Iterate the action? Oh I thought the second time you ran through it was after the user had submitted the form, at least that was the impression I had got from the comments in the code: <snip> else if (formBean.isBlnUpdateAction()) // user clicks 'update' in "first.jsp", Run through this Action class the 2nd time </snip>
No idea then. Unless you mean by 'iterate' future invokations of the same action from new requests? (Thats not what I understand by the term iterate...) In this case what you need to remember is that the lifetime of a request is only the processing of that request. Ie - request (GET or POST) comes in from the browser, the container creates an HttpServletRequest object that encapsulates the information in the request, processes the request (sends it the the ActionServlet where it is processed by your action and perhaps forwards to further resources (most notably the jsp) to be handled). The processing of the request having been completed, response writing etc... , that HttpServletRequest object goes out of scope. Future (and indeed simultaneous) requests from browsers will get their own HttpServletRequest objects. The request attributes set is tied to a single request object and when that object goes out of scope obviously you cant get at its attributes anymore (unless you have some other reference to them of course) - and this is why you often hear people say things like "put the object into request scope...". If you need to share and keep track of stuff across multiple requests (and threads) then you may use the session or servlet context objects for this. -----Original Message----- From: Au-Yeung, Stella H [mailto:[EMAIL PROTECTED] Sent: Thursday, 17 July 2003 12:24 To: 'Struts Users Mailing List' Subject: RE: Request object Null Pointer I thought once I store an attribute into the 'request' object, it will be available no matter how many times I iterate through the same Action class? If it doesn't do that, then how do I store data into the request object so I can use it again later in the same Action class or even in a different Action class. Thx. -----Original Message----- From: Andrew Hill [mailto:[EMAIL PROTECTED] Sent: Thursday, July 17, 2003 12:06 AM To: Struts Users Mailing List Subject: RE: Request object Null Pointer Well of course its null. The second time through you arent calling request.setAttribute("vehList",vehList) before calling prepareListForUpdate() -----Original Message----- From: Au-Yeung, Stella H [mailto:[EMAIL PROTECTED] Sent: Thursday, 17 July 2003 10:52 To: '[EMAIL PROTECTED]' Subject: Request object Null Pointer Hi: I am getting a NULL pointer with the request object: Please see code below. I got a NULL pointer trying to access "vehList' in the request object inside the method "prepareListForUpdate". But I didn't get a NULL pointer accessing "vehList" inside the method "setScheduleList". So it looks like the 1st time it ran through the Action class, the request object is ther. But the 2nd time it ran through the Action class, either the request object is null or "vehList' is no longer in the request object. =============================== Portion of Action class: ArrayList vehList = new ArrayList(); ==> initialize and set values for vehList here <==== if (formBean.isSearchAction()) // user clicks 'search' on form. Run through this Action class the 1st time { request.setAttribute("vehList",vehList); this.setScheduleList(request); // invoke another method <=== eventually "first.jsp" with an 'Update" button is displayed } else if (formBean.isBlnUpdateAction()) // user clicks 'update' in "first.jsp", Run through this Action class the 2nd time { this.prepareListForUpdate(request); // invoke another method } ============================= Portion of method "setScheduleList": setScheduleList(javax.servlet.http.HttpServletRequest request) { // display vehList.size() AND IT PRINTED OUT OK ArrayList l = (ArrayList) request.getAttribute("vehList"); EtLog.debug(this,"in setScheduleList, vehList,size()="+l.size()); } ================================== Portion of method "prepareListForUpdate": prepareListForUpdate(javax.servlet.http.HttpServletRequest request) { // display vehList.size() AND IT GAVE ME A NULL POINTER EXCEPTION ArrayList l = (ArrayList) request.getAttribute("vehList"); EtLog.debug(this,"in prepareListForUpdate, vehList,size()="+l.size()); } ==================================== Any help will be appreciated, Newbie --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
