Struts - initialize ActionForm

Question

Hey,
What I need to do:
I need to implement a search form, which gives the user the ability to put in some search criteria. These search criteria include 3 comboboxes (html:select). These comboboxes should be populated with database values.
I've created an ActionForm object to store the user's search criteria. I suppose that I need the same object to populate my comboboxes. I found that I could populate these dynamically, using the following construction:
<html:form action="search.do>
<html:select property="artGroup">
<html:options property="artGroups" labelProperty="artGroups"/>
</html:select><br>
<html:submit/>
<html:reset/>
</html:form>
The property artGroups is mapped to an ArrayList object of the ActionForm object.
To query the correct values (from the database) for populating the comboboxes I need a parameter that is passed by as a request parameter.
Now, my question is: how can I pass this request parameter to my ActionForm object, before any getters are executed to build the HTML form object.
Thank you very much for your help

Answer 1

The simplest solutions might be to access that parameter from inside your ActionForm constructor
e.g.
public class MyForm extends ActionForm{
     MyForm(){
         super();
         // here goes a call to get that parameter
}Or you can subclass RequestProcessor, and override processActionForm(request, response, mapping). Do something like
protected ActionForm processActionForm (HttpServletRequest req,
                                        HttpServletResponse res,
                                        ActionMapping mapping){
       ActionForm form = super.processActionForm(req, res, mapping);
       // ensure that "form" is actually instance of MyForm
       // if it is not, simply return form
       // if it is, get the parameter you need for your form and again
       // return it.
}