File Coverage

blib/lib/State/Machine.pm

Criterion	Covered	Total	%
statement	36	43	83.7
branch	3	8	37.5
condition	2	6	33.3
subroutine	10	12	83.3
pod	3	3	100.0
total	54	72	75.0

# ABSTRACT: Simple State Machine Implementation
package State::Machine;

use Bubblegum::Class;
use Function::Parameters;
use State::Machine::Failure::Transition::Execution;
use State::Machine::Failure::Transition::Missing;
use State::Machine::Failure::Transition::Unknown;
use Try::Tiny;

use Bubblegum::Constraints -typesof;

our $VERSION = '0.07'; # VERSION

has 'state' => (
    is       => 'rw',
    isa      => typeof_object,
    required => 1
);

has 'topic' => (
    is       => 'ro',
    isa      => typeof_string,
    required => 1
);

method apply {
    my $state = $self->state;
    my $next  = $self->next;

    # cannot transition
    State::Machine::Failure::Transition::Missing->throw
        unless $next->isa_string;

    # find transition
    if (my $trans = $state->transitions->get($next)) {
        try {
            # attempt transition
            $self->state($trans->execute($state, @_));
        }
        catch {
            # transition execution failure
            State::Machine::Failure::Transition::Execution->throw(
                captured          => $_,
                transition_name   => $next,
                transition_object => $trans,
            );
        }
    }
    else {
        # transition unknown
        State::Machine::Failure::Transition::Unknown->throw(
            transition_name => $next
        );
    }

    return $self->state;
};

method next {
    my $state = $self->state;
    my $next  = shift // $state->next;

    if ($state && !$next) {
        # deduce transition unless defined
        if ($state->transitions->keys->count == 1) {
            $next = $state->transitions->keys->get(0);
        }
    }

    return $next;
}

method status {
    return $self->state->name;
}

1;

__END__