Custom Validator for checking duplicate values with database

[tanalyw]

Hi,

I am rather new to the struts validation framework. I am using struts 1.3.5.
I need to provide client side validation using the framework. I would like a popup to appear if the input entered by user is a duplicate of what is in the database.

public class customValidator {

//method to check duplicate
public boolean checkDuplicate(....) {
//get values from database, match and return false if matched

}

How to I enable a popup to appear?

[tanalyw]

validation.xml I have the following lines.
<formset>

<form name="testForm">
<field property="typeName"
depends="required,checkDuplicate">
<arg0 key="testForm.typeName"/>
</field>
</form>
</formset>

validator-rules.xml I have the following.

<validator name="checkDuplicate"
classname="test.customValidator"
method="checkDuplicate"
methodParams="java.lang.Object,
org.apache.commons.validator.ValidatorAction,
org.apache.commons.validator.Field,
org.apache.struts.action.ActionMessages,
org.apache.commons.validator.Validator,
javax.servlet.http.HttpServletRequest"
msg="errors.checkDuplicate"/>

Do i need to input the javascript? If yes, how?