At an extremely simple level, I would create a lockfile (like mentioned before, similar to OpenOffice and Microsoft Office) but I would have details in it containing the name of the machine and user, and process details, and then look to see if that machine/user/process still exists when I want to lock the file. If it can be found then the file is locked, if not then the file is no longer locked. Obviously, removing the file at the end of need will make the lock check easier for the next process.

I can't remember exactly how to check for the existence of a process over the network, but the idea should cover everything you need. I think.


-----Original Message-----
From: JAVA400-L [mailto:java400-l-bounces@xxxxxxxxxxxx] On Behalf Of David Gibbs
Sent: 07 November 2014 14:48
To: Java Programming on and around the IBM i
Subject: Re: Create an exclusive lock on an IFS file?

On 11/7/2014 7:48 AM, Ron Byrd wrote:
Have you looked into the "Check Out" and "Check In" processes that are
available from within the IBM I Navigator. I do not know if this
process is available from within Java or not.

If I understand the CHKIN & CHKOUT commands correctly, this would create a static lock that would persist after the connection from the java app was dropped. I don't want this.

I want to create a system level lock to prevent the same application, running on two workstations, from performing the same function at the same time.


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