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lib/AnyEvent/Blackboard.pm  view on Meta::CPAN

package AnyEvent::Blackboard;

=head1 NAME

AnyEvent::Blackboard - An extension of Async::Blackboard which uses AnyEvent
for timeouts.

=head1 SYNOPSIS

  my $blackboard = AnyEvent::Blackboard->new();

  $blackboard->watch([qw( foo bar )], [ $object, "found_foobar" ]);
  $blackboard->watch(foo => [ $object, "found_foo" ]);

  # After 250ms, provide ``undef'' for ``foo''
  $blackboard->timeout(foo => 0.25);

=head1 RATIONALE

Async::Blackboard makes a fantastic synchronization component -- however, it
does have the possible condition of allowing control to be abandoned due to a
lack value.  This subclass adds the functionality of timeouts on keys to ensure
this doesn't happen.

=cut

use strict;
use warnings FATAL => "all";

use AnyEvent;
use parent qw( Async::Blackboard );
use Carp qw( croak confess );

our $VERSION = "0.4.10";

=head1 ATTRIBUTES

=over 4

=cut

=item default_timeout -> Num

Default timeout in (optionally fractional) seconds.

=cut

=item condvar -> AnyEvent::CondVar

A conditional variable to track dispatches. (optional)

When supplied, each dispatch group will be wrapped in calls to ``begin'' and
``end'' on condvar instance.

=cut

sub new {
    my ($class, @arguments) = @_;

    if (@arguments % 2) {
        croak "AnyEvent::Blackboard->new() requires a balanced list";
    }

    my %options = @arguments;

    my $self = $class->SUPER::new();

    @$self{qw( -default_timeout -condvar )} =
        @options{qw( default_timeout condvar )};

    $self->{-condvar} //= AnyEvent->condvar;

    return $self;
}

=back

=cut

=back