| Moose documentation | Contained in the Moose distribution. |
InstanceCountingClass - An example metaclass which counts instances
package Foo;
use metaclass 'InstanceCountingClass';
sub new {
my $class = shift;
$class->meta->new_object(@_);
}
# ... meanwhile, somewhere in the code
my $foo = Foo->new();
print Foo->meta->get_count(); # prints 1
my $foo2 = Foo->new();
print Foo->meta->get_count(); # prints 2
# ... etc etc etc
This is a classic example of a metaclass which keeps a count of each instance which is created.
Stevan Little <stevan@iinteractive.com>
Yuval Kogman <nothingmuch@woobling.com>
Copyright 2006-2008 by Infinity Interactive, Inc.
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
| Moose documentation | Contained in the Moose distribution. |
package # hide the package from PAUSE InstanceCountingClass; use strict; use warnings; our $VERSION = '0.03'; use base 'Class::MOP::Class'; InstanceCountingClass->meta->add_attribute('count' => ( reader => 'get_count', default => 0 )); InstanceCountingClass->meta->add_before_method_modifier('_construct_instance' => sub { my ($class) = @_; $class->{'count'}++; }); 1; __END__