Storing Vector Application Scope - Pressed for time

Question

I'm reading in a file through my application and right now every time a user goes to the page, the file is being read in and parsed etc etc to be formatted for display. Now, I know this can hamper performance dramatically as the users increase, and I want to be able to make this task work optimally.
The file is also being updated through FTP every 15 minutes, and I want to be able to have the correct version read in when a user accesses the page. My first question is whether this is a good way of going about getting and presenting the information?
Secondly, I want to somehow store the Vector of lines from the file globally so that all the users can use it. I want to store the Vector, and a timestamp consisting of the file's last modification date in order to do a check of whether to access the current Vector, or read in the file again and refresh the timestamp all across the application (so the one user to be reading the file during the time that a new file comes in will update it for all other users). What's the best way to go about doing this?
*** Also - If you are familiar with tags, I'd like to know how I can add this functionality to my current tags (one which reads the file, and the other which displays the Vector of lines). I'm not sure how to have the tag just read in session attributes, or just variables that reside on the page.
I really really appreciate your time and help in this matter,
Thank you,
Lior

Answer 1

Caches for all the users. Unfortunately since the code is proprietary, I cannot send you the actual code. But here are the steps to do it:
in web.xml do this:
1.
<servlet>
<servlet-name>ReadfileServlet</servlet-name>
<servlet-class>somepackage.BootstrapServlet</servlet-class>
<init-param>
<param-name>FilePath</param-name>
<param-value>c:\filetoread</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
2.
Create a Global class (say GlobalVariables) which has a member variable (say m_FileContent) and static synchronized set/get methods for the member variable.
3.
In ReadFileServlet's init method,
Read the file specified in FilePath. Then assign it to a servlet member variable (why do you neeed a vector? why not a String?)
Then assign this member variable to the Global class's member variable using the set method (GlobalVariables.setVariable(variable)).
4.
From any jsp use variable = GlobalVariables.getVariable().
Hope this helps.
-Srini