I need to set visibility or modifiable property of every component in a page using some logic specific for differents customer and I don't want that every programmer has to remember to set correctly EL Espression or something else. This is the scenario, but is a curiosity also.....i would like to go in deep to know if this kind stuff is possible to implements.
Thanks Mario -----Original Message----- From: Simon Kitching [mailto:[EMAIL PROTECTED] Sent: 27 febbraio 2007 21.53 To: MyFaces Discussion Subject: Re: Change visibility dinamically This does sound like a pretty weird scenario. You want to change the behaviour of the application but don't want to change the application? However I guess this could be done in a PhaseListener. After restore-view, look in a database (for example) to see if there are any "overrides" for the current view, and if so retrieve a set of (component-id, el-expression) values. Then walk the current component tree and for each component that has an id that matches one of the "overrides", evaluate the EL-expression and update the component's rendered state. A custom UIViewRoot component might also work.. I can't really see *why* you would want to do this, though. Seems much easier to just update the JSP/facelets file to add the rendered attribute. A system like this might make more sense for "security" reasons, ie ensure that every field that is not "authorised" for the current user is automatically not rendered. Tomahawk does have the "visibleOnUserRole" attribute for this but a PhaseListener approach also has appeal. of course this depends on being able to somehow identify the components; having the attribute on the component tag itself avoids that issue. [EMAIL PROTECTED] wrote: > Yes I know, using rendered, valueBinding and managed bean I can do it, > but to use these options I have to project the application to managed > this cases. Suppose I have developed an application and in a page I have > a textbox that, at develop design, noone supposed this component could > be hide in some situation...so the text box is always rendered. In this > case I don't have no programmatic "if" and no EL expression. How can I > hide this texbox without modify the code? I was thinking to implement a > my UIViewRoot, override the component in faces-config to force to use my > UIViewRoot and put inside my UIViewRoot all the logic.....is it > possible? Is it correct? > > -----Original Message----- > From: Mike Kienenberger [mailto:[EMAIL PROTECTED] > Sent: 27 febbraio 2007 21.23 > To: MyFaces Discussion > Subject: Re: Change visibility dinamically > > Oops. You're right, Simon. It could be set programmically. I > still think it's a bad design, but that's just my opinion. > > On 2/27/07, Simon Kitching <[EMAIL PROTECTED]> wrote: >> Not sure what you mean, Mike. >> >> Every UIComponent has a setRendered(boolean) method that can be called >> to specify whether that component is rendered or not. This method > could >> certainly be called from a PhaseListener. >> >> Note that there is a slight flaw in the design of this method in my >> opinion; the rendered property can be specified as either an EL >> expression (ie stored as a ValueBinding) or can be a literal value set >> via setRendered(). If a value-binding is used then setRendered() can >> later be used to override that; however once rendered has been set > using >> setRendered, there is no way to go back to using an EL expression. > In >> other words, once you've decided to manually control the rendered > state >> you cannot go back to using the original EL rendered expression. >> >> One way around this would be to use >> // create a ValueBinding for the expression #{true} >> setValueBinding("rendered", vb); >> rather than >> setRendered(true); >> >> Cheers, >> >> Simon >> >> Mike Kienenberger wrote: >>> You can only set the rendered property of a component from the > values >>> of a managed bean (unless you're using facelet functions or > customized >>> el resolvers). Your managed bean can call whatever java code you >>> want it to. >>> >>> If you give more specific details of what you're trying to > accomplish, >>> maybe we can help you more. >>> >>> >>> On 2/27/07, [EMAIL PROTECTED] >>> <[EMAIL PROTECTED]> wrote: >>>> >>>> >>>> >>>> I wanna change the behavior of my application changing the > visibility of >>>> some component basing of specific rules but I don't wan put this > logic >>>> in my >>>> Managed Bean but externally. May be implementing a Phase Listener > can >>>> help >>>> me to do this? In wich Phase should I set the visible property of > my >>>> components? >>>> > > > This message is for the designated recipient only and may contain privileged, proprietary, or otherwise private information. If you have received it in error, please notify the sender immediately and delete the original. Any other use of the email by you is prohibited. This message is for the designated recipient only and may contain privileged, proprietary, or otherwise private information. If you have received it in error, please notify the sender immediately and delete the original. Any other use of the email by you is prohibited.
