Component MethodBinding NullPointerException

Question

Hey everybody.. this is an issue that has been giving me problems for a while now, and I haven't been able to figure it out. I've created a menu bar component which I use in this fashion in my pages:
<or:menuBar pageClass="#{menuBarBean.PAGECLASS_HOME}" msg="#{menuBarBean.numQuestionsMessage}" />In my renderer for this component, I have set up HtmlCommandLinks which are supposed to invoke navigation methods in my MenuBarBean. The problem is, whenever I click on one of the links, a NullPointerException is thrown in my renderer's encodeEnd method.
All the piping seems to be working for the tag and the component.. meaning the "pageClass" and "msg" attributes get set and rendered properly on the menuBar. Also the thing renders correctly, but I have a feeling that I'm not setting the MethodBinding correctly for the "Action" property of the CommandLink, or I'm not setting it in the right place. Here's an abbreviated version of the code behind the component:
In my 'MenuBar.java' class:
public void setHomeBinding(MethodBinding mb)
{ homeBinding = mb; }
public MethodBinding getHomeBinding()
{ return homeBinding; }In the 'setProperties' method of my 'MenuBarTag.java' class:
MethodBinding mb = getFacesContext().getApplication().createMethodBinding("#{menuBarBean.gotoHome}", null);
menuBar.setHomeBinding(mb);In the 'encodeEnd' method of 'MenuBarRenderer.java' (Here's where I create the link and set the Action to the MethodBinding)
// If is this class, show a selected tab
if(menuBar.getPageClass().equals(MenuBarBean.PAGECLASS_HOME))
     HtmlGraphicImage homeButton = (HtmlGraphicImage)application.createComponent(HtmlGraphicImage.COMPONENT_TYPE);
     homeButton.setUrl(IMG_HOME_SRC_SELECTED);
     menuBar.getChildren().add(homeButton);
// else Render the button
else
     HtmlSwapImage homeSwapImg = (HtmlSwapImage)application.createComponent(HtmlSwapImage.COMPONENT_TYPE);
     homeSwapImg.setUrl(IMG_HOME_SRC_IDLE);
     homeSwapImg.setSwapImageUrl(IMG_HOME_SRC_OVER);
     homeSwapImg.setStyleClass("menuBarButton");
     HtmlCommandLink homeButton = (HtmlCommandLink)application.createComponent(HtmlCommandLink.COMPONENT_TYPE);
     homeButton.setAction(menuBar.getHomeBinding());
     homeButton.getChildren().add(homeSwapImg);
     menuBar.getChildren().add(homeButton);
menuBar.getChildren().add(spacer);
RendererUtils.renderChildren(facesContext, menuBar);
menuBar.getChildren().removeAll(menuBar.getChildren());And finally, in my MenuBar backing bean 'MenuBarBean.java'
public String gotoHome()
{ return("goto-home"); }
public String getPAGECLASS_HOME()
{ return PAGECLASS_HOME; }Now, like I said.. The appearance of the whole thing renders properly, image swapping and all. Just that whenever you click on one of the buttons, I get an execption, and a stack trace that looks sorta like:
ERROR[jsp]:704 - Servlet.service() for servlet jsp threw exception
java.lang.NullPointerException
    at packageName.MenuBarRenderer.encodeEnd(MenuBarRenderer.java:173)
    at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:331)
    at javax.webapp.UIComponentTag.encodeEnd(UIComponentTag.java:349)
    at javax.faces.webapp.UIComponnetTag.doEndTag(UIComponentTag.java:253)
.Anybody have any suggestions, or see any glaring problems in my coding? Any help would be much appreciated. Thanks!

Answer 1

Sure.. this snippet starts at 173:
if(!(menuBar.getMsg().equals(null)))
     writer.startElement(HTML.SPAN_ELEM, menuBar);
          writer.writeAttribute(HTML.CLASS_ATTR, "msgText", null);
          writer.write(menuBar.getMsg());
     writer.endElement(HTML.SPAN_ELEM);
}The thing is, this section of code works normally. It only throws an exception when I click on a link.