we want to have and execute(...) method in a abstract class so that we could through exceptions other than the ones perform(...) could throw? is it correct?
ATTA ----- Original Message ----- From: "Trieu, Danny" <[EMAIL PROTECTED]> To: "'Struts Users Mailing List'" <[EMAIL PROTECTED]> Sent: Monday, November 18, 2002 2:05 PM Subject: RE: Howto handle this behavior in Struts+Tiles > Okay, > > If you want to handle where to go next in one place then create the abstract > class and have > All the exception handling extends from it. All the handler action need to > do is to do profiling > Of the exception, and the abstract class's perform(...) will catch the > exceptions handle it or > Just forward it to the associated VIEW. This works too, if you want all of > your action > Extends from this abstract action, if this is the case you want, which I > would prefer, then > You might want your abstract class to handle the exception, meaning you want > the abstract class > To catch it, profile/log the exception and then forwad to the VIEW. If this > is the case then > Your exception handler action doesn't have to do anything but throw the > correct exception so the > Abstract action class will catch it and handle it for you. > > If you are looking at this clearly, what we want to do is to create a > template of execution at > The base of all your application exceptions to handle different kind of > exceptions. And since > We can only do this if exception being throw inside of the execution context > of a dispatched > Action class, exceptions that might happen in the VIEW, the original problem > that init our > Conversation, will not get handled. And so if we want it to be control in > one place then what > Should we do? Ahah.. We use the web.xml exception mapping to do the work. > Meaning, we use > The web.xml exception mapping to map all the exceptions that happen outside > of the Action's > Execution context back into an Action mapping with in turns will re throw it > so that the > Exception is now within the Action's execution context. There is many > different way to do > This, and it all depends on the need of your application. This just an idea > or should I say > Concept of how to handle exceptions and errors within a web application. > > If you implement this with Struts and Tiles, then is no need for using the > conventional JSP's > Page directive to handle error. There is a few reasons why I don't like > this is error handling > Logic are coupling with JSPs every where and it is hard to manage and reuse. > Where as if you > Follow my approach, you can pretty much go to one or two place to see how > all the error being > Handled, and if you decided to reuse it all that is need to do is to modify > your strusts-config.xml, > Web.xml and Wala... You have it up runing. > > Let me know if anything else I can help you with ... :) > > --danny > > Ps. Don't know how advance this technique is, but I do hope that Chuck > Struts book, and Ted/Credic/..'s > Struts book mention about best practice of handling erro and exception > within web application. > > -----Original Message----- > From: atta ur-rehman [mailto:[EMAIL PROTECTED]] > Sent: Monday, November 18, 2002 1:22 PM > To: Struts Users Mailing List > Subject: Re: Howto handle this behavior in Struts+Tiles > > > Hi Danny, > > I'm confused already!!! > > here is the abstract action class with an abstract execute method: > > -------------------------------------------------------------------------- - > import javax.servlet.http.*; > import org.apache.struts.action.*; > > public abstract class AbstractErrorHandlerAction extends Action { > > public abstract void execute(ActionMapping mapping, ActionForm form, > HttpServletRequest request , HttpServletResponse response) throws > Exception; } > -------------------------------------------------------------------------- - > > now should all my actions extend this class? or its only the action handler > action that would extend this class? moreover, I don't see throws clause in > the perform(...) method of Action class? > > So, am I completely lost? I hope you won't mind my simplistic questions!!! > > ATTA > > ----- Original Message ----- > From: "Trieu, Danny" <[EMAIL PROTECTED]> > To: "'Struts Users Mailing List'" <[EMAIL PROTECTED]> > Sent: Monday, November 18, 2002 1:05 PM > Subject: RE: Howto handle this behavior in Struts+Tiles > > > > I thinks so ... > > > > Good luck...:) > > > > --danny > > > > -----Original Message----- > > From: atta ur-rehman [mailto:[EMAIL PROTECTED]] > > Sent: Monday, November 18, 2002 1:05 PM > > To: Struts Users Mailing List > > Subject: Re: Howto handle this behavior in Struts+Tiles > > > > > > okay, let me give it a try and I'll get back to you! thanks. > > > > by the way, do you if this feature is available thru servlet 2.2 > > specs? > > > > ATTA > > > > > > ----- Original Message ----- > > From: "Trieu, Danny" <[EMAIL PROTECTED]> > > To: "'Struts Users Mailing List'" <[EMAIL PROTECTED]> > > Sent: Monday, November 18, 2002 11:54 AM > > Subject: RE: Howto handle this behavior in Struts+Tiles > > > > > > > You are almost close ... :) Yes my point 3 is that mapping in the > > > web.xml. But Instead of going to the JSP, > > > <location>/ErrorPage.jsp</location>, you > > would > > > want > > > To go to <location>/errors/catchError.do</location>, which map it to > > > a Action that You extended from your abstract action class. This > > > action would do all > > the > > > necessary > > > Stuff with your Exception if there is one or create a new exception > > > and throw it. > > > > > > --danny > > > > > > -----Original Message----- > > > From: atta ur-rehman [mailto:[EMAIL PROTECTED]] > > > Sent: Monday, November 18, 2002 11:42 AM > > > To: Struts Users Mailing List > > > Subject: Re: Howto handle this behavior in Struts+Tiles > > > > > > > > > Hi, > > > > > > This definitely is helpful. As I'm not very experiences in Struts, > > > does > > your > > > point 3 refers to > > > > > > <error-page> > > > <exception-type>java.lang.Exception</exception-type> > > > <location>/ErrorPage.jsp</location> > > > </error-page> > > > > > > construct in "web.xml" or is it something different? If its the same > > thing, > > > how do I know if my JSP container supports this feature or not. I'm > > > asking this because we are running ServletExec 3.1 that is compliant > > > to Servlet > > 2.2 > > > only. > > > > > > Thanks. > > > > > > ATTA > > > > > > > > > ----- Original Message ----- > > > From: "Trieu, Danny" <[EMAIL PROTECTED]> > > > To: "'Struts Users Mailing List'" <[EMAIL PROTECTED]> > > > Sent: Monday, November 18, 2002 11:15 AM > > > Subject: RE: Howto handle this behavior in Struts+Tiles > > > > > > > > > > Hello, > > > > > > > > 1.0 doesn't support declarative exception handling, but it doesn't > > > > prevent you from Doing so...:) Anyway, what I would do is: 1) > > > > Implement an abstract Action have and Abstract method execute(...) > > > > throw Exception. 2) Implement the > > > perform(...) > > > > method > > > > That will call you're the abstract excecute(...) method, and catch > > > > all or any specific Exception and return the associated forward to > > > > the specific View(JSP) as needed. > > > > 3) Map all/any error-code and exception mapping in your web.xml to > > > > an > > > Action > > > > that > > > > Extended from your abstract exception. This exception can be > > > > generic or specific to A particular mapping, it will profile the > > > > exception and re-throw or create > > > a > > > > new exception > > > > And throw it, so that the perform method will catch this exception > > > > and > > > route > > > > it to the > > > > Targeted VIEW. > > > > > > > > Hope this would help, > > > > > > > > --danny > > > > > > > > -----Original Message----- > > > > From: atta ur-rehman [mailto:[EMAIL PROTECTED]] > > > > Sent: Monday, November 18, 2002 10:57 AM > > > > To: Struts Users Mailing List > > > > Subject: Re: Howto handle this behavior in Struts+Tiles > > > > > > > > > > > > Thanks, Danny, for the detailed response. > > > > We're running Struts 1.0.x. Does it support ExceptionHandler > > > > paradigm? If > > > so > > > > could you please point towards some starting points. > > > > > > > > Thanks again. > > > > > > > > ATTA > > > > > > > > > > > > ----- Original Message ----- > > > > From: "Trieu, Danny" <[EMAIL PROTECTED]> > > > > To: "'Struts Users Mailing List'" <[EMAIL PROTECTED]> > > > > Cc: "Mebed, Waheed" <[EMAIL PROTECTED]> > > > > Sent: Monday, November 18, 2002 10:36 AM > > > > Subject: RE: Howto handle this behavior in Struts+Tiles > > > > > > > > > > > > > Hello, > > > > > > > > > > Usually exception that being thrown by the VIEW(JSP) are > > > > > rendering related exception. This could be tags/Scriptlet that > > > > > access resource, JavaBeans, fails. Meaning the Resource is not > > > > > there. And when these thing happen with composite view thing > > > > > became A bit tricky. First of all, within the container, the > > > > > layout, of the composite view You don't where exception might be > > > > > thrown. Second, the page directive > > > for > > > > > 'errorPage' > > > > > Can only be set at the outter most container, the layou, and not > > > > > within > > > > any > > > > > of its > > > > > Contained JSP. Since, you never know when response has been > > > > > committed to the client Browser. And if response has already > > > > > committed to the clien browser, any attemp to Forward to a > > > > > different resource is an IllegalStateException. A quick > > > > > solution to your Problem is to only have the page directive for > > > > > your JSP is in the > > outer > > > > most > > > > > container, > > > > > The layout. > > > > > > > > > > My approach to handling the front-end exception in Struts1+ is > > > > > having a sub-module for Handling exception with a set of custom > > > > > or generic ExceptionHandler, with action mapping That will > > > > > capture the exception, do exception profiling or anything > > > > > neccessarry, and use Struts declarative exception handling to > > > > > map it to a user friendly > > View > > > > for > > > > > displaying > > > > > Specific error pages. This has to work with the Web application > > > > > error mapping in the Web.xml deployment descriptor, to map > > > > > different error-code and exception > > > > to > > > > > the right > > > > > Action mapping in your exception sub-module that will handle the > > > > exception. > > > > > I think > > > > > This is a much cleaner way to haddle exception since it promote > > > > > encapsulation of exception Handling into one central place, the > > > > > sub-module, that can be manage easily and consistent Through out > > > > > the entire application. Plus, exception handler can be > > > reused > > > > > in different > > > > > Web application with the entire enterprise. > > > > > > > > > > Hope this would help, > > > > > > > > > > -danny > > > > > > > > > > -----Original Message----- > > > > > From: atta ur-rehman [mailto:[EMAIL PROTECTED]] > > > > > Sent: Monday, November 18, 2002 9:52 AM > > > > > To: struts users mailing list > > > > > Subject: Howto handle this behavior in Struts+Tiles > > > > > > > > > > > > > > > Dear all, > > > > > > > > > > Here is my "layout.jsp" file: > > > > > > > > > > <%@ page errorPage="ErrorPage.jsp" %> > > > > > > > > > > <tiles:insert attribute="menu"/> > > > > > <tiles:insert attribute="body"/> > > > > > <tiles:insert attribute="footer"/> > > > > > > > > > > The "menu" tile is a JSP page that could throw an exception. Now > > > > > whenever > > > > an > > > > > exception is thrown on the "menu" tile I want to goto JSP Error > > > > > Page. What > > > > I > > > > > get instead is this exception: > > > > > > > > > > [Exception in:/main-menu.jsp] reset() failed - data has already > > > > > been sent > > > > to > > > > > client java.lang.IllegalStateException: reset() failed - data > > > > > has already been sent to client. > > > > > > > > > > Could you please help me with this one? What do I need to fix > > > > > this > > > > problem. > > > > > By the way "menu.jsp" contains <%@ page > > > > > errorPage="ErrorPage.jsp" %> directive. And currently if there > > > > > is an exception on "layout.jsp" Error > > > > Page > > > > > does show up with appropriate error message. > > > > > > > > > > TIA, > > > > > > > > > > ATTA > > > > > > > > > > > > > > > -- > > > > > To unsubscribe, e-mail: > > > > <mailto:[EMAIL PROTECTED]> > > > > > For additional commands, e-mail: > > > > <mailto:[EMAIL PROTECTED]> > > > > > > > > > > > > > > > > > > > > > > -- > > > > To unsubscribe, e-mail: > > > > <mailto:[EMAIL PROTECTED]> > > > > For additional commands, e-mail: > > > > <mailto:[EMAIL PROTECTED]> > > > > > > > > -- > > > > To unsubscribe, e-mail: > > > <mailto:[EMAIL PROTECTED]> > > > > For additional commands, e-mail: > > > <mailto:[EMAIL PROTECTED]> > > > > > > > > > > > > > > > > > -- > > > To unsubscribe, e-mail: > > > <mailto:[EMAIL PROTECTED]> > > > For additional commands, e-mail: > > > <mailto:[EMAIL PROTECTED]> > > > > > > -- > > > To unsubscribe, e-mail: > > <mailto:[EMAIL PROTECTED]> > > > For additional commands, e-mail: > > <mailto:[EMAIL PROTECTED]> > > > > > > > > > > > > -- > > To unsubscribe, e-mail: > > <mailto:[EMAIL PROTECTED]> > > For additional commands, e-mail: > > <mailto:[EMAIL PROTECTED]> > > > > -- > > To unsubscribe, e-mail: > <mailto:[EMAIL PROTECTED]> > > For additional commands, e-mail: > <mailto:[EMAIL PROTECTED]> > > > > > > > > > -- > To unsubscribe, e-mail: > <mailto:[EMAIL PROTECTED]> > For additional commands, e-mail: > <mailto:[EMAIL PROTECTED]> > > -- > To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> > For additional commands, e-mail: <mailto:[EMAIL PROTECTED]> > > -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
