NAME¶
Aspect::Library::Singleton - A singleton aspect
SYNOPSIS¶
use Aspect;
use Aspect::Singleton;
aspect Singleton => 'Foo::new';
my $f1 = Foo->new;
my $f2 = Foo->new;
# Both $f1 and $f2 refer to the same object
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
<
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 Gruenauer <marcel@cpan.org>
Ran Eilam <eilara@cpan.org>
COPYRIGHT¶
Copyright 2001 by Marcel Gruenauer
Some parts copyright 2009 - 2013 Adam Kennedy.
This library is free software; you can redistribute it and/or modify it under
the same terms as Perl itself.