advice on managing exceptions / session timeouts

[henderson_mk]

Hi folks,

I'm currently using seam for a basic webapp.... but it has contstraints in that any fallovers need to be pretty. i.e. should a nullpointerexception be thrown from the code for any reason, I'd like this to forward to a standard error page that has the usual hand holding stuff... I was wondering if anyone had any thoughts on best practices for this?

I had toyed with a servlet filter but this is causing problems with the conversation context... next thought was an application wide aspect perhaps?

Hope you can help,

Thanks,

Marty

[gavin.king]

A servlet filter is the correct solution. I have no idea why this should cause any problem. Of course, you should not try to access the Seam contexts from the filter.

[henderson_mk]

thanks for the response Gavin....
my filter looks like this:

 public void doFilter(ServletRequest servletrequest,
 ServletResponse servletresponse,
 FilterChain filterchain)
 throws IOException, ServletException
 {
 HttpServletRequest httpservletrequest = (HttpServletRequest)servletrequest;
 HttpSession httpsession = httpservletrequest.getSession(false);

 try
 {
 filterchain.doFilter(servletrequest, servletresponse);
 log.info("all ok...");
 }
 catch (Throwable t)
 {
 log.info("throwable caught..");
 StringWriter sw = new StringWriter();
 PrintWriter pw = new PrintWriter(sw, true);
 t.printStackTrace(pw);
 pw.flush();
 sw.flush();
 log.error("throwable=" + t.getMessage());
 log.error("stack=" + sw.toString());

 HttpServletResponse httpservletresponse = (HttpServletResponse)servletresponse;
 ServletContext servletcontext = config.getServletContext();
 if (getRedirect(redirect))
 {
 httpservletresponse.sendRedirect(redirect);
 }
 else
 {
 RequestDispatcher requestdispatcher = servletcontext.getRequestDispatcher(redirect);
 requestdispatcher.forward(servletrequest, servletresponse);
 }
 }
 }

and the error looks like this:

java.lang.IllegalStateException: Could not start transaction
 at org.jboss.seam.jsf.SeamExtendedManagedPersistencePhaseListener.beforePhase(Unknown Source)
 at org.apache.myfaces.lifecycle.LifecycleImpl.informPhaseListenersBefore(LifecycleImpl.java:520)
 at org.apache.myfaces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:342)
 at javax.faces.webapp.FacesServlet.service(FacesServlet.java:107)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
 at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:672)
 at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:463)
 at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:398)
 at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:301)
 at org.mhenderson.turnaround.servlets.filter.GenericExceptionServletFilter.doFilter(GenericExceptionServletFilter.java:118)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
 at org.mhenderson.turnaround.servlets.filter.SessionExpiryServletFilter.doFilter(SessionExpiryServletFilter.java:99)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
 at org.apache.myfaces.component.html.util.ExtensionsFilter.doFilter(ExtensionsFilter.java:122)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
 at org.jboss.seam.servlet.SeamExceptionFilter.doFilter(Unknown Source)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
 at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:81)
 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.jboss.web.tomcat.security.CustomPrincipalValve.invoke(CustomPrincipalValve.java:39)
 at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:157)
 at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:59)
 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:856)
 at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:744)
 at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
 at org.apache.tomcat.util.net.MasterSlaveWorkerThread.run(MasterSlaveWorkerThread.java:112)
 at java.lang.Thread.run(Thread.java:595)
Caused by: javax.transaction.NotSupportedException: Transaction already active, cannot nest transactions.
 at org.jboss.tm.TxManager.begin(TxManager.java:193)
 at org.jboss.tm.usertx.client.ServerVMClientUserTransaction.begin(ServerVMClientUserTransaction.java:110)
 ... 39 more

I'm a bit confused to be honest...

[gavin.king]

Looks like you forgot to rollback the txn in your filter. Or something like that.

[henderson_mk]

ok... this may be a stupid question... (so apologies in advance)... how do I do that? Or what should I use to do that?

[gavin.king]

Have you tried/looked at SeamExceptionFilter?

[henderson_mk]

just did. Star man.
thanks very much for the pointers in the right direction! Really appreciate it.

[corzar71]

A servlet filter is the correct solution. I have no idea why this should cause any problem. Of course, you should not try to access the Seam contexts from the filter.

Hi Gavin, I took this good example to redirect erros to my custom page. Now I need to know how can I keep the exception object to show it in the error page. Of course, how you said, I cannot use seam contexts. What I have to do?