NAME

RDF::Trine::Iterator::Bindings - Iterator class for bindings query results

VERSION

This document describes RDF::Trine::Iterator::Bindings version 1.012

SYNOPSIS

use RDF::Trine::Iterator::Bindings;

my $iterator = RDF::Trine::Iterator::Bindings->new( \&data, \@names );
while (my $row = $iterator->next) {
  # $row is a HASHref containing variable name -> RDF Term bindings
  my @vars = keys %$row;
  print $row->{ 'var' }->as_string;
}

METHODS

Beyond the methods documented below, this class inherits methods from the RDF::Trine::Iterator class.

new ( \@results, \@names, %args )

new ( \&results, \@names, %args )

Returns a new SPARQL Result interator object. Results must be either a reference to an array containing results or a CODE reference that acts as an iterator, returning successive items when called, and returning undef when the iterator is exhausted.

materialize

Returns a materialized version of the current binding iterator. The materialization process will leave this iterator empty. The materialized iterator that is returned should be used for any future need for the iterator's data.

project ( @columns )

Returns a new stream that projects the current bindings to only the given columns.

join_streams ( $stream, $stream )

Performs a natural, nested loop join of the two streams, returning a new stream of joined results.

nested_loop_join ( $outer, $inner )

Performs a natural, nested loop join of the two streams, returning a new stream of joined results.

Note that the values from the $inner iterator are fully materialized for this join, and the results of the join are in the order of values from the $outer iterator. This suggests that:

* If sorting needs to be preserved, the $outer iterator should be used to determine the result ordering.

* If one iterator is much smaller than the other, it should likely be used as the $inner iterator since materialization will require less total memory.

sorted_by

binding_value_by_name ( $name )

Returns the binding of the named variable in the current result.

binding_value ( $i )

Returns the binding of the $i-th variable in the current result.

binding_values

Returns a list of the binding values from the current result.

binding_names

Returns a list of the binding names.

binding_name ( $i )

Returns the name of the $i-th result column.

bindings_count

Returns the number of variable bindings in the current result.

is_bindings

Returns true if the underlying result is a set of variable bindings.

as_json ( $max_size )

Returns a JSON serialization of the stream data.

as_xml ( $max_size )

Returns an XML serialization of the stream data.

as_string ( $max_size [, \$count] )

Returns a string table serialization of the stream data.

as_statements ( $pattern | @names )

Returns a RDF::Trine::Iterator::Graph with the statements of the stream.

If $pattern, an RDF::Trine::Pattern object, is given as an argument, each of its triples are instantiated with variable bindings from each row of the iterator, and returned as RDF::Trine::Statement objects from a new RDF::Trine::Iterator::Graph iterator.

If 3 variable @names are supplied, their corresponding variable bindings in each row of the iterator are used (in order) as the subject, predicate, and object of new RDF::Trine::Statement objects and returned from a new RDF::Trine::Iterator::Graph iterator.

print_xml ( $fh, $max_size )

Prints an XML serialization of the stream data to the filehandle $fh.

construct_args

Returns the arguments necessary to pass to the stream constructor _new to re-create this stream (assuming the same closure as the first argument).

DEPENDENCIES

JSON

Scalar::Util

BUGS

Please report any bugs or feature requests to through the GitHub web interface at https://github.com/kasei/perlrdf/issues.

AUTHOR

Gregory Todd Williams <gwilliams@cpan.org>

COPYRIGHT

Copyright (c) 2006-2012 Gregory Todd Williams. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.