public class FileLock
extends Object
Sometimes it is necessary to lock a file at the disk level. Since there is no
native Java way of locking a file, we have to implement our own.
Unfortunately, it appears as though we can only assume that rename is atomic.
We base the locking on this then: rename the lock file and update it with the
lock owners. How it works: for every file we want to lock we create an _lock
file. This file contains information about who is locking the file, and in
what mode. (Single writer, multiple readers.) To guarantee atomicity of
update, we move (rename) the actual file each time we want to lock it and
update the lock file. When this is done, we move (rename) it back. Almost
like a two-phase commit protocol! Currently we don't support re-entrant
locking.
- Since:
- JTS 1.0.
- Version:
- $Id: FileLock.java 2342 2006-03-30 13:06:17Z $
- Author:
- Mark Little (mark@arjuna.com)