Cache::Memcached::Queue(3)

NAME
Cache::memcached::Queue - Create queues and save them on memcached!

VERSION
Version 0.0.2 alpha

DESCRIPTION
This works by taking advantage of Memcached infrastructure. In other words, the 'keys' will be strings that are names of indexes for some basic values that are sufficient to represent a queue structure. This basic values are: first, last, size and max_enq.

In order to have multiples queues in the same Memcached server, a prefix are added to every index on keys of Memcached. So, every key in memcached have the following struct on his name: <PREFIX>_<ID>_<INDEX_NUMBER OR NAME>

PREFIX - This is defined by the 'id_prefix' attribute. The default value is 'CMQID_'
ID - This is defined by the 'id' attribute.
INDEX_NUMBER OR NAME - If some data is a item in the queue, so this must be a sequential number, for example: 'CMQID_1_1' This can be the first element from queue with id 1. If some data in the queue is a pointer, this pointer must be named, for example: 'CMQID_1_first' This is the pointer to the first element in queue.

SYNOPSIS
This module implements a simple scheme of a Queue.

    use Cache::memcached::Queue;

    my $q = Cache::memcached::Queue->new( name => 'foo', #this is mandatory
                                                max_enq => 10,
                                                config_file => 'path_to_config/configfile.cfg',
                                                id => 1,
                                        )->init;

    $q->load();#load data from Memcached

    $q->enq('duke'); #enqueue 'duke'.

    $q->enq('nuken'); #enqueue 'nuke' and this never expires on memcached

    $q->show; #show all items from queue. In this case: 'duke'(first element) and 'nuken'(last element).

    $q->deq; #deqeue 'duke'.

    $q->show; #show all items from queue. In this case: 'nuke'(first and last element from queue).

or

    $q->enq({ qid => 1, #queue id = 1
                value => 'Duke'},);
    $q->enq({ qid => 2, #queue id = 2
                value => 'Nuken'},);

    $q->deq({qid => 1}); #brings 'Duke'

    $q->deq({qid => 1}); #brings 'queue empty'

    $q->deq({qid => 2}); #brings 'Nuken'

  init()
Initialize object attributes and check attributes problems. If all is ok, returns the reference to object. Otherwise returns undef and trows an exception

  load()
Try to load the queue pointers from Memcached. If works, will return true. Otherwise will return false.

  enq($parameters)
Try to make a 'enqueue' operation. That means tha 'last' index pointer will be readjusted to the next index. So the value can be recorded on Memcached.

The parameters are validated, and the valid parameters are:

value - A value that presupposes that you want to save
serialize - If you need the value to be serialized, you must set serialized to true(1). NOT IMPLEMENTED YET.

Example: $enq({value => 'some_value'});

Example2: $enq({value => $some_object_or_structure,
                serialize => 1, });

If this work, the method will return true. Otherwise, will return false.

  deq()
Try to make a 'dequeue' operation on Queue. That means the first value of queue will be removed from queue, and the first index pointer from queue will be moved to the next index. If works, returns the 'dequeued' value, otherwise returns undef.

  show()
Try to show the content of queue(the data). This is made finding the 'first' and 'last' pointers, extracting the sequential index, and interate the queue with this indexes, making a 'get' operation from Memcached. If the value exists, it will be showed. If not, a exception will be thrown .

  cleanup()
Dequeue everything!

  save($parameters)
Try to save queue pointers on Memcached. The parameters came on arrayref, when each position of arrayref is a name of attribute that must be saved. This parameters are validated and then saved on memcached.

That makes the enqueuing process faster than save all parameters everytime, because the input operations on Memcached are reduced.

Ex: $q->save(['name','first']);

The valid parameters are:

name - Is the name of Queue;
first - Is the first index of the key. Not the value, but the name of index;
last - As the same way, this is the last index of the queue.

If everything work well the method returns true. Otherwise returns false.

AUTHOR
Andre Garcia Carneiro, "<bang at cpan.org>"

BUGS
Please report any bugs or feature requests to "bug-cache-memcached-queue at rt.cpan.org", or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Cache-memcached-Queue <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Cache-memcached-Queue>. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT
You can find documentation for this module with the perldoc command.

    perldoc Cache::memcached::Queue

You can also look for information at:

•   RT: CPAN's request tracker

    http://rt.cpan.org/NoAuth/Bugs.html?Dist=Cache-memcached-Queue <http://rt.cpan.org/NoAuth/Bugs.html?Dist=Cache-memcached-Queue>

•   AnnoCPAN: Annotated CPAN documentation

    http://annocpan.org/dist/Cache-memcached-Queue <http://annocpan.org/dist/Cache-memcached-Queue>

•   CPAN Ratings

    http://cpanratings.perl.org/d/Cache-memcached-Queue <http://cpanratings.perl.org/d/Cache-memcached-Queue>

•   Search CPAN

    http://search.cpan.org/dist/Cache-memcached-Queue/ <http://search.cpan.org/dist/Cache-memcached-Queue/>

ACKNOWLEDGEMENTS

LICENSE AND COPYRIGHT
Copyright 2011 Andre Garcia Carneiro.

This program is free software; you can redistribute it and/or modify it under the terms of either: the GNU General Public License as published by the Free Software Foundation; or the Artistic License.

See http://dev.perl.org/licenses/ for more information.