Module: JSON::LD::Flatten

Includes:
Utils
Included in:
API
Defined in:
lib/json/ld/flatten.rb

Instance Method Summary collapse

Methods included from Utils

#add_value, #as_resource, #blank_node?, #compare_values, #graph?, #has_property, #has_value, #index?, #list?, #node?, #node_or_ref?, #node_reference?, #simple_graph?, #value?

Instance Method Details

#create_node_map(input, graphs, graph: '@default', name: nil, list: nil) ⇒ Object

This algorithm creates a JSON object node map holding an indexed representation of the graphs and nodes represented in the passed expanded document. All nodes that are not uniquely identified by an IRI get assigned a (new) blank node identifier. The resulting node map will have a member for every graph in the document whose value is another object with a member for every node represented in the document. The default graph is stored under the @default member, all other graphs are stored under their graph name.

Parameters:

  • input (Array, Hash) —

    Expanded JSON-LD input

  • graphs (Hash) —

    A map of graph name to subjects

  • graph (String) (defaults to: '@default') —

    The name of the currently active graph that the processor should use when processing.

  • name (String) (defaults to: nil) —

    The name assigned to the current input if it is a bnode

  • list (Array) (defaults to: nil) —

    List to append to, nil for none



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# File 'lib/json/ld/flatten.rb', line 19

def create_node_map(input, graphs, graph: '@default', name: nil, list: nil)
  #log_debug("node_map") {"graph: #{graph}, input: #{input.inspect}, name: #{name}"}
  case input
  when Array
    # If input is an array, process each entry in input recursively by passing item for input, node map, active graph, active subject, active property, and list.
    input.map {|o| create_node_map(o, graphs, graph: graph, list: list)}
  when Hash
    type = input['@type']
    if value?(input)
      # Rename blanknode @type
      input['@type'] = namer.get_name(type) if type && blank_node?(type)
      list << input if list
    else
      # Input is a node definition

      # spec requires @type to be named first, so assign names early
      Array(type).each {|t| namer.get_name(t) if blank_node?(t)}

      # get name for subject
      if name.nil?
        name ||= input['@id']
        name = namer.get_name(name) if blank_node?(name)
      end

      # add subject reference to list
      list << {'@id' => name} if list

      # create new subject or merge into existing one
      subject = (graphs[graph] ||= {})[name] ||= {'@id' => name}

      input.keys.kw_sort.each do |property|
        objects = input[property]
        case property
        when '@id'
          # Skip
        when '@reverse'
          # handle reverse properties
          referenced_node, reverse_map = {'@id' => name}, objects
          reverse_map.each do |reverse_property, items|
            items.each do |item|
              item_name = item['@id']
              item_name = namer.get_name(item_name) if blank_node?(item_name)
              create_node_map(item, graphs, graph: graph, name: item_name)
              add_value(graphs[graph][item_name],
                        reverse_property,
                        referenced_node,
                        property_is_array: true,
                        allow_duplicate: false)
            end
          end
        when '@graph'
          graphs[name] ||= {}
          create_node_map(objects, graphs, graph: name)
        when /^@(?!type)/
          # copy non-@type keywords
          if property == '@index' && subject['@index']
            raise JsonLdError::ConflictingIndexes,
                  "Element already has index #{subject['@index']} dfferent from #{input['@index']}" if
                  subject['@index'] != input['@index']
            subject['@index'] = input.delete('@index')
          end
          subject[property] = objects
        else
          # if property is a bnode, assign it a new id
          property = namer.get_name(property) if blank_node?(property)

          add_value(subject, property, [], property_is_array: true) if objects.empty?

          objects.each do |o|
            o = namer.get_name(o) if property == '@type' && blank_node?(o)

            case
            when node?(o) || node_reference?(o)
              id = o['@id']
              id = namer.get_name(id) if blank_node?(id)

              # add reference and recurse
              add_value(subject, property, {'@id' => id}, property_is_array: true, allow_duplicate: false)
              create_node_map(o, graphs, graph: graph, name: id)
            when list?(o)
              olist = []
              create_node_map(o['@list'], graphs, graph: graph, name: name, list: olist)
              o = {'@list' => olist}
              add_value(subject, property, o, property_is_array: true, allow_duplicate: true)
            else
              # handle @value
              create_node_map(o, graphs, graph: graph, name: name)
              add_value(subject, property, o, property_is_array: true, allow_duplicate: false)
            end
          end
        end
      end
    end
  else
    # add non-object to list
    list << input if list
  end
end