Hi Calvin,
I am able to get to the filter again, but there is this myfaces
nullpointerexception problem.
This is really strange.
Can anyone think of another elegant way of implementing permalinks with jsf?
Thanks.
Calvin Hill-2 wrote:
>
> Hello,
>
> I have had a similar problem but not using JSF. I was using a home
> grown MVC application. The problem I experienced was doing a request
> using a specific URI. The URI was like so "webapp/somePage.jsp". I
> was able to fix it by changing it to "/webapp/somePage.jsp". The
> first time you can get to that page just fine. But any subsequent
> time you could not. I don't know if these are two entirely different
> problems that cause the same effect or what.
>
> The next question I would ask is, on a refresh or clicking the href a
> second time are you able to step through your servlet filter again?
> Was there something in request scope on the first click but when you
> do a refresh or the href click, that something is no longer there?
> You are dying on the JSF page you were forward too; so I bet you are
> getting to the filter.
>
> Calvin Hill
> return Programmer.someType()
>
>
>
>
> On Dec 27, 2006, at 7:36 AM, yuvalgo wrote:
>
>>
>> Hi,
>> Im trying to take control of the navigation.
>> let me explain:
>> I wish to have my own piece of code to parse the request URI and
>> control the
>> navigation to the next JSF page.
>> This functionality is desired for accomplishing a permalinks scheme
>> of some
>> sort.
>> For example
>>
>> The link root/yuval/yuvals_stuff should cause the following to happen:
>>
>> - I parse the request with a servlet filter and know that we need
>> to load
>> some data for yuval.
>> - I use a ViewHandler to load the data (it delegates the call to some
>> service that gets the data from the database)
>> - I now forward the user to a known jsf page that is bounded with the
>> viehandler and presents yuval's stuff .
>>
>> Actually, the first time i try to use the code, the navigation goes
>> well.
>> But right after refresh or calling the same url again I get an
>> exception.
>> The code and the exception are provided here:
>>
>>
>> Here is what i do inside a servlet filter (I also tried to put this
>> code
>> inside the faces servlet, just for testing):
>>
>> <code>
>> FacesContext fc = FacesUtils.getFacesContext(req, res);
>>
>> String action = "#{viewPollViewHandler.go2}";
>>
>> javax.faces.application.Application application = fc.getApplication();
>> MethodBinding mb =
>> application.createMethodBinding("#{viewPollViewHandler.go2}",null);
>> String outcome = (String)mb.invoke(fc, null);
>>
>> String fromAction = mb.getExpressionString();
>> NavigationHandler navigationHandler =
>> application.getNavigationHandler();
>> navigationHandler.handleNavigation(fc, fromAction, outcome);
>> String viewId = fc.getViewRoot().getViewId();
>> UIViewRoot view = fc.getApplication().getViewHandler().createView(fc,
>> viewId);
>> view.setViewId(viewId);
>> fc.setViewRoot(view);
>>
>> fc.getExternalContext().dispatch(viewId);
>> fc.responseComplete();
>> </code>
>>
>> Explanation:
>>
>> First we try to get the FacesContext, using the current request and
>> response
>> objects. Now we know what action we want to invoke on what
>> ViewHandler, so
>> we go ahead and make a method binding for this method through the JSF
>> Application context. Now we invoke the method and get the outcome
>> String
>> from it. Till now everything seems to work ok – we get the
>> ViewHandler's
>> method invoked correctly and we get the proper outcome String from it.
>> This means the ViewHandler is now populated with our needed data,
>> so all we
>> have left to do is go to the presentation page that uses this
>> ViewHandler.
>> We use JSF's NavigationHandler to navigate as usual, giving it a
>> "fromAction" and an outcome. Now we want the name of the page for this
>> navigation, so we get the view id from the FacesContext. The view
>> id is
>> correct and points to the next page as states in the faces-
>> navigation.xml,
>> so we set it as the new view root and try to "dispatch()" (which is
>> the same
>> as "forward()") to it.
>> The result seems sufficient, as we get to the next page and all the
>> data is
>> presented correctly (sometimes, in IE only we experienced some
>> javascript
>> errors that were unknown). The big problem occurs when trying to hit
>> "REFRESH" or clicking back and then trying the original href link
>> again. We
>> suddenly get a NullPointerException that occurred in the "getValue
>> ()" method
>> of JSF's getValueBinding()".
>>
>> Can anyone contribute?
>>
>> Thank in advance!
>> Yuval.
>>
>> --
>> View this message in context: http://www.nabble.com/Failing-to-take-
>> control-of-navigation-tf2886114.html#a8062889
>> Sent from the MyFaces - Users mailing list archive at Nabble.com.
>>
>
>
>
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