Problem with forward in the struts-config.xml-File

[Michael Ernst]

Hey,
I have a little problem withd by understanding the forward element in the struts-config.xml-File.
The problem: I have an overview side with diffrent record sets. Each record has an edit link. If the record will be successfully updated, I want to forward to the overview side but everytime I get an exception that no collection was found ([ServletException in:/jsp/admin/logged/showAdmin.jsp] No collection found'). Only If I make a forward direct to the *.do page the page will be loaded correctly.

<!-- Edit Admin ==================================================== -->
        <action path="/admin/logged/showAdmin"
                type="de.dainel.webapp.shop.admin.ShowAdminAction"
                name="ListForm"
                scope="request"
                input="shop.showAdmin">
            <forward name="success" path="shop.showAdmin"/>
        </action>
 
<action path="/admin/logged/prepareEditAdmin" 
type="de.dainel.webapp.shop.admin.PrepareEditAdminAction"
name="editAdminForm" 
scope="request" 
input="shop.editAdmin">
<forward name="success" path="shop.editAdmin"/>
</action>

<action path="/admin/logged/processEditAdmin" 
type="de.dainel.webapp.shop.admin.ProcessEditAdminAction" 
name="editAdminForm" 
scope="request" 
input="shop.editAdmin"
validate="true">
<forward name="success" path="/admin/logged/showAdmin.do"/>
<!-- <forward name="success" path="shop.showAdmin"/> generates the error -->
</action>

[Kerry Wilson]

How are you accessing the records in the jsp file?

It doesn't seem like your action mappings are the problem. Please post jsp and action code (if applicable).

[Michael Ernst]

The interesting JSP-Code:

  <html:form action="/admin/logged/showAdmin">
        <nested:root name="ListForm">
                <nested:iterate id="currentAdmin"
                                property="list"
                                type="de.dainel.webapp.shop.dataresources.ShopSystemAdmin">
                    <tr>
                        <td><nested:write property="username" /></td>
                        ...
                        <td><html:link action="/admin/logged/prepareEditAdmin" 
paramId="admin" paramName="currentAdmin" paramProperty="adminId">Edit</html:link></td>
                    </tr>
                </nested:iterate>
        </nested:root>
        </html:form>

The Form Bean

<form-bean name="ListForm" type="de.dainel.webapp.shop.ListForm"></form-bean>
 
import java.util.List;
import org.apache.struts.action.ActionForm;
public class ListForm extends ActionForm {
    private List list;
 
    public List getList() {
        return list;
    }
 
    public void setList(List list) {
        this.list = list;
    }
}

The action class:

public class ShowAdminAction extends Action{
    public ActionForward execute(ActionMapping actionMapping,
            ActionForm actionForm,
            HttpServletRequest httpServletRequest,
            HttpServletResponse httpServletResponse)
throws Exception {
// The data is accessible by using the O/R-Mapper Torque.
((ListForm)actionForm).setList(ShopSystemAdminPeer.doSelect(new Criteria()));
return actionMapping.findForward("success");
}
}

[ August 15, 2005: Message edited by: Michael Ernst ]
[ August 15, 2005: Message edited by: Michael Ernst ]

[Kerry Wilson]

Everything looks good to me, I would put some logging code to make sure the method, ShopSystemAdminPeer.doSelect(new Criteria()) is returning what you want it to return. Though, I do not have any experience with the nested tag library.

I don't know if the error generated is a result of a null value returned or maybe it cannot see the form at all. Is the property username output? If it is maybe you should initialize list to an empty collection in your form.

[Michael Ernst]

I put some simple Code in front of the setting of ActionForm.

    System.out.println("Hello World!");
((ListForm)actionForm).setList(ShopSystemAdminPeer.doSelect(new Criteria()));
System.out.println(actionForm);
return actionMapping.findForward("success");

But I get no output. The exectute method is never executed but why?

Regards
Michael
[ August 15, 2005: Message edited by: Michael Ernst ]

[Kerry Wilson]

Are you accessing through the action servlet? (i.e with request to uri /admin/logged/showAdmin.do )

Have you overriden the validate method int the form to return errors?

These are the only reasons that I can think of.

[Michael Ernst]

Are you accessing through the action servlet? (i.e with request to uri /admin/logged/showAdmin.do )

If I'm accessing through the showAdmin.do direcly or forward to the showAdmn.do, the page will be loaded correctly. Only If I'm accessing throung the jsp Page by forwarding, the code generates the error.

<action path="/admin/logged/processEditAdmin" 
type="de.dainel.webapp.shop.admin.ProcessEditAdminAction" 
name="editAdminForm" 
scope="request" 
input="shop.editAdmin"
validate="true">
<forward name="success" path="shop.showAdmin"/>
</action>
 
Tiles:
<definition name="shop.showAdmin" extends="shop.default">
<put name="mainwindow" value="/jsp/admin/logged/showAdmin.jsp"/>
</definition>

Have you overriden the validate method int the form to return errors?

Yes, the validate method is overridden.

Class ListForm:
...
public ActionErrors validate(ActionMapping mapping, HttpServletRequest request){
  return new ActionErrors();
}
...

Regards
Michael

[Kerry Wilson]

If you are forwarding to the tile from another Action the execute method will not be executed and your list will be null.

Otherwise, you cannot be taking about the forward from the current action, because that would require the execute method and thus the list will be populated.

Therefore, you must forward to the action from the processEditAdmin? action.
[ August 15, 2005: Message edited by: Kerry Wilson ]

[Kerry Wilson]

Upon further review, these actions seem to be pretty similar. Maybe you should create a DispatchAction.