Re: [WebMacro-user

Hi Nikolaos.

This is most disturbing to hear about.

First, there is a known concurrency issue with WM in 2.0 and possibly
in prior releases. If you look at the mail thread dating back for 45
days, you will definitely see it.

My concern is that the webmacro instance, shared, and the context, not
shared, is improperly orchestrated for concurrency. The webmacro
instance is local to WMServlet. You might consider synchronizing access
to this variable as a trial fix in your local calls below. This will
introduce some serialization of web processing but it might help to
verify the solution.

One thing you might consider trying is to use a different cache
handler. A few years ago, I wrote one and it is a part of the distro. I
have never had a problem using this cache handler.

Lane

--- Nikolaos Papadakis <[email protected]> wrote:

From: Nikolaos Papadakis <[email protected]>
Date: Sat, 18 Feb 2006 10:50:33 +0200
To: [email protected]
Subject: [WebMacro-user] [WebMacro-user

Hi all,

I am using webmacro to develop a web-based application.
Things seemed to work fine till yesterday. A customer complained that he
managed to “see” the account of another customer when he logged-in using
his own credentials (he send me a screen shot of the “view”).
By inspecting the log file I found that both users have been logged-in
at the same time (the second customer logged in 3 sec after the first
customer).
The system has more than 1000 customers but this inconvenience happened
for the first time yesterday (?).
It seems that different sessions have been mixed up.
The servlet includes a handle method and uses several other methods
(methods that write and read from a database).
All methods are defined in the same class (that extends WMServlet).
As far as I know servlets must not have instance variables (only local
variables -inside methods- to prevent data corruption and
inconsistencies). However in my servlet I use only one non local
variable (a Logger) and I don't think this is the cause of the problem.
As an attached file I send you a fragment of the before mentioned servlet.
Can instance variables be defined in the case of a servlet that extends
WMServlet? (I mean is it safe? or its not a good practice without
keeping precautions?)
Do you have any idea what can have caused this inconvenience ?
Is the use of methods inside the servlet thread-safe ?

Please help!!!
Nikolaos Papadakis

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