/usr/share/perl5/RDF/Query/Algebra/Triple.pm is in librdf-query-perl 2.918-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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# -----------------------------------------------------------------------------
=head1 NAME
RDF::Query::Algebra::Triple - Algebra class for Triple patterns
=head1 VERSION
This document describes RDF::Query::Algebra::Triple version 2.918.
=cut
package RDF::Query::Algebra::Triple;
use strict;
use warnings;
no warnings 'redefine';
use base qw(RDF::Query::Algebra RDF::Trine::Statement);
use Data::Dumper;
use Log::Log4perl;
use Scalar::Util qw(refaddr);
use Carp qw(carp croak confess);
use Scalar::Util qw(blessed reftype refaddr);
use Time::HiRes qw(gettimeofday tv_interval);
use RDF::Trine::Iterator qw(smap sgrep swatch);
######################################################################
our ($VERSION);
my %TRIPLE_LABELS;
my @node_methods = qw(subject predicate object);
BEGIN {
$VERSION = '2.918';
}
######################################################################
=head1 METHODS
Beyond the methods documented below, this class inherits methods from the
L<RDF::Query::Algebra> class.
=over 4
=cut
=item C<new ( $s, $p, $o )>
Returns a new Triple structure.
=cut
sub new {
my $class = shift;
my @nodes = @_;
foreach my $i (0 .. 2) {
unless (defined($nodes[ $i ])) {
$nodes[ $i ] = RDF::Query::Node::Variable->new($node_methods[ $i ]);
}
if (blessed($nodes[ $i ]) and not($nodes[ $i ]->isa('RDF::Query::Node'))) {
if ($nodes[ $i ]->isa('RDF::Trine::Node')) {
$nodes[ $i ] = RDF::Query::Node->from_trine( $nodes[ $i ] );
} elsif ($nodes[ $i ]->does('Attean::API::TermOrVariable')){
$nodes[ $i ] = RDF::Query::Node->from_attean( $nodes[ $i ] );
}
}
}
return $class->_new( @nodes );
}
sub _new {
my $class = shift;
return $class->SUPER::new( @_ );
}
=item C<< as_sparql >>
Returns the SPARQL string for this algebra expression.
=cut
sub as_sparql {
my $self = shift;
my $context = shift;
my $indent = shift;
my $pred = $self->predicate;
if ($pred->isa('RDF::Trine::Node::Resource') and $pred->uri_value eq 'http://www.w3.org/1999/02/22-rdf-syntax-ns#type') {
$pred = 'a';
} else {
$pred = $pred->as_sparql( $context );
}
my $subj = $self->subject->as_sparql( $context );
my $obj = $self->object->as_sparql( $context );
my $string = sprintf(
"%s %s %s .",
$subj,
$pred,
$obj,
);
return $string;
}
=item C<< as_hash >>
Returns the query as a nested set of plain data structures (no objects).
=cut
sub as_hash {
my $self = shift;
my $context = shift;
return {
type => lc($self->type),
nodes => [ map { $_->as_hash } $self->nodes ],
};
}
=item C<< as_spin ( $model ) >>
Adds statements to the given model to represent this algebra object in the
SPARQL Inferencing Notation (L<http://www.spinrdf.org/>).
=cut
sub as_spin {
my $self = shift;
my $model = shift;
my $spin = RDF::Trine::Namespace->new('http://spinrdf.org/spin#');
my $t = RDF::Query::Node::Blank->new();
my @nodes = $self->nodes;
foreach (@nodes) {
if (blessed($_) and $_->isa('RDF::Trine::Node::Variable')) {
$_ = RDF::Query::Node::Blank->new( "variable_" . $_->name );
}
}
$model->add_statement( RDF::Trine::Statement->new($t, $spin->subject, $nodes[0]) );
$model->add_statement( RDF::Trine::Statement->new($t, $spin->predicate, $nodes[1]) );
$model->add_statement( RDF::Trine::Statement->new($t, $spin->object, $nodes[2]) );
return $t;
}
=item C<< referenced_blanks >>
Returns a list of the blank node names used in this algebra expression.
=cut
sub referenced_blanks {
my $self = shift;
my @nodes = $self->nodes;
my @blanks = grep { Carp::confess Dumper($_) unless blessed($_); $_->isa('RDF::Trine::Node::Blank') } @nodes;
return map { $_->blank_identifier } @blanks;
}
=item C<< subsumes ( $pattern ) >>
Returns true if the triple subsumes the pattern, false otherwise.
=cut
sub subsumes {
my $self = shift;
my $pattern = shift;
return 0 unless ($pattern->isa('RDF::Trine::Statement'));
foreach my $method (@node_methods) {
my $snode = $self->$method();
next if ($snode->isa('RDF::Trine::Node::Variable'));
my $pnode = $pattern->$method();
next if ($snode->equal( $pnode ));
return 0;
}
return 1;
}
=item C<< bf () >>
Returns a string representing the state of the nodes of the triple (bound or free).
=cut
sub bf {
my $self = shift;
my $bf = '';
foreach my $n ($self->nodes) {
$bf .= ($n->isa('RDF::Query::Node::Variable'))
? 'f'
: 'b';
}
return $bf;
}
=item C<< distinguish_bnode_variables >>
Returns a new Quad object with blank nodes replaced by distinguished variables.
=cut
sub distinguish_bnode_variables {
my $self = shift;
my $class = ref($self);
my @nodes = $self->nodes;
foreach my $i (0 .. $#nodes) {
if ($nodes[$i]->isa('RDF::Query::Node::Blank')) {
$nodes[$i] = $nodes[$i]->make_distinguished_variable;
}
}
return $class->new( @nodes );
}
sub _from_sse {
my $class = shift;
return RDF::Trine::Statement->from_sse( @_ );
}
=item C<< label ( $label => $value ) >>
Sets the named C<< $label >> to C<< $value >> for this triple object.
If no C<< $value >> is given, returns the current label value, or undef if none
exists.
=cut
sub label {
my $self = shift;
my $addr = refaddr($self);
my $label = shift;
if (@_) {
my $value = shift;
$TRIPLE_LABELS{ $addr }{ $label } = $value;
}
if (exists $TRIPLE_LABELS{ $addr }) {
return $TRIPLE_LABELS{ $addr }{ $label };
} else {
return;
}
}
sub DESTROY {
my $self = shift;
my $addr = refaddr( $self );
delete $TRIPLE_LABELS{ $addr };
}
1;
__END__
=back
=head1 AUTHOR
Gregory Todd Williams <gwilliams@cpan.org>
=cut
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