[jboss-user] [JBoss Seam] - exception when using ScopeType.CONVERSATION and h:panelGrid

[charles.crouch@jboss.com]

I've got the following dummy app based on the numberGuess example (Seam 1.1GA, JSF 1.2RI, Facelets):

.xhtml

...
  | <h:panelGrid binding="#{numberGuess.dynamicPanelGrid}" />
  |    
  | Your guess:
  | <h:inputText value="#{numberGuess.currentGuess}" id="guess" required="true"/>
  | 
  | <h:commandButton value="Guess" action="#{numberGuess.testAction}"/>
  | ...

.java

@Name("numberGuess")
  | public class NumberGuess {
  | ...
  |    private Integer currentGuess;
  |    private HtmlPanelGrid grid;
  | 
  |    @Create
  |    public void begin()
  |    {
  |       log.info("Entering begin()");
  |    }
  | 
  |    public void setCurrentGuess(Integer guess)
  |    {
  |       this.currentGuess = guess;
  |    }
  | 
  |    public Integer getCurrentGuess()
  |    {
  |       return currentGuess;
  |    }
  | 
  |    public String testAction() {
  |       currentGuess = currentGuess + 1;
  |       return null;
  |    }
  | 
  |    
  | 
  |   public HtmlPanelGrid getDynamicPanelGrid() {
  |     if (grid == null) {
  |       Application app = FacesContext.getCurrentInstance().getApplication();
  |       grid = (HtmlPanelGrid) app.createComponent(HtmlPanelGrid.COMPONENT_TYPE);
  | 
  |       HtmlOutputText text = (HtmlOutputText) app.createComponent(HtmlOutputText.COMPONENT_TYPE);
  |       text.setValue("Hello World");
  |       grid.getChildren().add(text);
  |     }
  | 
  |     return grid;
  |   }
  | 
  |    public void setDynamicPanelGrid(HtmlPanelGrid aGrid){
  |       grid = aGrid;
  |    }
  |   ...
  |   
  
  
So far so good, everything works great when I render the page the first time: I get the Hello World message and an empty textbox. Entering a number in the box and hitting Guess refreshes the page with Hello World and number+1 displayed, exactly as expected.

Now I want to make the scope of this numberGuess bean to be Conversational so I don't get a new instance each time. So I add @Scope

  | @Name("numberGuess")
  | @Scope(ScopeType.CONVERSATION)
  | public class NumberGuess {
  | 

and 

@Begin

 @Create
  |  @Begin
  |    public void begin()
  |    {
  |    

Now when I render the page the first time again, everything is great as before. Enter a number and hit Guess, before it gets to any of my breakpoints on the java side, it goes bang...


  | HTTP Status 500 - 
  | 
  | --------------------------------------------------------------------------------
  | 
  | type Exception report
  | 
  | message 
  | 
  | description The server encountered an internal error () that prevented it from fulfilling this request.
  | 
  | exception 
  | 
  | javax.servlet.ServletException: /numberGuess.xhtml @18,66 binding="#{numberGuess.dynamicPanelGrid}": Target Unreachable, identifier 'numberGuess' resolved to null
  | 	org.jboss.seam.servlet.SeamExceptionFilter.doFilter(SeamExceptionFilter.java:61)
  | 	org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
  | 
  | 
  | root cause 
  | 
  | javax.servlet.ServletException: /numberGuess.xhtml @18,66 binding="#{numberGuess.dynamicPanelGrid}": Target Unreachable, identifier 'numberGuess' resolved to null
  | 	javax.faces.webapp.FacesServlet.service(FacesServlet.java:256)
  | 	org.jboss.seam.servlet.SeamRedirectFilter.doFilter(SeamRedirectFilter.java:32)
  | 	org.jboss.seam.servlet.SeamExceptionFilter.doFilter(SeamExceptionFilter.java:46)
  | 	org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
  | 
  | 
  | root cause 
  | 
  | javax.el.PropertyNotFoundException: /numberGuess.xhtml @18,66 binding="#{numberGuess.dynamicPanelGrid}": Target Unreachable, identifier 'numberGuess' resolved to null
  | 	com.sun.facelets.el.TagValueExpression.setValue(TagValueExpression.java:95)
  | 	com.sun.faces.lifecycle.RestoreViewPhase.doPerComponentActions(RestoreViewPhase.java:258)
  | 	com.sun.faces.lifecycle.RestoreViewPhase.doPerComponentActions(RestoreViewPhase.java:263)
  | 	com.sun.faces.lifecycle.RestoreViewPhase.doPerComponentActions(RestoreViewPhase.java:263)
  | 	com.sun.faces.lifecycle.RestoreViewPhase.execute(RestoreViewPhase.java:225)
  | 	com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:244)
  | 	com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:113)
  | 	javax.faces.webapp.FacesServlet.service(FacesServlet.java:244)
  | 	org.jboss.seam.servlet.SeamRedirectFilter.doFilter(SeamRedirectFilter.java:32)
  | 	org.jboss.seam.servlet.SeamExceptionFilter.doFilter(SeamExceptionFilter.java:46)
  | 	org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
  | 
  | 


Take out the...


  | <h:panelGrid binding="#{numberGuess.dynamicPanelGrid}" />

from the .xhtml and everything works great. The numbers update as before and begin() only gets called once, as expected.

So.... what am I doing which causes a panelGrid bound to a bean property to blow up when using ScopeType.CONVERSATION ?

Thanks


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