Using a4j:support's onchange event with h:selectOneMenu

Question

<h:selectOneMenu id="selectOneMenu"  value="#{Bean1.val1}" >
    <f:selectItems value="#{Bean1.selectItems}"/>
    <a4j:support event="onchange" action="#{Bean1.onSelectOneMenuChange}" reRender="textbox1 , textbox2 , textbox3, textbox4"  />
 </h:selectOneMenu>

<h:inputText id="textbox1" value="#{Bean1.textbox1}"> </h:inputText>
<h:inputText id="textbox2" value="#{Bean1.textbox2}"> </h:inputText>
<h:inputText id="textbox3" value="#{Bean1.textbox3}"> </h:inputText>
<h:inputText id="textbox4" value="#{Bean1.textbox4}"> </h:inputText>

Bean1.onSelectOneMenuChange() will change the value of Bean1.textbox1, Bean1.textbox2,Bean1.textbox3 and Bean1.textbox4(depending on the value selected (Bean1.val1)). Sometimes, it will change all the textbox value and sometimes it will only changes some textbox value.

When users change the value in the "selectOneMenu" drop down list control , the JSF framework will not call the update model values phase but call the Bean1.onSelectOneMenuChange() directly. After that, the all the textbox are reRender. Because the update model values phase is not called, the values entered by the user is never set the the Bean1 and the original value is shown in the textbox after reRender.

I want to ask:

1. How can I manually call the update model values phase inside Bean1.onSelectOneMenuChange()? How can I get the value input input by the users inside Bean1.onSelectOneMenuChange() and set it to the corresponding fields of the Bean1?

2. Another approach is that only reRender those textbox whose values are updated inside the Bean1.onSelectOneMenuChange() .However , there are many case . For example, a value will change all the textbox value and a values may only change some textbox value.How can I reRender conditionally? What method is more prefer for maintainability?

Update :

For point 2 , I find that the reRender preperties of the can accept the EL expression , so I tried to use

 <a4j:support event="onchange"  action="#{Bean1.onSelectOneMenuChange}" reRender="#{Bean1.reRenderIDList}"  /> .

Inside the Bean1.onSelectOneMenuChange(), I set the Bean1.reRenderIDList to a set of ID that required to be reRender based on the business requirement. The Bean1.getRenderIDList() runs when the page is refresh. However, when I change the value of <h:selectOneMenu> in the UI , Bean1.getRenderIDList() will never run again. Thus, the textbox cannot be reRender?

Any idea?

Answer 1

Your code looks fine. There is no reason for Update Model phase not to happen (you don't use immediate=true). And if you had conversation/validation error, then the action would never be called. Check what phases you go through.