Method: ActiveTriples::Relation#build

Defined in:
lib/active_triples/relation.rb

#build(attributes = {}) ⇒ Object

Builds a node with the given attributes, adding it to the relation.

Nodes are built using the configured class_name for the relation. Attributes passed in the Hash argument are set on the new node through ‘RDFSource#attributes=`. If the attribute keys are not valid properties on the built node, we raise an error.

@todo: clarify class behavior; it is actually tied to type, in some cases.

Examples:

building an empty generic node

resource = ActiveTriples::Resource.new
resource.resource.get_values(RDF::Vocab::DC.relation).build
# => #<ActiveTriples::Resource:0x2b0(#<ActiveTriples::Resource:0x005>)>)

resource.dump :ttl
# => "\n [ <http://purl.org/dc/terms/relation> []] .\n"

building a node with attributes

class WithRelation
  include ActiveTriples::RDFSource
  property :relation, predicate:  RDF::Vocab::DC.relation,
    class_name: 'WithTitle'
end

class WithTitle
  include ActiveTriples::RDFSource
  property :title, predicate: RDF::Vocab::DC.title
end

resource = WithRelation.new
attributes = { id: 'http://ex.org/moomin', title: 'moomin' }

resource.get_values(:relation).build(attributes)
# => #<ActiveTriples::Resource:0x2b0(#<ActiveTriples::Resource:0x005>)>)

resource.dump :ttl
# => "\n<http://ex.org/moomin> <http://purl.org/dc/terms/title> \"moomin\" .\n\n [ <http://purl.org/dc/terms/relation> <http://ex.org/moomin>] .\n"

Parameters:

  • attributes (Hash) (defaults to: {}) —

    a hash of attribute names and values for the built node.

See Also:



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# File 'lib/active_triples/relation.rb', line 190

def build(attributes={})
  new_subject = attributes.fetch('id') { RDF::Node.new }

  make_node(new_subject).tap do |node|
    node.attributes = attributes.except('id')
    if parent.kind_of? List::ListResource
      parent.list << node
    elsif node.kind_of? RDF::List
      self.push node.rdf_subject
    else
      self.push node
    end
  end
end