SetActionListener checking date on DB

Question

Hi All,
I want to set an action listener on my submit button, which it can check/validate data from DB first. for example: i want to insert "dataRow01" on "17 june 2008" then if i want to insert "dataRow02" on the same date (17 june 2008), i want to make it blocked or displaying alert page or something. So what value should i put on the setActionListener?
<af:commandButton text="Submit">
<af:setActionListener from="#{bindings.UserabsentableView1Date.inputValue}"
to="<What should I put here to check the DB??>"/>
</af:commandButton>
Thank you very much.
Regards,
Hadi Wijaya

Answer 1

i've tried to change the model. it works for one variable.
but i have 2 variable : username and date to check into DB,
one username cannot inserting data twice or more a day....mostly like that.
and i tried to use method validator (entity editor > validation > validation rule --> method validator)...which i can put a code from editor...but i have still a problem with this :
public boolean validateDateUsername(Date data, String usrname) {
                              +--------- what should i fill into ----------+
                               |                                                    |
                               V                                                  V
if( data != <check into DB> && username==<sessionScope.username> ) {
return true;
return false;
or do you have any suggestion?? or sample maybe?
i very confuse of this...
Thanks