How do I add ajax behavior to a dynamically created component in a backing bean?

Question

In respose to Infragile's request in another thread, I am asking this as a separate question rather than a followup.

Here is the problem I am attempting to address: I'm migrating from JSF1.2 to JSF2. Everything worked fine in JSF1.2. I have rewritten a critical item to be a composite component which is basically a panel created in my backing bean by adding components in code.

In particular, I have h:inputText and h:selectOneMenu components that I create in code along with an "Apply" h:commandButton. The "Apply" button has an action listener that checks for the values in the h:inputText and h:selectOneMenu components. All this works fine, but when I fetch the values in the h:inputText or h:selectOneMenu components I get the original values, not the new values that were entered by the user. Like I said, this worked fine in JSF1.2 (i got the new values), but not in JSF2 for some reason.

I have tried several things to get around this that haven't worked, so I figured I would add ajax behavior to the h:inputText and h:selectOneMenu items and when the values in these components change, I could call another backing bean listener for the ajax behavior to fetch the new values.

I am trying to add ajax behavior to a component I create in code (not bound to a page component). I can create the component with no problem. However, the problem that I am having is how to add the ajax behavior to the component.

Could someone post sample code to add an ajax behavior for a value change or blur event? Here is the code I use to create the component in code - how would I need to modify it to add the ajax behavior? hpg = new HtmlPanelGrid(); children = hpg.getChildren(); children.clear(); .... input = new HtmlInputText(); .... children.add(input);

What code would I have to add to replace the "add ajax behavior here" line, and what would the arguement for the listener method be (arguement for the method to replace the ????? below)?

public void myAjaxListener(?????) { ...... {

I have been trying to get a handle on this for some time now. I feel that I am pretty close, but don't know the syntax I need. I can provide more information on how I am fetching the component Ids and searching for the values in my action listener if that will help.

Thanks

Ondrej Bozek Ondrej Bozek · Accepted Answer · 2011-10-07T14:13:36

This is how you can add dynamically AjaxBehaviorListener to yor component:

...
HtmlInputText inpuText = new HtmlInputText();
AjaxBehavior blurBehavior = new AjaxBehavior();
blurBehavior.addAjaxBehaviorListener(new BlurListener());
blurBehavior.setTransient(true);
inputText.addClientBehavior("blur", blurBehavior)
...

public class BlurListener implements AjaxBehaviorListener {

    public BlurListener() {
    }

    @Override
    public void processAjaxBehavior(AjaxBehaviorEvent event) {
        // do your job
        HtmlInputText inputText = event.getComponent(); // your input text component
        ...
    }
}

"blur" represents event when this listener will be triggered. Remember that JSF Component must support this event, otherwise it won't work.
(Here you can see under covers and how to build custom AJAX component http://weblogs.java.net/blog/driscoll/archive/2009/10/09/jsf-2-custom-java-components-and-ajax-behaviors?force=670 )

However in your case I think problem is that buttons ActionListener is triggered before actual component values are submited. You can solve it by moving your ActionListener logic to button action, by aformentioned AJAX, maybe by findinng actual values in UIComponents (HtmlInputText, UISelectOne), not sure but immediate attribute can also influence it.

How do I add ajax behavior to a dynamically created component in a backing bean?

1 Answers