NAME

RDF::Query::ServiceDescription - Class for describing federated query data sources.

VERSION

This document describes RDF::Query::ServiceDescription version 2.201, released 30 January 2010.

METHODS

new ( $service_uri, %data )

new_from_uri ( $url )

Creates a new service description object using the DARQ-style service description data located at $url.

new_with_model ( $model )

Creates a new service description object using the DARQ-style service description data loaded in the supplied $model object.

url

Returns the endpoint URL of the service.

size

Returns the number of triples the service claims to have.

label

Returns the label of the service.

definitive

Returns true if the endpoint claims to have definitive information.

capabilities

Returns an ARRAY reference of capabilities (as HASH references) of the service. Each capability will contain information on size, selectivity, any subject-object filter, and required predicate, with the following classes:

$capability->{object_selectivity} # RDF::Trine::Node::Literal xsd:double
$capability->{sofilter} # RDF::Query::Expression
$capability->{size} # RDF::Trine::Node::Literal xsd:integer
$capability->{pred} # RDF::Trine::Node::Resource

patterns

Returns an ARRAY reference of RDF::Query::Algebra::BasicGraphPattern objects representing common patterns used by the endpoint.

computed_statement_generator

Returns a closure appropriate for passing to RDF::Query->add_computed_statement_generator to generate statement iterators for the remote service.

This closure takes ($query, $bridge, \%bound, $subj, $pred, $obj [, $context ] ) as arguments and returns either undef if no statements can be generated given the arguments, or a RDF::Trine::Iterator::Graph iterator containing statements matching $subj, $pred, $obj [, $context ].

answers_triple_pattern ( $triple )

Returns true if the service described by this object can answer queries comprised of the supplied triple pattern.

AUTHOR

Gregory Todd Williams <gwilliams@cpan.org>