Class: Triannon::Graph

Inherits:
Object
  • Object
show all
Defined in:
lib/triannon/graph.rb

Overview

a wrapper class for RDF::Graph that adds methods specific to Triannon this is intended to be used for an RDF::Graph of a single annotation

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(rdf_graph) ⇒ Graph

instantiate this class for an RDF::Graph of a single annotation



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# File 'lib/triannon/graph.rb', line 32

def initialize(rdf_graph)
  @graph = rdf_graph
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(sym, *args, &block) ⇒ Object

send unknown methods to RDF::Graph



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# File 'lib/triannon/graph.rb', line 168

def method_missing(sym, *args, &block)
  @graph.send sym, *args, &block
end

Class Method Details

.anno_query ⇒ RDF::Query

Returns query for a subject :s with type of RDF::OpenAnnotation.Annotation.

Returns:

  • (RDF::Query) —

    query for a subject :s with type of RDF::OpenAnnotation.Annotation



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# File 'lib/triannon/graph.rb', line 23

def self.anno_query
  q = RDF::Query.new
  q << [:s, RDF.type, RDF::OpenAnnotation.Annotation]
end

.subject_statements(subject, graph) ⇒ Array[RDF::Statement]

given an RDF::Resource (an RDF::Node or RDF::URI), look for all the statements with that object

as the subject, and recurse through the graph to find all descendant statements pertaining to the subject

Parameters:

  • subject —

    the RDF object to be used as the subject in the graph query. Should be an RDF::Node or RDF::URI

  • graph (RDF::Graph)

Returns:

  • (Array[RDF::Statement]) —

    all the triples with the given subject



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# File 'lib/triannon/graph.rb', line 13

def self.subject_statements(subject, graph)
  result = []
  graph.query([subject, nil, nil]).each { |stmt|
    result << stmt
    subject_statements(stmt.object, graph).each { |s| result << s }
  }
  result.uniq
end

Instance Method Details

#annotated_at ⇒ String

Returns The datetime from the annotatedAt property, or nil.

Returns:

  • (String) —

    The datetime from the annotatedAt property, or nil



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# File 'lib/triannon/graph.rb', line 107

def annotated_at
  solution = @graph.query [nil, RDF::OpenAnnotation.annotatedAt, nil]
  if solution && solution.size == 1
    solution.first.object.to_s
  end
end

#body_chars ⇒ Array<String>

For all bodies that are of type ContentAsText, get the characters as a single String in the returned Array.

Returns:

  • (Array<String>) —

    body chars as Strings, in an Array (one element for each contentAsText body)



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# File 'lib/triannon/graph.rb', line 93

def body_chars
  result = []
  q = RDF::Query.new
  q << [nil, RDF::OpenAnnotation.hasBody, :body]
  q << [:body, RDF.type, RDF::Content.ContentAsText]
  q << [:body, RDF::Content.chars, :body_chars]
  solns = @graph.query q
  solns.each { |soln| 
    result << soln.body_chars.value
  }
  result
end

#id_as_url ⇒ String

Returns the id of this annotation as a url string, or nil if it is a Node.

Returns:

  • (String) —

    the id of this annotation as a url string, or nil if it is a Node



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# File 'lib/triannon/graph.rb', line 55

def id_as_url
  solution = @graph.query self.class.anno_query
  if solution && solution.size == 1
    rdf_resource = solution.first.s
    rdf_resource.to_s if rdf_resource.is_a?(RDF::URI)
    # TODO:  raise exception if not a URI?
  end
end

#jsonld_iiif ⇒ Object

Returns json-ld representation of graph with IIIF context as a url.

Returns:

  • json-ld representation of graph with IIIF context as a url



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# File 'lib/triannon/graph.rb', line 45

def jsonld_iiif
  inline_context = @graph.dump(:jsonld, :context => Triannon::JsonldContext::IIIF_CONTEXT_URL)
  hash_from_json = JSON.parse(inline_context)
  hash_from_json["@context"] = Triannon::JsonldContext::IIIF_CONTEXT_URL
  hash_from_json.to_json
end

#jsonld_oa ⇒ Object

Returns json-ld representation of graph with OpenAnnotation context as a url.

Returns:

  • json-ld representation of graph with OpenAnnotation context as a url



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# File 'lib/triannon/graph.rb', line 37

def jsonld_oa
  inline_context = @graph.dump(:jsonld, :context => Triannon::JsonldContext::OA_DATED_CONTEXT_URL)
  hash_from_json = JSON.parse(inline_context)
  hash_from_json["@context"] = Triannon::JsonldContext::OA_DATED_CONTEXT_URL
  hash_from_json.to_json
end

#make_null_relative_uri_out_of_blank_node ⇒ Object

transform an outer blank node into a null relative URI



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# File 'lib/triannon/graph.rb', line 148

def make_null_relative_uri_out_of_blank_node
  anno_stmts = @graph.query([nil, RDF.type, RDF::OpenAnnotation.Annotation])
  anno_rdf_obj = anno_stmts.first.subject
  if anno_rdf_obj.is_a?(RDF::Node)
    # use null relative URI representation of blank node
    anno_subject = RDF::URI.new
  else # it's already a URI
    anno_subject = anno_rdf_obj
  end
  Triannon::Graph.subject_statements(anno_rdf_obj, @graph).each { |s|
    if s.subject == anno_rdf_obj && anno_subject != anno_rdf_obj
      @graph << RDF::Statement({:subject => anno_subject,
                           :predicate => s.predicate,
                           :object => s.object})
      @graph.delete s
    end
  }
end

#motivated_by ⇒ Array<String>

Returns Array of urls expressing the OA motivated_by values.

Returns:

  • (Array<String>) —

    Array of urls expressing the OA motivated_by values



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# File 'lib/triannon/graph.rb', line 65

def motivated_by
  motivations = []
  q = self.class.anno_query.dup
  q << [:s, RDF::OpenAnnotation.motivatedBy, :motivated_by]
  solution = @graph.query q
  if solution && solution.size > 0
    solution.each {|res|
      motivations << res.motivated_by.to_s
    }
  end
  # TODO:  raise exception if none? (validation)
  motivations
end

#predicate_urls(predicate) ⇒ Array<String>

Returns urls for the predicate, as an Array of Strings.

Parameters:

  • predicate (RDF::URI) —

    either RDF::OpenAnnotation.hasTarget or RDF::OpenAnnotation.hasBody

Returns:

  • (Array<String>) —

    urls for the predicate, as an Array of Strings



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# File 'lib/triannon/graph.rb', line 81

def predicate_urls(predicate)
  urls = []
  predicate_solns = @graph.query [nil, predicate, nil]
  predicate_solns.each { |predicate_stmt |
    predicate_obj = predicate_stmt.object
    urls << predicate_obj.to_str.strip if predicate_obj.is_a?(RDF::URI)
  }
  urls
end

#remove_has_body_statements ⇒ Object

remove all RDF::OpenAnnotation.hasBody statements and any other statements associated with body objects



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# File 'lib/triannon/graph.rb', line 126

def remove_has_body_statements
  remove_predicate_and_its_object_statements RDF::OpenAnnotation.hasBody
end

#remove_has_target_statements ⇒ Object

remove all RDF::OpenAnnotation.hasTarget statements and any other statements associated with body objects



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# File 'lib/triannon/graph.rb', line 131

def remove_has_target_statements
  remove_predicate_and_its_object_statements RDF::OpenAnnotation.hasTarget
end

#remove_non_base_statements ⇒ Object

remove all RDF::OpenAnnotation.hasBody and .hasTarget statements

and any other statements associated with body and target objects, 
leaving all statements to be stored as part of base object in LDP store



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# File 'lib/triannon/graph.rb', line 120

def remove_non_base_statements
  remove_has_target_statements
  remove_has_body_statements
end

#remove_predicate_and_its_object_statements(predicate) ⇒ Object

remove all such predicate statements and any other statements associated with predicates’ objects



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# File 'lib/triannon/graph.rb', line 136

def remove_predicate_and_its_object_statements(predicate)
  predicate_stmts = @graph.query([nil, predicate, nil])
  predicate_stmts.each { |pstmt|
    pred_obj = pstmt.object
    Triannon::Graph.subject_statements(pred_obj, @graph).each { |s|
      @graph.delete s
    } unless !Triannon::Graph.subject_statements(pred_obj, @graph)
    @graph.delete pstmt
  }
end