Question

I have a JSF page that contains two subviews. Depending on which commandButton is executed, one of the subviews is rendered. However, if validation fails on one of the subviews, the error messages stay visible and the components are still invalid the next time the subview is rendered. I have a workaround in my bean to remove the messages but the components stay invalid. Is there a way to set the components as valid or create a new view for the subview only?

Here is my work around for the messages:

Iterator messageIterator = FacesContext.getCurrentInstance().getMessages();
    while (messageIterator.hasNext()) 
    {
            messageIterator.remove();
    }

Answer 1

This is caused by the fact that when rendered is false the component is not shown, but it still is in the component tree for the view. So the component does not show but its values and state are still there.

There are several ways around this:

• Use JSTL tags such as <c:if /> (if at all possible) instead of rendered. Page elements inside a <c:if/> tag will be in the tree only if the condition is true.

• Don’t do a postback when passing from one subview to the other. This effectively recreates the tree from scratch. For example perform a GET instead of a POST.

• Invalidate the view so that the tree is recreated. Make the commandButton that switches subviews immediate="true" and invalidate the view adding this code:

public void clearComponentTree() {
    FacesContext context = FacesContext.getCurrentInstance();
    Application application = context.getApplication();
    ViewHandler viewHandler = application.getViewHandler();
    UIViewRoot viewRoot = viewHandler.createView(context, context.getViewRoot().getViewId());
    context.setViewRoot(viewRoot);
    context.renderResponse();
}

• Directly manipulate the component tree deleting unwanted components (similar to the above, but limited to specific components). Here I assume we want to delete all components under a subview with id sub1 (this requires immediate="true" as well):

public void clearSubtree() {
    FacesContext context = FacesContext.getCurrentInstance();
    context.getViewRoot().findComponent(":sub1").getChildren().clear();
}

this link provides other minor ways of achieving this.