Tiles works with jsf but....

Question

Hi guys,
i've a jsf application and i've tried to improve its layout with Tiles of Struts and everythings work,infact each page has its layout fixed.
I've used one header,one footer,one left menu(for quickly navigation and language selection and personal content of each page.
My question is:
if i navigate throught my application it's ok,when i use quickly navigation on left menu it's ok.
The problem is when i click on buttons that performs not only navigation,but also java logic,i've this exception (but the operation requested,as insert in database,delete etc...are done!!!!)
GRAVE: Servlet.service() for servlet Faces Servlet threw exception
java.lang.NullPointerException
     at giu.NavigationManager.handleNavigation(NavigationManager.java:23)
     at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:89)
     at javax.faces.component.UICommand.broadcast(UICommand.java:312)
     at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:267)
     at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:381)
     at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:75)
     at com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:200)
     at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:90)
     at javax.faces.webapp.FacesServlet.service(FacesServlet.java:197)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
     at org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:144)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
     at giu.AuthorizationFilter.doFilter(AuthorizationFilter.java:61)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
     at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
     at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
     at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
     at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
     at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
     at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
     at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
     at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
     at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
     at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
     at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
     at java.lang.Thread.run(Unknown Source)i've used this NavigationManager
package giu;
import javax.faces.application.NavigationHandler;
import javax.faces.context.FacesContext;
public class NavigationManager extends NavigationHandler {
     final String menuId ="@mainMenu";
     NavigationHandler _base;
     public NavigationManager (NavigationHandler base) {
          super();
          _base = base;
     public void handleNavigation(FacesContext fc, String actionMethod, String action) {
          int atPosition = action.indexOf(menuId);
          if (atPosition < 0) {
               _base.handleNavigation(fc, actionMethod, action);
          } else {
               String viewId = fc.getViewRoot().getViewId();
               fc.getViewRoot().setViewId(menuId);
               String newAction = action.substring(0, atPosition);
               _base.handleNavigation(fc, actionMethod, newAction);
}that comes from a jsf-tiles example downloaded from core Java server faces book..i'vent understood too well this navigation,can someone help me to understand it and solve my exception??
Thanks very much....(i use exadel studio pro 4,jsf 1.1.0.1,servlet 2.3 and tiles from struts 1.1)

Answer 1

giubat: I've stuggled with getting Tiles to work correctly with JSF.
If your not to far into your project, I strongly recommend Facelets, it is very simple to include other JSF files and the syntax is XML formatted which allows Exadel Studio 4.0 to check your pages.
You'll need to change you actual page extension to .xhtml, which Exadel Studio handles nicely...
Tiles is just a waste of time when combined with JSF...