Aspect::Library::Singleton.3pm

Langue: en

Version: 2010-05-27 (ubuntu - 24/10/10)

Section: 3 (Bibliothèques de fonctions)

Sommaire

NAME

Aspect::Library::Singleton - A singleton aspect

SYNOPSIS

   use Aspect::Singleton;
 
   aspect Singleton => 'Foo::new';
 
   my $f1 = Foo->new;
   my $f2 = Foo->new;
 
   # now $f1 and $f2 refer to the same object

SUPER

Aspect::Modular

DESCRIPTION

A reusable aspect that forces singleton behavior on a constructor. The constructor is defined by a pointcut spec: a string. regexp, or code ref.

It is slightly different from "Class::Singleton" (<http://search.cpan.org/~abw/Class-Singleton/Singleton.pm>):

•
No specific name requirement on the constructor for the external interface, or for the implementation ("Class::Singleton" requires clients use "instance()", and that subclasses override "_new_instance()"). With aspects, you can change the cardinality of your objects without changing the clients, or the objects themselves.
•
No need to inherit from anything- use pointcuts to specify the constructors you want to memoize. Instead of pulling singleton behavior from a base class, you are pushing it in, using the aspect.
•
No package variable or method is added to the callers namespace

Note that this is just a special case of memoizing.

AUTHORS

Adam Kennedy <adamk@cpan.org>

Marcel Gru.nauer <marcel@cpan.org>

Ran Eilam <eilara@cpan.org>

Copyright 2001 by Marcel Gru.nauer

Some parts copyright 2009 - 2010 Adam Kennedy.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.