Problems in VALUECHANGELISTNER in JSF

Question

I am developing a web application using IBMs RAD tool. with websphere 5.0 test environment.
I am using JSF. Here I have a a selectone dropdown menu ,input text boxes followed by another selectone dropdown menu and then few checkboxes. I have a valuechangelistner for both the dropdown menus, on the value change event of the 1st dropdown I need to display some data onto the screen. I am doing this by callin the value change event in my PAGECODE (manage bean) and this is working fine. And when there is a change in value in the second dropdown then I need to disable/enable the checkboxes based on the value in the 2nd dropdown
This is not happening.
I am using "disabled" attribute for the checkboxes which are bound to boolean variables declared in my databean. These vales are changed at runntime.
This is wat I am doing before calling the value change listner method in the pagecode, I am submiting the form in which the "selectone menu"
is present and than the valuechange listner method is called. When I debug the code at runtime the boolean variables are having correct values but once the form is reloaded after completing the pagecode the previous values are overwritten. Thus the checkboxes are not geting enabled and disabled properly.
Is there anything I am missing while calling the "valuechange listner" on the pagecode ? And manyof my colleagues are facing whenever we use the "disabled" attribut on "booleancheckboxes" and "radio buttons".
Can somebody explain more on this "erase()" method.
We are having a work around by using hidden text fields and then disabling/enabling check boxes using JAVA Script.
Also I tried using two forms: I kept the first dropdown in the first form and the second dropdown in the second form. Is there a way to stop one of the forms from loading at one time manually ?
Do u think by upgrading the test environment to 5.1 this problem will be solved ?

Answer 1

Usually, a value change listener is invoked just after the Process Validations phase.
Then, the lifecycle proceeds to the Update Model Values phase.
If you also bind the boolean variables in your databean to some input components,
the variables are set as the local values of those components which may be
the old ones.
If this is the situation, you have three different ways to solve it.
(1) invoke facesContext.renderResponse() in the value change listener
which will skip the Update Model Values phase.
(2) change the phase of processing the value change event.
(3) not use the value change listener.
In your case, this is the simplest way I think.
For example, you can write some simple code as follows:
public boolean getDisabled() {
if (some condition for the value of 2nd dropdown) {
    return true;
} else {
    return false;
}