Why calling ValidationDelegate.record() at pageBeginRender result in NullPointerException?

[Raymond Chan <ra...@hket.com>]

I need to record and display an error message on a page as a result of
another page's form submission error. More specifically, there're the
Registration page and the RegistrationConfirm page. The Registration page
checks all input errors except unavailable login name, then activate the
RegistrationConfirm page to display the user input registration info with 2
buttons to either Confirm or Back. If user clicks the Confirm button then
the RegistrationConfirm page goes ahead to really try to create a user
account record in the db and if the login name user chooses already exists
in the db then the RegistrationConfirm page would set a declared ErrorMsg
property of the Registration page and activate it. So I put code in the
pageBeginRender method to check if that property is not null then use the
ValidationDelegate to record and display the error msg when it displays.

What's wrong with it?

Please see the error report below:
############################################################################
###
An exception has occurred.
You may continue by restarting the session.
org.apache.tapestry.ApplicationRuntimeException

component:com.mycompany.Registration$Enhance_16@1a01e8a[Registration]
location:context:/WEB-INF/Registration.page, line 8, column 62

java.lang.NullPointerException

Stack Trace:
org.apache.tapestry.valid.ValidationDelegate.getComponentTracking(Validation
Delegate.java:121)
org.apache.tapestry.valid.ValidationDelegate.findCurrentTracking(ValidationD
elegate.java:276)
org.apache.tapestry.valid.ValidationDelegate.record(ValidationDelegate.java:
229)
org.apache.tapestry.valid.ValidationDelegate.record(ValidationDelegate.java:
207)
com.mycompany.Registration.pageBeginRender(Registration.java:34)
org.apache.tapestry.AbstractPage.firePageBeginRender(AbstractPage.java:463)
org.apache.tapestry.AbstractPage.renderPage(AbstractPage.java:293)
org.apache.tapestry.engine.RequestCycle.renderPage(RequestCycle.java:371)
org.apache.tapestry.engine.AbstractEngine.renderResponse(AbstractEngine.java
:732)
org.apache.tapestry.engine.DirectService.service(DirectService.java:174)
org.apache.tapestry.engine.AbstractEngine.service(AbstractEngine.java:872)
org.apache.tapestry.ApplicationServlet.doService(ApplicationServlet.java:197
)
org.apache.tapestry.ApplicationServlet.doPost(ApplicationServlet.java:326)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Application
FilterChain.java:237)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterCh
ain.java:157)
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.ja
va:214)
org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContex
t.java:104)
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContext
Valve.java:198)
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.ja
va:152)
org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContex
t.java:104)
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137
)
org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContex
t.java:104)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117
)
org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContex
t.java:102)
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java
:109)
org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContex
t.java:104)
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:793)
org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConne
ction(Http11Protocol.java:702)
org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:571)
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.jav
a:644)
java.lang.Thread.run(Thread.java:534)


---------------------------------------------------------------------
To unsubscribe, e-mail: tapestry-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: tapestry-user-help@jakarta.apache.org