
=head1 NAME

Mail::Box::Locker::NFS - lock a folder with a separate file, NFS-safe


=head1 INHERITANCE

 Mail::Box::Locker::NFS
   is a Mail::Box::Locker
   is a Mail::Reporter


=head1 SYNOPSIS

 See Mail::Box::Locker


=head1 DESCRIPTION

Like the C<::DotLock> locker, but then in an NFS-safe fashion.  Over NFS,
the creation of a file is not atomic.  The C<::DotLock> locker depends
on an atomic C<open> system call, hence in not usable to lock a folder
which accessed over NFS.  The C<::NFS>
locker is therefore more complicated (so therefore slower), but will work
for NFS --and for local disks as well.



=head1 METHODS


=head2 Constructors


Mail::Box::Locker::NFS-E<gt>B<new>(OPTIONS)

=over 4

 Option   Defined in       Default      
 expires  L<Mail::Box::Locker>  1 hour       
 file     L<Mail::Box::Locker>  undef        
 folder   L<Mail::Box::Locker>  <required>   
 log      L<Mail::Reporter>  C<'WARNINGS'>
 method   L<Mail::Box::Locker>  C<'NFS'>     
 timeout  L<Mail::Box::Locker>  10 seconds   
 trace    L<Mail::Reporter>  C<'WARNINGS'>

. expires SECONDS

. file FILENAME

. folder FOLDER

. log LEVEL

. method METHOD | CLASS

. timeout SECONDS|'NOTIMEOUT'

. trace LEVEL

=back

=head2 The Locker


$obj-E<gt>B<filename>([FILENAME])

=over 4

See L<Mail::Box::Locker/"The Locker">

=back

$obj-E<gt>B<folder>

=over 4

See L<Mail::Box::Locker/"The Locker">

=back

$obj-E<gt>B<name>

=over 4

See L<Mail::Box::Locker/"The Locker">

=back

=head2 Locking


$obj-E<gt>B<hasLock>

=over 4

See L<Mail::Box::Locker/"Locking">

=back

$obj-E<gt>B<isLocked>

=over 4

See L<Mail::Box::Locker/"Locking">

=back

$obj-E<gt>B<lock>

=over 4

=back

$obj-E<gt>B<unlock>

=over 4

See L<Mail::Box::Locker/"Locking">

=back

=head2 Error handling


$obj-E<gt>B<AUTOLOAD>

=over 4

See L<Mail::Reporter/"Error handling">

=back

$obj-E<gt>B<defaultTrace>([LEVEL, [LEVEL])

Mail::Box::Locker::NFS-E<gt>B<defaultTrace>([LEVEL, [LEVEL])

=over 4

See L<Mail::Reporter/"Error handling">

=back

$obj-E<gt>B<errors>

=over 4

See L<Mail::Reporter/"Error handling">

=back

$obj-E<gt>B<log>([LEVEL [,STRINGS]])

Mail::Box::Locker::NFS-E<gt>B<log>([LEVEL [,STRINGS]])

=over 4

See L<Mail::Reporter/"Error handling">

=back

$obj-E<gt>B<logPriority>(LEVEL)

Mail::Box::Locker::NFS-E<gt>B<logPriority>(LEVEL)

=over 4

See L<Mail::Reporter/"Error handling">

=back

$obj-E<gt>B<logSettings>

=over 4

See L<Mail::Reporter/"Error handling">

=back

$obj-E<gt>B<notImplemented>

=over 4

See L<Mail::Reporter/"Error handling">

=back

$obj-E<gt>B<report>([LEVEL])

=over 4

See L<Mail::Reporter/"Error handling">

=back

$obj-E<gt>B<reportAll>([LEVEL])

=over 4

See L<Mail::Reporter/"Error handling">

=back

$obj-E<gt>B<trace>([LEVEL])

=over 4

See L<Mail::Reporter/"Error handling">

=back

$obj-E<gt>B<warnings>

=over 4

See L<Mail::Reporter/"Error handling">

=back

=head2 Cleanup


$obj-E<gt>B<DESTROY>

=over 4

See L<Mail::Box::Locker/"Cleanup">

=back

$obj-E<gt>B<inGlobalDestruction>

=over 4

See L<Mail::Reporter/"Cleanup">

=back



=head1 DIAGNOSTICS

I<Error:> Package $package does not implement $method.

Fatal error: the specific package (or one of its superclasses) does not
implement this method where it should. This message means that some other
related classes do implement this method however the class at hand does
not.  Probably you should investigate this and probably inform the author
of the package.

I<Warning:> Removed expired lockfile $filename.

A lock file was found which was older than the expiration period as
specified with L<new(timeout)|Mail::Box::Locker/"METHODS">.  The lock file was succesfully
removed.

I<Error:> Unable to remove expired lockfile $lockfile: $!

A lock file was found which was older than the expiration period as
specified with the L<new(timeout)|Mail::Box::Locker/"METHODS"> option.  It is impossible to remove that
lock file, so we need to wait until it vanishes by some external cause.






=head1 REFERENCES

See the Mail::Box website at L<http://perl.overmeer.net/mailbox/> for more details.

=head1 COPYRIGHTS

Module version 2.042.
Written by Mark Overmeer (mark@overmeer.net).  See the ChangeLog for
other contributors.

Copyright (c) 2001-2003 by the author(s). All rights reserved.
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.


