struts jqgrid server validation error messages - validation

Question

I have a project using Struts2 on the server side and I am trying to make it work with jqGrid (using JSON format). I have several tables made with jqGrid and I am using the add/edit/delete buttons from navGrid.
The main problem I have is with server validation error messages. I have created custom validators and they work with jsp pages, using s:fielderror, but I don't know how to make them work for add/edit popups from jqGrid. I am aware that jqGrid provides the users with custom validation on client, but this has its limitations(think about testing whether the email of a user is unique, you definitely must use the database for that, or if some fields depend on each other and must be tested together, like if isManager is true, then the managerCode must be not empty and vice versa...).
When I use the client validation, there is a message in the add/edit window whenever an error occurs. Can I somehow display my server validation error messages in the window in the same way?

Answer 1

I managed to solve the issue. I will explain how using a simple custom validator for age field, which must be > 18 for an Employee. It is supposed next that the validator was already declared in validators.xml and mapped on the action and that the message in case of ValidationException is "An employee should be older than 18.".
Using Firebug, I figured out that the id of the error area in the form is FormError. It is possible to configure a callback function errorTextFormat in jqgrid, in order to get a response from the server and process it. In the jqgrid configuration, one could write
errorTextFormat : errorFormat,
with
var errorFormat = function(response) {
var text = response.responseText;
$('#FormError').text(text); //sets the text in the error area to the validation //message from the server
return text;
};
The problem is now that the server will send implicitly a response containing the whole exception stack trace. To deal with it, I decided to create a new result type.
public class MyResult implements Result {
/**
*
*/
private static final long serialVersionUID = -6814596446076941639L;
private int errorCode = 500;
public void execute(ActionInvocation invocation) throws Exception {
ActionContext actionContext = invocation.getInvocationContext();
HttpServletResponse response = (HttpServletResponse) actionContext
.get("com.opensymphony.xwork2.dispatcher.HttpServletResponse");
Exception exception = (Exception) actionContext
.getValueStack().findValue("exception");
response.setStatus(getErrorCode());
try {
PrintWriter out = response.getWriter();
out.print(exception.getMessage());
} catch (IOException e) {
throw e;
}
}
/**
* #return the errorCode
*/
public int getErrorCode() {
return errorCode;
}
/**
* #param errorCode the errorCode to set
*/
public void setErrorCode(int errorCode) {
this.errorCode = errorCode;
}
}
It must also be configured in struts.xml as follows:
<package name="default" abstract="true" extends="struts-default">
...
<result-types>
<result-type name="validationError"
class="exercises.ex5.result.MyResult">
</result-type>
</result-types>
...
<action name="myaction">
...
<result name="validationException" type="validationError"></result>
<exception-mapping result="validationException"
exception="java.lang.Exception"></exception-mapping>
</action>
...
</package>
These are the steps I followed to get a validation error message in the add/edit window and now it works.