Can I update a JSF component from a JSF backing bean method?

Question

Is there a way to have a JSF Backing bean cause an update of a component on the page? I am not looking to use an ajax component with update attribute to update a component on the page. I need to trigger an update from within a JSF backing bean method. Note the update on the page can happen after this method completes or prior to its completion. I am using PrimeFaces, if there is a solution that can be had from using PrimeFaces.

Answer 1

Using standard JSF API, add the client ID to PartialViewContext#getRenderIds().

FacesContext.getCurrentInstance().getPartialViewContext().getRenderIds().add("foo:bar");

Using PrimeFaces specific API, use PrimeFaces.Ajax#update().

PrimeFaces.current().ajax().update("foo:bar");

Or if you're not on PrimeFaces 6.2+ yet, use RequestContext#update().

RequestContext.getCurrentInstance().update("foo:bar");

If you happen to use JSF utility library OmniFaces, use Ajax#update().

Ajax.update("foo:bar");

Regardless of the way, note that those client IDs should represent absolute client IDs which are not prefixed with the NamingContainer separator character like as you would do from the view side on.

Answer 2

I also tried to update a component from a jsf backing bean/class

You need to do the following after manipulating the UI component:

FacesContext.getCurrentInstance().getPartialViewContext().getRenderIds().add(componentToBeRerendered.getClientId())

It is important to use the clientId instead of the (server-side) componentId!!

Answer 3

The RequestContext is deprecated from Primefaces 6.2. From this version use the following:

if (componentID != null && PrimeFaces.current().isAjaxRequest()) {
    PrimeFaces.current().ajax().update(componentID);
}

And to execute javascript from the backbean use this way:

PrimeFaces.current().executeScript(jsCommand);

Reference:

• https://github.com/primefaces/primefaces/wiki/Migration-Guide
• https://forum.primefaces.org/viewtopic.php?t=53129

Answer 4

Everything is possible only if there is enough time to research :)

What I got to do is like having people that I iterate into a ui:repeat and display names and other fields in inputs. But one of fields was singleSelect - A and depending on it value update another input - B. even ui:repeat do not have id I put and it appeared in the DOM tree

<ui:repeat id="peopleRepeat"
value="#{myBean.people}"
var="person" varStatus="status">

Than the ids in the html were something like:

myForm:peopleRepeat:0:personType
myForm:peopleRepeat:1:personType

Than in the view I got one method like:

<p:ajax event="change"
listener="#{myBean.onPersonTypeChange(person, status.index)}"/>

And its implementation was in the bean like:

String componentId = "myForm:peopleRepeat" + idx + "personType";
PrimeFaces.current().ajax().update(componentId);

So this way I updated the element from the bean with no issues. PF version 6.2

Good luck and happy coding :)

Answer 5

In order to updte the component from backing bean, we can achieve as below RequestContext.getCurrentInstance().update('updatePanelGroup');

<h:panelGroup id="updatePanelGroup">
    .....
    ....
</h:panelGroup>

Updating the component differs with respect to prima face version.