Class: RDFObject::Resource

Inherits:
OpenStruct
  • Object
show all
Defined in:
lib/rdf_objects/rdf_resource.rb

Class Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(uri) ⇒ Resource

Returns a new instance of Resource.



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# File 'lib/rdf_objects/rdf_resource.rb', line 40

def initialize(uri)        
  if uri.could_be_a_safe_curie?
    uri = Curie.parse uri
  end
  super(:uri=>uri)
  self.class.register(self)
end

Class Attribute Details

.instances ⇒ Object (readonly)

Returns the value of attribute instances.



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# File 'lib/rdf_objects/rdf_resource.rb', line 9

def instances
  @instances
end

Class Method Details

.exists?(uri) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rdf_objects/rdf_resource.rb', line 30

def exists?(uri)
  instances
  if @instances.has_key?(uri)
    true
  else
    false
  end
end

.new(uri) ⇒ Object 



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# File 'lib/rdf_objects/rdf_resource.rb', line 207

def self.new(uri)
  if self.exists?(uri)
    return self.instances[uri]
  end
  super(uri)
end

.register(resource) ⇒ Object 



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# File 'lib/rdf_objects/rdf_resource.rb', line 20

def register(resource)
  instances
  @instances[resource.uri] = resource
end

.remove(resource) ⇒ Object 



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# File 'lib/rdf_objects/rdf_resource.rb', line 25

def remove(resource)
  instances      
  @instances.delete(resource.uri)
end

.reset! ⇒ Object 



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# File 'lib/rdf_objects/rdf_resource.rb', line 16

def reset!
  @instances = {}
end

Instance Method Details

#[](uri) ⇒ Object 



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# File 'lib/rdf_objects/rdf_resource.rb', line 77

def [](uri)
  curie = case
  when uri.could_be_a_safe_curie? then Curie.new_from_curie(uri)
  when Curie.curie_from_uri(uri) then Curie.curie_from_uri(uri)
  else 
    return nil
  end
  vocab = self.send(curie.prefix.to_sym)
  return nil unless vocab
  return vocab if curie.reference.empty?
  return vocab[curie.reference]
end

#assert(predicate, object) ⇒ Object 



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# File 'lib/rdf_objects/rdf_resource.rb', line 48

def assert(predicate, object)
  curied_predicate = case
  when predicate.could_be_a_safe_curie? then Curie.new_from_curie(predicate)
  when Curie.curie_from_uri(predicate) then Curie.curie_from_uri(predicate)
  else Curie.create_from_uri(predicate)
  end
  self.register_vocabulary(curied_predicate.prefix)
  pred_attr = self.send(curied_predicate.prefix.to_sym)
  return if assertion_exists?(predicate, object)
  if pred_attr[curied_predicate.reference]
    unless pred_attr[curied_predicate.reference].is_a?(Array)
      pred_attr[curied_predicate.reference] = [pred_attr[curied_predicate.reference]]
    end
    pred_attr[curied_predicate.reference] << object
  else
    pred_attr[curied_predicate.reference] = object
  end
end

#assertion_exists?(predicate, object) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rdf_objects/rdf_resource.rb', line 67

def assertion_exists?(predicate, object)
  return false unless self[predicate]
  if self[predicate].is_a?(Array)
    return true if self[predicate].index(object)
  else
    return true if self[predicate] == object
  end
  return false
end

#describe ⇒ Object 



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# File 'lib/rdf_objects/rdf_resource.rb', line 107

def describe
  rdf = HTTPClient.fetch(self.uri)
  Parser.parse(rdf)
end

#empty_graph? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rdf_objects/rdf_resource.rb', line 112

def empty_graph?
  Curie.get_mappings.each do | prefix, uri |
    return false if self.respond_to?(prefix.to_sym)
  end
  return true
end

#prefix_for(uri) ⇒ Object 



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# File 'lib/rdf_objects/rdf_resource.rb', line 90

def prefix_for(uri)
  Curie.prefix_for(uri)
end

#register_vocabulary(name) ⇒ Object 



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# File 'lib/rdf_objects/rdf_resource.rb', line 94

def register_vocabulary(name)
  return if self.respond_to?(name.to_sym)
  self.new_ostruct_member(name)
  self.send("#{name}=".to_sym, {})
end

#relate(predicate, resource) ⇒ Object 



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# File 'lib/rdf_objects/rdf_resource.rb', line 100

def relate(predicate, resource)
  unless resource.is_a?(self.class)
    resource = self.class.new(resource)
  end
  self.assert(predicate, resource)
end

#to_rss ⇒ Object 



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# File 'lib/rdf_objects/rdf_resource.rb', line 162

def to_rss
  doc = Builder::XmlMarkup.new
  xmlns = {}
  i = 1
  @namespaces.each do | ns |
    next if ns == 'http://www.w3.org/1999/02/22-rdf-syntax-ns#'
    xmlns["xmlns:n#{i}"] = ns
    i += 1
  end
  xmlns["xmlns:rss"] = "http://purl.org/rss/1.0/"
  doc.rdf :RDF, xmlns do | rdf |
    rdf.item :about=>uri do | item |
      self.instance_variables.each do | ivar |
        next unless ivar =~ /^@n[0-9]*_/
        prefix, tag = ivar.split('_',2)
        attrs = {}
        curr_attr = self.instance_variable_get("#{ivar}")
        prefix.sub!(/^@/,'')
        prefix = 'rdf' if prefix == 'n0'
        unless curr_attr.is_a?(Array)
          curr_attr = [curr_attr]
        end
        curr_attr.each do | val |
          if val.is_a?(RDFResource)
            attrs['rdf:resource'] = val.uri
          end
          if @modifiers[val.object_id]
            if @modifiers[val.object_id][:language]
              attrs['xml:lang'] = @modifiers[val.object_id][:language]
            end
            if @modifiers[val.object_id][:type]
              attrs['rdf:datatype'] = @modifiers[val.object_id][:type]
            end          
          end
          unless attrs['rdf:resource']
            item.tag!("#{prefix}:#{tag}", attrs, val)
          else
            item.tag!("#{prefix}:#{tag}", attrs)
          end
        end
      end
    end
  end
  doc.target!
end

#to_xml ⇒ Object 



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# File 'lib/rdf_objects/rdf_resource.rb', line 119

def to_xml
  doc = Builder::XmlMarkup.new
  xmlns = {}
  i = 1
  @namespaces.each do | ns |
    next if ns == 'http://www.w3.org/1999/02/22-rdf-syntax-ns#'
    xmlns["xmlns:n#{i}"] = ns
    i += 1
  end
  doc.rdf :Description,xmlns.merge({:about=>uri}) do | rdf |
    self.instance_variables.each do | ivar |
      next unless ivar =~ /^@n[0-9]*_/
      prefix, tag = ivar.split('_',2)
      attrs = {}
      curr_attr = self.instance_variable_get("#{ivar}")
      prefix.sub!(/^@/,'')
      prefix = 'rdf' if prefix == 'n0'
      unless curr_attr.is_a?(Array)
        curr_attr = [curr_attr]
      end
      curr_attr.each do | val |
        if val.is_a?(RDFResource)
          attrs['rdf:resource'] = val.uri
        end
        if @modifiers[val.object_id]
          if @modifiers[val.object_id][:language]
            attrs['xml:lang'] = @modifiers[val.object_id][:language]
          end
          if @modifiers[val.object_id][:type]
            attrs['rdf:datatype'] = @modifiers[val.object_id][:type]
          end          
        end
        unless attrs['rdf:resource']
          rdf.tag!("#{prefix}:#{tag}", attrs, val)
        else
          rdf.tag!("#{prefix}:#{tag}", attrs)
        end
      end
    end
  end
  doc.target!
end