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From Jacob Kjome <>
Subject Re[2]: Servlet channing
Date Thu, 16 Jan 2003 19:57:29 GMT
Hello Nitin,

Not sure what the original email said, but Barracuda's event model
allows for an event hierarchy.  Basically, your events can inherit
from other events.  When the child event is called, the parent event
is the fired and then it goes down the inheritance chain until it
reaches the original child event.  You can, at any point, handle the
event and stop the cascade, or you can run various code for the parent
events and let the child even finally do its thing.

It is really quite nice.  You can build security around this as well.  For
instance, if you have "SomeEvent" inheriting from "SecureEvent"
(which, itself inherits from "RequestEvent", when
"SomeEvent" is called, "SecurEvent" get to check, first, whether the
user has access to "SomeEvent".  If not, the event can be flagged as
"handled" and event processing can be forwarded off to some other
"ErrorEvent" which might extend from "RenderEvent".

That's just a simple example.  Check out Barracuda at:

I suggest grabbing the latest CVS.  It is very stable and things have
changed moderately significantly since the last release (1.1.1).  A
new release should happen in not too long.


Thursday, January 16, 2003, 1:28:56 PM, you wrote:

RH> Some people would recommend to you that you look into struts, which is an web-application

RH> Servlet chaining in it's most simple way is a servlet that forwards the request to
another servlet. This can be achived by using the RequestDispatcher, be aware that using the
RH> may slow your application down a little bit because (I've heard) it's not fully optimized
in tomcat. 

RH> I wrote servlet-chaining mechanism, it was not hard to do, so I recommend that if this
is something you really think you need, you should write your own servlet chianing API. 

RH> -reynir

>> -----Original Message-----
>> From: Craig R. McClanahan [] 
>> Sent: 16. janĂșar 2003 18:29
>> To: Tomcat Users List
>> Subject: Re: Servlet channing
>> On Thu, 16 Jan 2003, nitin mandolkar wrote:
>> > Date: Thu, 16 Jan 2003 05:45:12 +0000 (GMT)
>> > From: nitin mandolkar <>
>> > Reply-To: Tomcat Users List <>
>> > To:
>> > Subject: Servlet channing
>> >
>> >
>> > How to achive servlet channing with tomcat
>> Servlet chaining (in the manner you describe) is not 
>> supported by the servlet spec.  However, you can accomplish 
>> something very similar using filters instead (Tomcat 4.x or later).
>> Craig
>> --
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