An ActionForm is a JavaBean optionally associated with
* one or more ActionMappings. Such a bean will have had its
* properties initialized from the corresponding request parameters before
* the corresonding action's execute method is called.
When the properties of this bean have been populated, but before the
* execute method of the action is called, this bean's
* validate method will be called, which gives the bean a chance
* to verify that the properties submitted by the user are correct and valid.
* If this method finds problems, it returns an error messages object that
* encapsulates those problems, and the controller servlet will return control
* to the corresponding input form. Otherwise, the validate
* method returns null, indicating that everything is acceptable
* and the corresponding Action's execute method should be
* called.
This class must be subclassed in order to be instantiated. Subclasses * should provide property getter and setter methods for all of the bean * properties they wish to expose, plus override any of the public or * protected methods for which they wish to provide modified functionality. *
* *Because ActionForms are JavaBeans, subclasses should also implement
* Serializable, as required by the JavaBean specification.
* Some containers require that an object meet all JavaBean requirements
* in order to use the introspection API upon which ActionForms rely.
null.
*/
protected transient MultipartRequestHandler multipartRequestHandler;
// ------------------------------------------------------------- Properties
/**
* Return the controller servlet instance to which we are attached.
*/
protected ActionServlet getServlet() {
return (this.servlet);
}
/**
* Return the controller servlet instance to which we are attached.
* as an ActionServletWrapper.
* @see org.apache.struts.action.ActionServletWrapper
* @since Struts 1.0.1
*/
public ActionServletWrapper getServletWrapper() {
return new ActionServletWrapper(getServlet());
}
/**
* Return the MultipartRequestHandler for this form
* The reasoning behind this is to give form bean developers
* control over the lifecycle of their multipart requests
* through the use of the finish() and/or rollback() methods
* of MultipartRequestHandler. This method will return
* null if this form's enctype is not
* "multipart/request-data".
* @see org.apache.struts.upload.MultipartRequestHandler
*/
public MultipartRequestHandler getMultipartRequestHandler() {
return multipartRequestHandler;
}
/**
* Set the controller servlet instance to which we are attached (if
* servlet is non-null), or release any allocated resources
* (if servlet is null).
*
* @param servlet The new controller servlet, if any
*/
public void setServlet(ActionServlet servlet) {
this.servlet = servlet;
}
/**
* Set the Handler provides to use in dealing with file uploads.
* @param multipartRequestHandler The Handler to use for fileuploads.
*/
public void setMultipartRequestHandler(MultipartRequestHandler multipartRequestHandler) {
this.multipartRequestHandler = multipartRequestHandler;
}
// --------------------------------------------------------- Public Methods
/**
* Reset all bean properties to their default state. This method is
* called before the properties are repopulated by the controller servlet.
* * The default implementation attempts to forward to the HTTP * version of this method. * * @param mapping The mapping used to select this instance * @param request The servlet request we are processing */ public void reset(ActionMapping mapping, ServletRequest request) { try { reset(mapping, (HttpServletRequest) request); } catch (ClassCastException e) { ; } } /** * Reset all bean properties to their default state. This method is * called before the properties are repopulated by the controller servlet. *
* The default implementation does nothing. Subclasses should override * this method to reset all bean properties to default values. *
** This method is not the appropriate place to initialize form values * for an "update" type page (this should be done in a setup Action). You mainly * need to worry about setting checkbox values to false; most of the time you * can leave this method unimplemented. *
* * @param mapping The mapping used to select this instance * @param request The servlet request we are processing */ public void reset(ActionMapping mapping, HttpServletRequest request) { ; // Default implementation does nothing } /** * Validate the properties that have been set for this non-HTTP request, * and return anActionErrors object that encapsulates any
* validation errors that have been found. If no errors are found, return
* null or an ActionErrors object with no
* recorded error messages.
*
* The default implementation attempts to forward to the HTTP version of
* this method.
*
* @param mapping The mapping used to select this instance
* @param request The servlet request we are processing
*/
public ActionErrors validate(ActionMapping mapping,
ServletRequest request) {
try {
return (validate(mapping, (HttpServletRequest) request));
} catch (ClassCastException e) {
return (null);
}
}
/**
* Validate the properties that have been set for this HTTP request,
* and return an ActionErrors object that encapsulates any
* validation errors that have been found. If no errors are found,
* return null or an ActionErrors object with
* no recorded error messages.
*
* The default ipmlementation performs no validation and returns
* null. Subclasses must override this method to provide
* any validation they wish to perform.
*
* @param mapping The mapping used to select this instance
* @param request The servlet request we are processing
*/
public ActionErrors validate(ActionMapping mapping,
HttpServletRequest request) {
return (null);
}
}