ProlongCopy.java

public class ProlongCopy
       extends IlybraAction
{
    public ActionForward execute(ActionMapping mapping,
                                 ActionForm form,
                                 HttpServletRequest request,
                                 HttpServletResponse response)
    {
        BookForm bookForm = (BookForm) form;
        String prolongDate = bookForm.getReturnDate();
        Library library = getWorld().getLibrary(); //the first reason for
                                                   //the base IlybraAction class

        Copy copy = library.getCopies().getCopyById(
                    bookForm.getCopyId()
        );
        Utils.notNullAssertion("Copy: ", copy);
                                //I wait for this to become an aspect :)

        library.prolongCopy(copy, Dates.someDateByString(prolongDate));
        saveOneMessage(request, "message.prolong.change.success",
                                copy.getSignature());
                                //second reason for IlybraAction

        return mapping.findForward("success");
    }
}