RE: [****] Including a Struts action in a JSP - IllegalStateException / truncated response issue
Thanks for your help David. This is very informative and confirms many of my suspicions. My perspective on the issue is this. I can understand the technical constraints on including a Struts action in a JSP given the design (though, oddly this seems to work fairly well if you do it only once per JSP). On the technical side, I've resigned to using absolute URLs with to prevent response building conflicts when including multiple Struts actions on one JSP. But when we're talking about good, decoupled architecture, does it not make sense to keep various functions independent of one another by giving them their own Struts action and their own JSP? If an action is responsible _only_ for knowing what data to retrieve from the model and _always_ passing that data on to its own view aren't we decoupling better (for ease of reuse and simplicity of architecture) than we could with inheritance and chaining? Is there any reason why Struts could not support this in some future release? - Jeff -Original Message- From: David G. Friedman [mailto:[EMAIL PROTECTED] Sent: Monday, November 08, 2004 11:40 PM To: Parke Jeff; Struts Users Mailing List Subject: RE: [] Including a Struts action in a JSP - IllegalStateException / truncated response issue Jeff, I have an odd idea why you are having your problem. In the first request included below you wrote: > I'm still having trouble including a Struts action > into a JSP (). Trying to import a struts action is likely the cause of your problem. Any action called after another action forces the whole ActionServlet processing to begin again. So you are parsing the request in your original action and going to a JSP, that JSP sets any final headers and sends them to the client and WHAM you force Struts to try to do that AGAIN on an output stream that has already begin being sent to the client. Your import of an action tries to perform the whole process again, including setting headers (BOOM!) and your code goes haywire at this point. Chaining actions inside the Server (unless you send redirects to the client) isn't an efficient way to do multiple setups. There have been plenty of discussion threads about having an action invoking another action as it's "success" ActionForward mapping and how that reprocesses the input again and can reset any data in the bean (if both Actions use the same bean) back to the submitted ones EVEN IF they were changed whiel being processed by the first Action. One key spec you noted in your original request: > 2) To be able to include one or more > Struts actions in any given JSP (ie: > ). A better way, than chaining actions or trying to import output from another (BOOM!) action, would be to have either a base Action subclass of your own or common code that all actions invoke which would: A. Decide what beans to populate and the names used to save them in scope (probably request scope). B. Decide what JSP's to include in your tile and in what order so it can display the data saved in step "A" above. Tiles has a "putList" feature which can cause JSP's to be inserted into a section of a tile template. See the Tiles Advanced Features PDF I mentioned in a previous email, chapter 6.4.2. That section is simply an example of putList with JSPs. If you do not like the idea of making a base Action class of your own to subclass for all of your Actions, you could move the A/B steps coding into a subclass of RequestProcessor (or TilesRequestProcessor) so the processing occurs for all Actions and you can then use standard Action classes for your site. Or, you could go wild & crazy and try Struts Chains to see if that fits. Regards, David -Original Message- From: Parke Jeff [mailto:[EMAIL PROTECTED] Sent: Monday, November 08, 2004 9:41 AM To: David G. Friedman; Struts Users Mailing List Subject: RE: [] Including a Struts action in a JSP - IllegalStateException / truncated response issue Thanks for the information guys. I actually have tried upping the response buffer size in a variety of places (JSP, Struts action, application server configuration) but it didn't fix the problem for me. As for ensuring that the headers aren't messed with in the included resource (JSP/Struts action), I don't know that this is easy to do. I can tell you that I do not believe I am doing any operation that would cause a change to the response headers. However, I have read that simply performing an include can cause a response to be committed and subsequently performing a forward (using ActionForward) can cause an IllegalStateException. I don't really understand this, both conceptually and based on experiment but it seems to be inconsistently true nonetheless. It seems that the first include of a Struts action goes through fine (usually, sometimes truncated buffer), but the second or third include of a Struts action (
RE: [****] Including a Struts action in a JSP - IllegalStateException / truncated response issue
Thanks for the information guys. I actually have tried upping the response buffer size in a variety of places (JSP, Struts action, application server configuration) but it didn't fix the problem for me. As for ensuring that the headers aren't messed with in the included resource (JSP/Struts action), I don't know that this is easy to do. I can tell you that I do not believe I am doing any operation that would cause a change to the response headers. However, I have read that simply performing an include can cause a response to be committed and subsequently performing a forward (using ActionForward) can cause an IllegalStateException. I don't really understand this, both conceptually and based on experiment but it seems to be inconsistently true nonetheless. It seems that the first include of a Struts action goes through fine (usually, sometimes truncated buffer), but the second or third include of a Struts action (for me) causes an IllegalStateException. Anyway, I've been able to skirt the issue by using absolute URLs in my statement, a trick which seems to bypass the include operation's commit of the response. This is far from ideal as the request scope is different between the included resource and the calling one, so I'm still very interested in help finding out whether my issues are common, whether they should be considered symptoms of a bug, and whether there is a cleaner workaround that the one described above. Have a look at my original post, which got lost in the thread, for more background and related resources: http://marc.theaimsgroup.com/?l=struts-user&m=109942705229329&w=2 Thanks again, Jeff -Original Message- From: David G. Friedman [mailto:[EMAIL PROTECTED] Sent: Friday, November 05, 2004 6:18 PM To: Struts Users Mailing List Subject: RE: [] Including a Struts action in a JSP - IllegalStateException / truncated response issue Jeff, Try this previous post on IllegalStateException response has already been committed: http://marc.theaimsgroup.com/?l=struts-user&m=108152145227595&w=2 The author suggested 2 courses of action: 1. Try increasing the buffer size on myjsp.jsp. Default is 8kb 2. Make sure that you are not changing the header portion of the response in your included JSP page. I remember a post with the same exception and the issue was a buffer issue. Regards, David -Original Message- From: Parke Jeff [mailto:[EMAIL PROTECTED] Sent: Friday, November 05, 2004 11:28 AM To: [EMAIL PROTECTED] Cc: Struts Users Mailing List Subject: Re: [] Including a Struts action in a JSP - IllegalStateException / truncated response issue Thanks for the information, Jeff. Unfortunately, though the Tiles Advanced Features Guide indicates it is possible to include multiple Struts actions (using ) on one page, I _still_ get the IllegalStateException Response has already been committed. "We often need to prepare data to be shown by a JSP page. In the MVC framework, the controller prepares data (in the model) to be shown by the view. Translated to Tiles and Struts, we can use a Struts Action as a controller, a JSP page as a view, and combine both in a Tile. So, when you insert the Tile, the Action is called before the JSP page is displayed. Now, your complex web page can be made of Tiles fed by controllers (one sub-controller for each Tile). This approach is better than one single controller for all Tiles of the page, because it really allows building autonomous Tiles, without worrying about how to fed (sic) them all." - Tiles Advanced Features Guide (http://www.lifl.fr/~dumoulin/tiles/tilesAdvancedFeatures.pdf) This is describing exactly what I want to accomplish and the reason for it but I keep running into the same committed response problem. Is it possible that this is a container issue rather than being a Struts issue? Can someone else confirm that and both cause an IllegalStateException when including more than 1 (actually try 3 or 4) Struts action on the same JSP? Thanks again for anyone who can help, Jeff I think that it is unusual to directly include Struts actions in JSP files. When composing pages of different parts, Tiles is the much more common approach. The standard usage of Tiles is to include JSP files directly, but you can use tiles to include Struts actions in JSP files. (See Section 5.2 of the Tiles Advanced Features guide, a PDF file, at http://www.lifl.fr/~dumoulin/tiles/tilesAdvancedFeatures.pdf.) -- Jeff ---- Parke Jeff wrote: I'm still having trouble including a Struts action into a JSP (). I've tried using absolute URLs, passing the jsessionid to ensure that the session is not lost, but the request context is different between the JSP and the included action, so this not suitable for many situations. I've also tried upgrading to Struts 1
Re: [****] Including a Struts action in a JSP - IllegalStateException / truncated response issue
Thanks for the information, Jeff. Unfortunately, though the Tiles Advanced Features Guide indicates it is possible to include multiple Struts actions (using ) on one page, I _still_ get the IllegalStateException Response has already been committed. "We often need to prepare data to be shown by a JSP page. In the MVC framework, the controller prepares data (in the model) to be shown by the view. Translated to Tiles and Struts, we can use a Struts Action as a controller, a JSP page as a view, and combine both in a Tile. So, when you insert the Tile, the Action is called before the JSP page is displayed. Now, your complex web page can be made of Tiles fed by controllers (one sub-controller for each Tile). This approach is better than one single controller for all Tiles of the page, because it really allows building autonomous Tiles, without worrying about how to fed (sic) them all." - Tiles Advanced Features Guide (http://www.lifl.fr/~dumoulin/tiles/tilesAdvancedFeatures.pdf) This is describing exactly what I want to accomplish and the reason for it but I keep running into the same committed response problem. Is it possible that this is a container issue rather than being a Struts issue? Can someone else confirm that and both cause an IllegalStateException when including more than 1 (actually try 3 or 4) Struts action on the same JSP? Thanks again for anyone who can help, Jeff I think that it is unusual to directly include Struts actions in JSP files. When composing pages of different parts, Tiles is the much more common approach. The standard usage of Tiles is to include JSP files directly, but you can use tiles to include Struts actions in JSP files. (See Section 5.2 of the Tiles Advanced Features guide, a PDF file, at http://www.lifl.fr/~dumoulin/tiles/tilesAdvancedFeatures.pdf.) -- Jeff ---- Parke Jeff wrote: I'm still having trouble including a Struts action into a JSP (). I've tried using absolute URLs, passing the jsessionid to ensure that the session is not lost, but the request context is different between the JSP and the included action, so this not suitable for many situations. I've also tried upgrading to Struts 1.2.4. This does not resolve the "Response has already been committed" issue when including more than one Struts action in a JSP. The app server is using JRE 1.4.1_03-b02. Can anyone tell me whether they have seen this situation before? How common is it? Is it unusual to include Struts actions in JSPs? Anyone? Thanks, Jeff - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
RE: [****] Including a Struts action in a JSP - IllegalStateException / truncated response issue
I'm still having trouble including a Struts action into a JSP (). I've tried using absolute URLs, passing the jsessionid to ensure that the session is not lost, but the request context is different between the JSP and the included action, so this not suitable for many situations. I've also tried upgrading to Struts 1.2.4. This does not resolve the "Response has already been committed" issue when including more than one Struts action in a JSP. The app server is using JRE 1.4.1_03-b02. Can anyone tell me whether they have seen this situation before? How common is it? Is it unusual to include Struts actions in JSPs? Anyone? Thanks, Jeff -Original Message- From: Parke Jeff Sent: Tuesday, November 02, 2004 3:23 PM To: [EMAIL PROTECTED] Subject: [] Including a Struts action in a JSP - IllegalStateException / truncated response issue Hello, I've seen a few posts on this subject, through this and other resources, but I haven't seen any appealing workarounds. I'd like to try to bring all the relevant information from these posts together and then ask for help in identifying a viable workaround. I apologize in advance if this issue is well known and understood and I just missed the best resources on the subject. Goals: 1) To build a Struts application where _every_ request to the application goes through a Struts action that collects and packages data then forwards (using Struts ActionForward's) to a JSP. 2) To be able to include one or more Struts actions in any given JSP (ie: ). Behavior when implementing these goals: 1) Usually, when executing a single include of a Struts action on a JSP, everything works fine though sometimes there are problems (as listed below). 2) When including more than one Struts action on a JSP I get an IllegalStateException - Response has already been committed. 3) Sometimes, when a JSP only includes one Struts action, the first x bytes of the response will be missing when it is returned (without exception) to the client. Relevant issues (correct me where I'm wrong): 1) Including (, , etc.) a JSP/Servlet on a JSP sometimes (always?) causes the response to be committed because includes use RequestDispatcher.include() which in turn commits the response. 2) Forwarding a request using an ActionForward from a Struts action to a JSP can not be done when a response has been committed. 3) Increasing the response buffer size has no effect on these issues. 4) Using the include directive (<%@ include file="filename" %>) won't work because that includes source a translation time. 5) It has been reported that using does not (fully/always?) resolve the problematic behavior. 6) Using absolute URLs with prevents the response from being committed because the context of the request is assumed to be independent. The visibility of an authenticated, populated session can be affected by passing the jsessionid in on the URL. This seems to be the only viable workaround though I haven't tested it thoroughly yet. Reference: http://www.mail-archive.com/[EMAIL PROTECTED]/msg13284.html http://www.jguru.com/faq/view.jsp?EID=501393 http://www.mail-archive.com/[EMAIL PROTECTED]/msg05711.htm l http://www.mail-archive.com/[EMAIL PROTECTED]/msg15194.html http://forum.java.sun.com/thread.jsp?thread=484731&forum=45&message=2266 277 http://www.mail-archive.com/[EMAIL PROTECTED]/msg15189.html http://jguru.com/forums/view.jsp?EID=1204797 http://forum.java.sun.com/thread.jsp?thread=461644&forum=45&message=2115 900 http://www.mail-archive.com/[EMAIL PROTECTED]/msg18018.html http://www.mail-archive.com/[EMAIL PROTECTED]/msg74816.html http://www.mail-archive.com/[EMAIL PROTECTED]/msg29073.html My setup: - Oracle AS 10g (OC4J) app server - Struts 1.1 - JSTL 1.0.6 Is there any clean way to meet the two goals listed above without error? Thanks, Jeff - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Including a Struts action in a JSP - IllegalStateException / truncated response issue
Hello, I've seen a few posts on this subject, through this and other resources, but I haven't seen any appealing workarounds. I'd like to try to bring all the relevant information from these posts together and then ask for help in identifying a viable workaround. I apologize in advance if this issue is well known and understood and I just missed the best resources on the subject. Goals: 1) To build a Struts application where _every_ request to the application goes through a Struts action that collects and packages data then forwards (using Struts ActionForward's) to a JSP. 2) To be able to include one or more Struts actions in any given JSP (ie: ). Behavior when implementing these goals: 1) Usually, when executing a single include of a Struts action on a JSP, everything works fine though sometimes there are problems (as listed below). 2) When including more than one Struts action on a JSP I get an IllegalStateException - Response has already been committed. 3) Sometimes, when a JSP only includes one Struts action, the first x bytes of the response will be missing when it is returned (without exception) to the client. Relevant issues (correct me where I'm wrong): 1) Including (, , etc.) a JSP/Servlet on a JSP sometimes (always?) causes the response to be committed because includes use RequestDispatcher.include() which in turn commits the response. 2) Forwarding a request using an ActionForward from a Struts action to a JSP can not be done when a response has been committed. 3) Increasing the response buffer size has no effect on these issues. 4) Using the include directive (<%@ include file="filename" %>) won't work because that includes source a translation time. 5) It has been reported that using does not (fully/always?) resolve the problematic behavior. 6) Using absolute URLs with prevents the response from being committed because the context of the request is assumed to be independent. The visibility of an authenticated, populated session can be affected by passing the jsessionid in on the URL. This seems to be the only viable workaround though I haven't tested it thoroughly yet. Reference: http://www.mail-archive.com/[EMAIL PROTECTED]/msg13284.html http://www.jguru.com/faq/view.jsp?EID=501393 http://www.mail-archive.com/[EMAIL PROTECTED]/msg05711.htm l http://www.mail-archive.com/[EMAIL PROTECTED]/msg15194.html http://forum.java.sun.com/thread.jsp?thread=484731&forum=45&message=2266 277 http://www.mail-archive.com/[EMAIL PROTECTED]/msg15189.html http://jguru.com/forums/view.jsp?EID=1204797 http://forum.java.sun.com/thread.jsp?thread=461644&forum=45&message=2115 900 http://www.mail-archive.com/[EMAIL PROTECTED]/msg18018.html http://www.mail-archive.com/[EMAIL PROTECTED]/msg74816.html http://www.mail-archive.com/[EMAIL PROTECTED]/msg29073.html My setup: - Oracle AS 10g (OC4J) app server - Struts 1.1 - JSTL 1.0.6 Is there any clean way to meet the two goals listed above without error? Thanks, Jeff
