package Bread::Board::LifeCycle::Singleton::WithParameters;
our $AUTHORITY = 'cpan:STEVAN';
# ABSTRACT: singleton lifecycle role for a parameterized service
$Bread::Board::LifeCycle::Singleton::WithParameters::VERSION = '0.35';
use Moose::Role;
with 'Bread::Board::LifeCycle';
has 'instances' => (
traits => [ 'Hash', 'NoClone' ],
is => 'rw',
isa => 'HashRef',
lazy => 1,
default => sub { +{} },
clearer => 'flush_instances',
handles => {
'has_instance_at_key' => 'exists',
'get_instance_at_key' => 'get',
'set_instance_at_key' => 'set',
}
);
around 'get' => sub {
my $next = shift;
my $self = shift;
my $key = $self->generate_instance_key(@_);
# return it if we got it ...
return $self->get_instance_at_key($key)
if $self->has_instance_at_key($key);
# otherwise fetch it ...
my $instance = $self->$next(@_);
# if we get a copy, and our copy
# has not already been set ...
$self->set_instance_at_key($key => $instance)
unless $self->has_instance_at_key($key);
# return whatever we have ...
return $self->get_instance_at_key($key);
};
sub generate_instance_key {
my ($self, @args) = @_;
return "$self" unless @args;
return join "|" => sort map { "$_" } @args
}
no Moose::Role; 1;
__END__
=pod
=encoding UTF-8
=head1 NAME
Bread::Board::LifeCycle::Singleton::WithParameters - singleton lifecycle role for a parameterized service
=head1 VERSION
version 0.35
=head1 DESCRIPTION
Sub-role of L<Bread::Board::LifeCycle>, this role defines the
"singleton" lifecycle for a parameterized service. The C<get> method
will only do its work the first time it is invoked for each set of
parameters; subsequent invocations with the same parameters will
return the same object.
=head1 ATTRIBUTES
=head2 C<instances>
Hashref mapping keys to objects, used to cache the results of L</get>
=head1 METHODS
=head2 C<get>
Generates a key using L</generate_instance_key> (passing it all the
arguments); if the L</instances> attribute does not hold an object for
that key, it will build it (by calling the underlying C<get> method)
and store it in L</instances>. The object (either retrieved from
L</instances> or freshly built) will be returned.
=head2 C<generate_instance_key>
Generates a (hopefully) unique key from the given arguments (usually,
whatever was passed to L</get>). The current implementation
stringifies all arguments, so different references to identical values
will be considered different.
=head1 AUTHOR
Stevan Little <stevan@iinteractive.com>
=head1 BUGS
Please report any bugs or feature requests on the bugtracker website
https://github.com/stevan/BreadBoard/issues
When submitting a bug or request, please include a test-file or a
patch to an existing test-file that illustrates the bug or desired
feature.
=head1 COPYRIGHT AND LICENSE
This software is copyright (c) 2017, 2016, 2015, 2014, 2013, 2011, 2009 by Infinity Interactive.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
=cut