Struts2 - Dynamic values in expression while doing validations using annota

Question

Hi,
I am using Struts2. I am doing validations using annotations in action class.
I have many forms having same type of fields say zip code.
I am adding validations like below in each action class having zip code field
@Action(value = "/saveData")
@Validations(
     regexFields = {
          @RegexFieldValidator(fieldName = "databean.zipCode", expression = "^([1-9]{1}[0-9]{4}(-[0-9]{4})?)$", key = "errors.zipcode.format", message = "errors.zipcode.format")
public String saveData() throws Exception {
Now, in case if I need to change the expression for zip code validations, then I need to modify the same in each action class.
I would like to know if there is any way to use java variable or property for expression so that i only need to change at one place (value of variable) and all actions get modified.
I want something like below
private static final String ZIP_CODE_FORMAT_EXPRESSION = "^([1-9]{1}[0-9]{4}(-[0-9]{4})?)$"
@Action(value = "/saveData")
@Validations(
     regexFields = {
          @RegexFieldValidator(fieldName = "databean.zipCode", expression = "${ZIP_CODE_FORMAT_EXPRESSION}", key = "errors.zipcode.format", message = "errors.zipcode.format")
public String saveData() throws Exception {
Thanks
Krishan Babbar

Answer 1

Thanks
That is working..
I defined my expression as constant in my another file and it is working fine....
One more question i need to check space in expression but its not working... I tried following:
expression = "^([a-zA-Z0-9@_.-\\s]+)$" and expression = "^([a-zA-Z0-9@_.-\\\\s]+)$"