NAME

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

VERSION

       This document describes RDF::Query::ServiceDescription version 2.916.

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>