Question

I have an Action, called ShowData that recovers data from the database and put it in the jsp.

struts.xml

...
<action name="ShowData" class="foo">
   <result>foo.jsp</result>
</action>
...

In the foo.jsp page I have a form and the data that I have obtained with the ShowData action.

foo.jsp

...
<s:form action="DoSomething">
   <s:input key="email" />
   <s:submit/>
</s:form>
<s:iterator value="data_recovered_in_ShowData">
   ...
</s:iterator>
...

Now I want to add some validation to data. If the return type of DoSomething is something like this: <result name="input">foo.jsp</result> I will lose the data that I recover in ShowData action, but the validation works perfectly and the previous input of the user and the error will be showed in the jsp page.

On the other hand, I know that I can use chain, to do something like <result name="input" type="chain">ShowData</result> and then use MessageStoreInterceptor to recover the data (but I still don’t know how to recover the previous data that the user had introduced in the input). But this is a solution that I’m trying to avoid since I read that using chain is not a good idea.

So then, how do I add some validation in this case without losing any data and without using chain?

Answer 1

If your concern is just retrieving DB data in the first action you have a few options.

1. Use Preparable and have both actions retrieve the data using the appropriate service.
2. Same, but have both actions inherit the prepare method from a superclass.
3. Keep the data in session until not needed (can be done manually, using an interceptor, etc.)

If your concern is previous form data (not indicated in the question) then you have similar options:

1. Hidden fields (as Tapan’s answer), but you’d still need to validate it if it’s not already in the DB. (If it’s in the DB you can retrieve it. If it’s not and you have a validation error on the hidden data you’d need to redirect back to the previous form.)
2. Keep that data in session, avoiding revalidation. Remove the data on successful submit. (Again doable via existing or new interceptor, or manually.)

There are likely a few other options for either scenario as well.

Ultimately, if you’re using chain only for data retrieval, that’s a bad idea–that’s precisely the scenario that Preparable is for, and eliminates the coupling between actions.