🚀 go-pugleaf

Terry Swiers wrote:

> I'm just starting to play around with JBuilder and have one question in
> particular that I can't seem to find the answer to.  Is there any type of
> file locking capabilities in Java?  In short, I need to be able to have one
> user open a file exclusively on a internet server for a few seconds and then
> release it for the next person.  Is this possible?

Part 1: In any language, the process of locking files is pretty much the same.
You either (1) open a file handle for append access or (2) maintain your own
internal locking list.  I don't recall all the specific file I/O classes or
methods so I can't direct you to a specific piece of code.  However, I'm sure if
you browsed the JDK documentation in the area of java.io.*, you'll find
something that works.

Part 2: But if you are attempting to lock a file from a downloaded applet, then
no dice.  This is one of the many restricted operations applets cannot perform
without many tricks.  You will need to have some sort of custom application
(Java or otherwise) running on the web server to do the file locking for the
applet.  Of course, you will have to develop some method of communicating with
this server application -- the choices you have are CGI, sockets, RMI or CORBA.