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GWILLIAMS / Attean-0.035 / lib / Attean / QuadModel.pm 

            

              
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use v5.14;
use warnings;
=head1 NAME
Attean::QuadModel - RDF model backed by a quad-store
=head1 VERSION
This document describes Attean::QuadModel version 0.035
=head1 SYNOPSIS
  use v5.14;
  use Attean;
  my $model = Attean::QuadModel->new( store => $store );
=head1 DESCRIPTION
The Attean::QuadModel class represents a model that is backed by a single
L<Attean::API::QuadStore|Attean::API::Store> object.
It conforms to the L<Attean::API::Model> role.
The Attean::QuadModel constructor requires one named argument:
=over 4
=item store
A L<Attean::API::QuadStore|Attean::API::Store> object representing the backing
quad-store.
=back
=head1 METHODS
=over 4
=cut
package Attean::QuadModel 0.035 {
        use Moo;
        use Scalar::Util qw(reftype);
        use namespace::clean;
        has 'store'     => (
                is => 'ro',
                does => 'Attean::API::QuadStore',
                required => 1,
                handles => [qw(size count_quads count_quads_estimate get_graphs holds)],
        );
         
=item C<< get_quads ( $subject, $predicate, $object, $graph ) >>
Returns an L<Attean::API::Iterator> for quads in the model that match the
supplied C<< $subject >>, C<< $predicate >>, C<< $object >>, and C<< $graph >>.
Any of these terms may be undefined or a L<Attean::API::Variable> object, in
which case that term will be considered as a wildcard for the purposes of
matching.
The returned iterator conforms to both L<Attean::API::Iterator> and
L<Attean::API::QuadIterator>.
=cut
        sub get_quads {
                my $self        = shift;
                my @nodes       = @_[0..3];
                foreach my $i (0..3) {
                        my $t   = $nodes[$i];
                        if (not(ref($t)) or reftype($t) ne 'ARRAY') {
                                $nodes[$i]      = [$t];
                        }
                }
                 
                my @iters;
                foreach my $s (@{ $nodes[0] }) {
                        foreach my $p (@{ $nodes[1] }) {
                                foreach my $o (@{ $nodes[2] }) {
                                        foreach my $g (@{ $nodes[3] }) {
                                                push(@iters, $self->store->get_quads($s, $p, $o, $g));
                                        }
                                }
                        }
                }
                 
                if (scalar(@iters) == 0) {
                        return Attean::ListIterator->new(values => [], item_type => 'Attean::API::Quad');
                } elsif (scalar(@iters) == 1) {
                        return shift(@iters);
                } else {
                        return Attean::IteratorSequence->new( iterators => \@iters, item_type => $iters[0]->item_type );
                }
        }
         
=item C<< plans_for_algebra( $algebra, $model, $active_graphs, $default_graphs ) >>
Delegates to the underlying store if the store consumes Attean::API::CostPlanner.
=cut
        sub plans_for_algebra {
                my $self        = shift;
                if ($self->store->does('Attean::API::CostPlanner')) {
                        return $self->store->plans_for_algebra(@_);
                }
                return;
        }
         
=item C<< cost_for_plan( $plan ) >>
Delegates to the underlying store if the store consumes Attean::API::CostPlanner.
=cut
        sub cost_for_plan {
                my $self        = shift;
                if ($self->store->does('Attean::API::CostPlanner')) {
                        return $self->store->cost_for_plan(@_);
                }
                return;
        }
         
        with 'Attean::API::Model';
        with 'Attean::API::CostPlanner';
}
package Attean::MutableQuadModel 0.035 {
        use Moo;
        extends 'Attean::QuadModel';
         
        has 'store'     => (
                is => 'ro',
                does => 'Attean::API::MutableQuadStore',
                required => 1,
                handles => [qw(size count_quads count_quads_estimate add_quad remove_quad get_graphs create_graph drop_graph clear_graph add_iter)],
        );
        with 'Attean::API::MutableModel';
}
1;
__END__
=back
=head1 BUGS
Please report any bugs or feature requests to through the GitHub web interface
at L<https://github.com/kasei/attean/issues>.
=head1 SEE ALSO
=head1 AUTHOR
Gregory Todd Williams  C<< <gwilliams@cpan.org> >>
=head1 COPYRIGHT
Copyright (c) 2014--2022 Gregory Todd Williams.
This program is free software; you can redistribute it and/or modify it under
the same terms as Perl itself.
=cut