Re: Failing to take control of navigation

[Calvin Hill]

Alright, I need to clear up issue with what I wrote below.  First, it  
is correct that Shale remoting will get you to a function on a  
managed bean from a get request.  Though, since it was not part of  
the lifecycle, there will not be a response and you will end up with  
a blank page (at least I did).  The email from Volker that gave the  
wiki link, that page has an example of getting the lifecycle and  
rendering the facesContext.  This is what I did so that response went  
to the correct view.  Sorry for any confusion.

Thanks,
Calvin Hill
return Programmer.someType()


On Dec 27, 2006, at 4:33 PM, Calvin Hill wrote:

Ok, you are trying to do a request (some form of permanent link)  
that will access another JSF page, right?  Of course, this link  
could be from a static html page, too.  Well, we had the same  
problem.  MyFaces has one way of doing it that is found on their  
Wiki (can't find it) using a Servlet.  What we ended up doing is  
using Shale remoting.  You will need to add shale-application,  
shale-core, shale-remoting to your project.  Then open the web.xml  
file and add the following to the filter section;
        <filter>
                <filter-name>shale</filter-name>
        	<filter- 
class>org.apache.shale.application.faces.ShaleApplicationFilter</ 
filter-class>
        </filter>

        <filter-mapping>
                <filter-name>shale</filter-name>
                <url-pattern>*.jsf</url-pattern>
        </filter-mapping>

Now add to the context-param section;
        <context-param>
                <param-name>
                        org.apache.shale.remoting.DYNAMIC_RESOURCES
                </param-name>
                <param-value>
            		/dynamic/ 
*:org.apache.shale.remoting.impl.MethodBindingProcessor
                </param-value>
        </context-param>

Now if you have a class called IceCream and it is in the faces- 
config.xml file being managed as icecreamBean; then from the page  
you want to add a permlink add "dynamic/icecreamBean/ 
mixMe.jsf" (dynamic refers to what was added in the web.xml  
file).   mixMe is a function within IceCream.  Now, I am just  
learning Shale and have had help (lots).  So don't think that I  
came up with this all on my own ;).   So now your function can do  
what it needs and return an action that can be used for  
navigation.  If this is not it, I do hope someone else is able to  
assist.

Calvin Hill
return Programmer.someType()




On Dec 27, 2006, at 1:25 PM, yuvalgo wrote:


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.

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