NAME

RDF::Trine::Iterator - Iterator class for SPARQL query results

VERSION

This document describes RDF::Trine::Iterator version 1.018.

SYNOPSIS

    use RDF::Trine::Iterator;
    my $iterator = RDF::Trine::Iterator->new( \&data, 'bindings', \@names );
    while (my $row = $iterator->next) {
        my @vars        = keys %$row;
        # do something with @vars
    }

METHODS

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

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

Returns a new SPARQL Result interator object. Results must be either an 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.

$type should be one of: bindings, boolean, graph.

type

Returns the underlying result type (boolean, graph, bindings).

is_boolean

Returns true if the underlying result is a boolean value.

is_bindings

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

is_graph

Returns true if the underlying result is an RDF graph.

to_string ( $format )

Returns a string representation of the stream data in the specified $format. If $format is missing, defaults to XML serialization. Other options are:

  http://www.w3.org/2001/sw/DataAccess/json-sparql/

from_string ( $xml )

Returns a new iterator using the supplied XML string in the SPARQL XML Results format.

from_bytes ( $xml )

Returns a new iterator using the supplied XML byte sequence (note: not character data) in the SPARQL XML Results format.

from_json ( $json )

next_result

next

Returns the next item in the stream.

peek

Returns the next value from the iterator without consuming it. The value will remain in queue until the next call to next.

current

Returns the current item in the stream.

end

finished

Returns true if the end of the stream has been reached, false otherwise.

open

Returns true if the first element of the stream has been retrieved, false otherwise.

close

Closes the stream. Future attempts to retrieve data from the stream will act as if the stream had been exhausted.

concat ( $stream )

Returns a new stream resulting from the concatenation of the referant and the argument streams. The new stream uses the stream type, and optional binding names and <%args> from the referant stream.

seen_count

Returns the count of elements that have been returned by this iterator at the point of invocation.

get_boolean

Returns the boolean value of the first item in the stream.

get_all

Returns an array containing all the items in the stream.

construct_args

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

each ( \&callback )

Calls the callback function once for each item in the iterator, passing the item as an argument to the function. Any arguments to each beyond the callback function will be passed as supplemental arguments to the callback function.

FUNCTIONS

sgrep { COND } $stream

smap { EXPR } $stream

swatch { EXPR } $stream

DEPENDENCIES

JSON

Scalar::Util

XML::SAX

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.