VERSION

This document describes Attean::API::Model version 0.017

DESCRIPTION

The Attean::API::Model role defines a common API for all RDF models to conform to. It is provides a consistent interface for probing, counting, and retrieving Attean::API::Quads matching a pattern, as well as related functionality such as enumerating the graph names, and extracting structured data from the models' quads.

REQUIRED METHODS

The following methods are required by the Attean::API::Model role:

"get_quads( $subject, $predicate, $object, $graph )"

Returns an Attean::API::Iterator for quads in the model that match the supplied $subject, $predicate, $object, and $graph.

Any of these terms may be:

* An Attean::API::Term object, in which case matching is equality-based

* A Attean::API::Variable object or "undef", in which case that term will be considered as a wildcard for the purposes of matching

* An ARRAY reference of Attean::API::Term objects, in which case the matching will be equality-based on the disjunction of the supplied terms

The returned iterator conforms to both Attean::API::Iterator and Attean::API::QuadIterator.

"count_quads( $subject, $predicate, $object, $graph )"

Returns the number of quads in the model matching the supplied pattern (using the same matching semantics as "get_quads").

"get_graphs"

Returns an Attean::API::Iterator of distinct Attean::API::Term objects that are used in the graph position of quads in the model.

METHODS

The Attean::API::Model role provides default implementations of the following methods:

"get_bindings( $subject, $predicate, $object, $graph )"

Returns an Attean::API::Iterator of Attean::API::Result objects corresponding to quads in the model matching the supplied pattern. For each Attean::API::Variable in the pattern list, a mapping will be present in the corresponding result object. For example, "$model->get_bindings( variable('s') )" will return an iterator of results containing just a mapping from 's' to subjects of all quads in the model.

"get_list( $graph, $head )"

Returns an Attean::API::Iterator of Attean::API::Term objects that are members of the rdf:List with the specified $head (and matching restricted to only the specified $graph).

"get_sequence( $graph, $head )"

Returns an Attean::API::Iterator of Attean::API::Term objects that are members of the rdf:Sequence with the specified $head (and matching restricted to only the specified $graph).

"subjects( $predicate, $object, $graph )"

Returns an Attean::API::Iterator of Attean::API::Term objects of all subjects of quads matching the supplied pattern (using the same matching semantics as "get_quads").

"predicates( $subject, $object, $graph )"

Returns an Attean::API::Iterator of Attean::API::Term objects of all predicates of quads matching the supplied pattern (using the same matching semantics as "get_quads" with an "undef" predicate).

"objects( $subject, $predicate, $graph )"

Returns an Attean::API::Iterator of Attean::API::Term objects of all objects of quads matching the supplied pattern (using the same matching semantics as "get_quads" with an "undef" object).

"graphs( $subject, $predicate, $object )"

Returns an Attean::API::Iterator of Attean::API::Term objects of all graphs of quads matching the supplied pattern (using the same matching semantics as "get_quads" with an "undef" graph).

"graph_nodes( $graph )"

Returns an Attean::API::Iterator of Attean::API::Term objects of unique subjects and objects present in the specified $graph.

AUTHOR

Gregory Todd Williams "<[email protected]>"

COPYRIGHT

Copyright (c) 2014--2016 Gregory Todd Williams. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.