validate struts2 form other than validation framework

In my Struts2 JSP form, there are text fields and a select tag. For example,

<s:form>
<s:textfield name="name" label="Name"/>
<s:textfield name="dob" label="Date of Birth"/>
<s:select name="degree" list="degreeList" listKey="degreeID" listValue="degreeName"/>
<s:submit/>
</s:form>

Before this JSP is loaded, I filled degreeList in action class. I need to validate this form. So I tried the validation framework. But the problem is action class return "input" itself if the validation failed. I cannot refill the degreeList if the validation failed. So the above JSP cannot be loaded. The error says degreeList is not list/collection as the list is no longer in the value stack. Somebody please kindly guide me how can I validate in another way? Thanks.

Solution

All your problem have to be solved is repopulate the lists when you return from the validate() method. I guess your action extends the ActionSupport, if not then you should do it. Override the validate() method. There you should check hasActionErrors() and hasFieldErrors(). If any then repopulate lists. As a good practice you should separate the code that used to render JSP and reuse it in the validate method. After validate() the INPUT result returned without action execution.