Weird Redirection Problem

Question

I've written a custom tag that manages its own state in the user's session. It is an interactive tag; if the user clicks on a tag element then a request is made to the same page with some special request parameters. These parameters are read by the tag handler and are used to update the tag's state in the session. The tag component then reads its state from the session and renders itself to pageContext.getOut( ).
This works great with one user. However, when there are multiple users I will occasionally be redirected to the JSP the other user is viewing at the time. I don't know how this could be happening other than the Request or PageContext objects being reused for multiple users. The tag builds the postback URL from pageContext.getRequestURI( ), so the only way the URI could be wrong is if pageContext was the one from the other user.
This problem has been duplicated in Tomcat 4.1 and Netscape Enterprise Server 6.1.
Has anyone else seen this happen? Any suggestions on troubleshooting it?
Thanks,
- Jesse

Answer 1

Different client PCs hitting the same webserver. I've tried it where both PCs use the same login credentials and where both PCs use different login credentials with the same results. Timing seems to be a factor; it happens pretty infrequently unless we're both clicking like mad men.
Another note: in my tests the other person has always been accessing a different portion of the site that does not use these custom tags. The custom tags are used on one and only one page (that I test) and sometimes I get redirected to other portions of the site (where the other user happens to be at the time).
It's really strange...it's like the same PageContext instance is being used and is simply refreshed with new values every time a new request comes in. I say that because the custom tag components (which are created by the tag handler and do not themselves extend TagSupport) store a reference to the PageContext in the tag handler class and use that to generate the links. Since I'm not updating this value (the components reside in the session) one can only assume that the same PageContext instance is being used elsewhere to service other requests.
That might have been confusing...so let me clarify with this. TreeTag is the tag handler that extends BodyTagSupport. Tree is a component class that I use to store state in the session. TreeTag has a field called "pageContext" that (supposedly) contains the PageContext for the request. If a Tree doesn't exist in the session, one is created and given a reference to the value of pageContext. After that, the Tree in the session is used, so it should be the same PageContext instance.
Hope I didn't muddle that too much...
- Jesse