Java Development Tools

I have an attribute CategoryId in my VO of type oracle.jbo.domain.Number. I am trying to use the expression of Boolean item in JSF as #{row.CategoryId != 4}
Here is the JSF code:

                      <af:column id="s141NewItem3Col" noWrap="true" width="100"
                                 rowHeader="false">
                        <f:facet name="header">
                          <af:outputLabel value="CAtIDDeq4" showRequired="false"
                                          id="ol18"/>
                        </f:facet>
                        <af:inputText id="s141NewItem3"
                                      value="#{row.CategoryId != 4}"
                                      label="CAtIDDeq4" required="false"
                                      readOnly="#{((pageFlowScope.ContractRightCategoriesTable.newRow) and (!(jhsUserRoles['RM, ADMIN, AllButTitl, AllButAdmn']))) or ((!pageFlowScope.ContractRightCategoriesTable.newRow) and (!(jhsUserRoles['RM, ADMIN, AllButTitl, AllButAdmn'])))}"></af:inputText>
                      </af:column>

I am getting the run time exception as "Can not convert 4 of type class oracle.jbo.domain.Number to class java.lang.Long".

I am wondering how the row.CategoryId is treated as Long?. PLease advise. Also, will I be able to use type casting expressions in JSF Expression Language?

Thanks, Pradeep