Untitled

public class UserAction extends ActionSupport{

    public void validate(){
        if(!firstName.equals("JimB77")){
            //addFieldError(firstName, "first name is not equal to JimB77");
            addActionError("You have an error on your inputs..");
        }
    }

    public String performAnalysis(){
        System.out.println("perform analysis logic..");
        return SUCCESS;
    }


    private String firstName;
    private String lastName;

    //getters and setters

}

public void validatePerformAnalysis(){
        if(!firstName.equals("JimB77")){
            //addFieldError(firstName, "first name is not equal to JimB77");
            addActionError("You have an error on your inputs..");
        }
    }

<result name="input">/pages/user.jsp</result>

<action name="performAnalysis" class="x.y.z.action.UserAction" method="performAnalysis">
            <result name="success">pages/user.jsp</result>
            <result name="input">/pages/user.jsp</result>
        </action>

<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>

<script>
var error="";
function showDialog(msg){
        alert(msg);
}
</script>
</head>

<body>

<s:form action="/performAnalysis" >

    <s:textfield name="firstName" />
    <s:textfield name="lastName" />
    <s:submit value="Submit" />

</s:form>
   <s:if test="hasActionErrors()">
     //<s:actionerror />
      <s:iterator var="error" value="actionErrors">
        <script>
              error += "<s:property value='#error' />";
            </script>
      </s:iterator>
      <script>
        showDialog(error);
      </script>
   </s:if>
</body>
</html>