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Tie::Array::QueueExpire - Introduction
Tie::Array::QueueExpire - Tie an ARRAY over a TokyCabinet Btree DB ( see http://tokyocabinet.sourceforge.net )
Revision: 1.01
SYNOPSIS
use Tie::Array::QueueExpire;
my $t = tie( my @myarray, "Tie::Array::QueueExpire", '/tmp/db_test.bdb' );
push @myarray, int rand 1000;
# normal ARRAY function
my $data = shift @myarray;
my $data = pop @myarray;
print "this elem exists\n" if (exists( $myarray[6]));
print "size = ". scalar( @myarray )."\n";
# using the PUSH with an extra parameter to put the new element in futur
# also return the key of the inserted value
for ( 1 .. 10 )
{
say "t=".time.' '. int (($t->PUSH( $_ . ' ' . time, 10 ))/1000);
sleep 1;
}
sleep 10;
# Get the expired elements ( 7 seconds before now )
my $ex = $t->EXPIRE( 7 );
# Get the expired elements
my @EXP = @{$t->EXPIRE($exp)};
# Get and delete the expired elements ( 20 seconds before now )
$ex = $t->EXPIRE(20,1);
my @EXP = @{$t->EXPIRE($exp,1)};
# fetch element
# in scalar context return the value
# in array context return in first element the key and in second, the value
my $a =$t->FETCH(6);
my @b = $t->FETCH(6);
# the normal array fetch is always in scalar mode
my @c=$myarray[6];
say Dumper( $a );
say Dumper( \@b );
say Dumper( \@c );
DESCRIPTION
Tie an ARRAY over a TokyCabinet Btree DB and allow to get or deleted expired data;
This module require Time::HiRes, TokyoCabinet (database and perl module.)
The insertion is ms unique ( 0.001 seconds )
The normal ARRAY function present are
push
pop
shift
exits
scalar
clear
unshift (but put data 1 second before the first entry)
The following function is not completely iplemented.
splice
The following function are not implemented.
extend
store
STORESIZE
The following function are specific of this module.
LAST
FIRST
EXPIRE
OPTIMIZE
PUSH
FETCH
Basic ARRAY functions
* *
tie
Tie an array over a TokyoCabinet DB
my $t = tie( my @myarray, "Tie::Array::QueueExpire", '/tmp/db_test.bdb' );
The fist parameter if the TokyoCabinet file used (or created)
Four optional parameter are allowed
In place two, a flag to serialize the data in the DB
In place three, an octal MASK allow to set the permission of the DB created
The default permission is 0600 (-rw-------)
In place four a parameter to delete the DB file if present and corrupted
The default value is 0 (don't delete the file)
In place five a parameter to exit on error when opening the DB file
The default value is 0 (don't exit, only report error)
FETCH
Retrieve a specific key from the array
my $data = $myarray[6];
or
my $data = $t->FETCH(6);
or
my @data = $t->FETCH(6);
where
$data[0] = insertion key
and
$data[1] = value
FETCHSIZE
Get the size of the array
my $data = scalar(@myarray);
PUSH
Add an element at the end of the array
push @myarray , 45646;
or
$t->PUSH( 45646 );
it is also possible to add an elemnt with a offset expiration
$t->PUSH( 45646 , 10 );
add element in the array to be expired in 10 seconds
if the offset is negative, add the expiration in past
EXISTS
Test if en element in the array exist
print "element exists\n" if (exits $myarray[5]);
return the insertion key
POP
Extract the latest element from the array (the youngest)
my $data = pop @myarray;
or
my $data = $t->POP();
or
my @data = $t->POP();
where
$data[0] = insertion key
and
$data[1] = value
SHIFT
Extract the first element from the array (the oldest)
my $data = shift @myarray;
or
my $data = $t->SHIFT();
or
my @data = $t->SHIFT();
where
$data[0] = insertion key
and
$data[1] = value
UNSHIFT
Add an element in the front of the array
unshift @myarray , 45646;
UNSHIFT data 1 mili-second before the first item
CLEAR
Delete all element in the array
$t->CLEAR;
DESTROY
Normal destructor call when untied the array
Normaly never called by user
Specific functions from this module
* *
SPLICE
SPLICE don't allow a list replacement
because the insert order is made by time.
my @tmp = splice @myarray, 5 ,3;
LAST
Get the latest element in the array (oldest)
my $data = $t->LAST;
or
my @data = $t->LAST;
where
$data[0] = insertion key
and
$data[1] = value
FIRST
Get the first element in the array (youngest)
my $data =$t->FIRST;
or
my @data = $t->FIRST;
where
$data[0] = insertion key
and
$data[1] = value
EXPIRE
Get the elements expired in the array.
my @ALL = $t->EXPIRE( 1207840028) ;
return a refernce to an array with all the expired value.
If a second parameter is provided and not null, the data are also deleted from the array.
my @ALL = $t->EXPIRE( 1207840028 , 1 ) ;
return a refernce to an array with all the expired value.
OPTIMIZE
Function to compact the DB (after a lot of delete )
$t->OPTIMIZE;
Functions not Implemented
* *
EXTEND
Not implemented because not signifiant for a expiration queue
STORE
Not implemented because not signifiant for a expiration queue
STORESIZE
Not implemented because not signifiant for a expiration queue
AUTHOR
Fabrice Dulaunoy <fabrice_at_dulaunoy_dot_com>
SEE ALSO
- Data::Queue::Persistent from Mischa Spiegelmock, <mspiegelmock_at_gmail_dot_com>
- TokyoCabinet from Mikio Hirabayashi <mikio_at_users_dot_sourceforge_dot_net>
TODO
- make test
- implementation of EXTEND to allow clear of array with @myarray = ();
- implementation of STORESIZE to allow clear of array with $#myarray = -1;
LICENSE
Under the GNU GPL2
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public
License as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the
Free Software Foundation, Inc., 59 Temple Place,
Suite 330, Boston, MA 02111-1307 USA
Tie::Array::QueueExpire Copyright (C) 2004 2005 2006 2007 2008 2009 2010 DULAUNOY Fabrice
Tie::Array::QueueExpire comes with ABSOLUTELY NO WARRANTY;
for details See: L<http://www.gnu.org/licenses/gpl.html>
This is free software, and you are welcome to redistribute
it under certain conditions;