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Attean::API::Model - RDF Model

Attean::API::Model(3pm) User Contributed Perl Documentation Attean::API::Model(3pm)

NAME

Attean::API::Model - RDF Model

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.

BUGS

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

SEE ALSO

<http://www.perlrdf.org/>

AUTHOR

Gregory Todd Williams "<gwilliams@cpan.org>" 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.
2017-10-02 perl v5.26.0