >>Kalle > >> > >> > >>>-----Original Message----- > >>>From: David Gadbois [mailto:[EMAIL PROTECTED] > >>>Sent: Friday, March 11, 2005 3:31 PM > >>>To: MyFaces Discussion > >>>Subject: Re: How to execute bean method before JSF page is loaded? > >>> > >>>The pattern I have been using for this sort of thing it to > >>>have the value accessor in the bean check to see if the data > >>>has been retrieved and, if not, sets the value up. E.g., > >>> > >>>public class SomeBean { > >>> private Object value = null; > >>> > >>> public Object getValue() { > >>> if (value == null) { > >>> // Initialize value > >>> } > >>> return value; > >>> } > >>> > >>> public void setValue(Object value) { > >>> this.value = value; > >>> } > >>>} > >>> > >>>The data table then accesses the value through the getter: > >>> > >>><h:dataTable var="item" value="#{someBean.value}"> > >>> > >>>You could use a PhaseListener on the Render Response phase > >>>(and JSF 1.2 will have listeners that can be more > >>>conveniently attached to a particular view), but then you may > >>>run into problems if some other view logic needs to access > >>>the value in a prior phase. For this reason, I have found > >>>most recommendation for using a PhaseListener to be wrong-headed. > >>> > >>>--David Gadbois > >>> > >>> > >>>Jonathan Eric Miller wrote: > >>> > >>>>Does anyone know if there is a recommended way to have a > >>> > >>>bean method > >>> > >>>>executed before a JSF page is loaded? For example, I have a > >>> > >>>page with > >>> > >>>>a h:dataTable in it. What I want to do is make it so that > >>> > >>>when a user > >>> > >>>>brings up the page directly (by entering the URL in the > >>> > >>>browser text > >>> > >>>>box rather than as the result of submitting a form), a bean > >>> > >>>method is > >>> > >>>>executed which does a query to a database. I want the bean to be > >>>>populated before the page is rendered. Currently, I'm doing > >>> > >>>this using > >>> > >>>>a servlet filter. However, one problem with this is that > >>> > >>>Faces isn't > >>> > >>>>initialized at this point. This isn't a big issue, but, one > >>> > >>>issue that > >>> > >>>>I ran into is that I was using a managed bean and that bean > >>> > >>>might not > >>> > >>>>have been created by Faces when the filter executes. So, I put some > >>>>code in to test if the bean is null or not and it creates it if > >>>>necessary. I'm wondering if there is a more recommended way > >>> > >>>to do this > >>> > >>>>within the context of Faces itself. i.e. maybe using a listener or > >>>>something? Note, I only want the code to execute for a > >>> > >>>specific page. > >>> > >>>>It seems like there should be some kind of onInit() method > >>> > >>>that could > >>> > >>>>be overriden to perform initialization before a page is > >>> > >>>renderered... > >>> > >>>>I don't know much about ASP.NET, but, I think it allows you to do > >>>>something like this. I guess I could use a scriptlet in the > >>> > >>>JSP to do it. > >>> > >>>>Jon > >>>> > >>> > >>> > > >
