Re: Help with chaining servlets via filters
On Tue, 23 Jul 2002, John Rishea wrote: Date: Tue, 23 Jul 2002 06:33:57 -0600 From: John Rishea [EMAIL PROTECTED] Reply-To: Tomcat Users List [EMAIL PROTECTED] To: Tomcat User Group [EMAIL PROTECTED] Subject: Help with chaining servlets via filters Could someone please point me toward a good resource that shows an example of chaining two servlets using a filter? I've found lots of filter examples during my google searches but none of them shows exactly how to chain two servlets together with a filter. What are you trying to accomplish by chaining two servlets using a filter? The traditional definition of servlet chaining (feeding the output of one servlet into another) has turned out to be a very bad design pattern, so it's not supported. On the other hand, filters themselves can modify input on the way in, and output on the way out. And you can easily configure more than one filter to be mapped to a particular request. It all comes down to what you are trying to accomplish. Thanks for the help. __ John Rishea Craig -- To unsubscribe, e-mail: mailto:[EMAIL PROTECTED] For additional commands, e-mail: mailto:[EMAIL PROTECTED]
RE: Help with chaining servlets via filters
Craig, I have one servlet that runs a unix script using runtime exec to create an output file, then a follow-up servlet that takes the output file and displays it to a browser window. The servlets work fine separately but don't work when combined into a single servlet. So I was looking for a way to call the display servlet immediately after the script-running servlet does its thing. Any constructive suggestions would be appreciated. __ John Rishea -Original Message- From: Craig R. McClanahan [mailto:[EMAIL PROTECTED]] Sent: Tuesday, July 23, 2002 9:47 AM To: Tomcat Users List Subject: Re: Help with chaining servlets via filters On Tue, 23 Jul 2002, John Rishea wrote: Date: Tue, 23 Jul 2002 06:33:57 -0600 From: John Rishea [EMAIL PROTECTED] Reply-To: Tomcat Users List [EMAIL PROTECTED] To: Tomcat User Group [EMAIL PROTECTED] Subject: Help with chaining servlets via filters Could someone please point me toward a good resource that shows an example of chaining two servlets using a filter? I've found lots of filter examples during my google searches but none of them shows exactly how to chain two servlets together with a filter. What are you trying to accomplish by chaining two servlets using a filter? The traditional definition of servlet chaining (feeding the output of one servlet into another) has turned out to be a very bad design pattern, so it's not supported. On the other hand, filters themselves can modify input on the way in, and output on the way out. And you can easily configure more than one filter to be mapped to a particular request. It all comes down to what you are trying to accomplish. Thanks for the help. __ John Rishea Craig -- 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]
RE: Help with chaining servlets via filters
http://www.javaworld.com/javaworld/jw-06-2001/jw-0622-filters.html Jacob Hookom Comprehensive Computer Science University of Wisconsin, Eau Claire -Original Message- From: Craig R. McClanahan [mailto:[EMAIL PROTECTED]] Sent: Tuesday, July 23, 2002 10:47 AM To: Tomcat Users List Subject: Re: Help with chaining servlets via filters On Tue, 23 Jul 2002, John Rishea wrote: Date: Tue, 23 Jul 2002 06:33:57 -0600 From: John Rishea [EMAIL PROTECTED] Reply-To: Tomcat Users List [EMAIL PROTECTED] To: Tomcat User Group [EMAIL PROTECTED] Subject: Help with chaining servlets via filters Could someone please point me toward a good resource that shows an example of chaining two servlets using a filter? I've found lots of filter examples during my google searches but none of them shows exactly how to chain two servlets together with a filter. What are you trying to accomplish by chaining two servlets using a filter? The traditional definition of servlet chaining (feeding the output of one servlet into another) has turned out to be a very bad design pattern, so it's not supported. On the other hand, filters themselves can modify input on the way in, and output on the way out. And you can easily configure more than one filter to be mapped to a particular request. It all comes down to what you are trying to accomplish. Thanks for the help. __ John Rishea Craig -- To unsubscribe, e-mail: mailto:[EMAIL PROTECTED] For additional commands, e-mail: mailto:[EMAIL PROTECTED] --- Incoming mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.375 / Virus Database: 210 - Release Date: 7/10/2002 --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.375 / Virus Database: 210 - Release Date: 7/10/2002 -- To unsubscribe, e-mail: mailto:[EMAIL PROTECTED] For additional commands, e-mail: mailto:[EMAIL PROTECTED]
RE: Help with chaining servlets via filters
On Tue, 23 Jul 2002, John Rishea wrote: Date: Tue, 23 Jul 2002 10:09:50 -0600 From: John Rishea [EMAIL PROTECTED] Reply-To: Tomcat Users List [EMAIL PROTECTED] To: Tomcat Users List [EMAIL PROTECTED] Subject: RE: Help with chaining servlets via filters Craig, I have one servlet that runs a unix script using runtime exec to create an output file, then a follow-up servlet that takes the output file and displays it to a browser window. The servlets work fine separately but don't work when combined into a single servlet. So I was looking for a way to call the display servlet immediately after the script-running servlet does its thing. Any constructive suggestions would be appreciated. Why can't you just modify the servlet that runs the unix script to copy the output back to the client after the script executes? If the second servlet needs to perform modifications in the output format (such as converting static text into HTML, or performing an XSLT transformation on an XML file), that's the kind of things that a Filter is for. Search Google and java.sun.com for filter and you'll find lots of tutorials, resources, and examples of how to build such a thing. __ John Rishea Craig -- To unsubscribe, e-mail: mailto:[EMAIL PROTECTED] For additional commands, e-mail: mailto:[EMAIL PROTECTED]
