writer.rb in rdf-json-0.0.1

- old
+ new
@@ -1,11 +1,90 @@
 module RDF::JSON
   ##
   # RDF/JSON serializer.
   #
+  # @example Obtaining an RDF/JSON writer class
+  #   RDF::Writer.for(:json)         #=> RDF::JSON::Writer
+  #   RDF::Writer.for("spec/data/test.json")
+  #   RDF::Writer.for(:file_name      => "spec/data/test.json")
+  #   RDF::Writer.for(:file_extension => "json")
+  #   RDF::Writer.for(:content_type   => "application/json")
+  #
+  # @example Serializing RDF statements into an RDF/JSON file
+  #   RDF::JSON::Writer.open("spec/data/test.json") do |writer|
+  #     graph.each_statement do |statement|
+  #       writer << statement
+  #     end
+  #   end
+  #
+  # @example Serializing RDF statements into an RDF/JSON string
+  #   RDF::JSON::Writer.buffer do |writer|
+  #     graph.each_statement do |statement|
+  #       writer << statement
+  #     end
+  #   end
+  #
   # @see http://n2.talis.com/wiki/RDF_JSON_Specification
   class Writer < RDF::Writer
     format RDF::JSON::Format
 
-    # TODO
-  end
-end
+    ##
+    # Stores the RDF/JSON representation of a triple.
+    #
+    # @param  [RDF::Resource] subject
+    # @param  [RDF::URI]      predicate
+    # @param  [RDF::Value]    object
+    # @return [void]
+    # @see    #write_epilogue
+    def write_triple(subject, predicate, object)
+      s = subject.to_s
+      p = predicate.to_s
+      o = object.is_a?(RDF::Value) ? object : RDF::Literal.new(object)
+      @json       ||= {}
+      @json[s]    ||= {}
+      @json[s][p] ||= []
+      @json[s][p] << o.to_rdf_json
+    end
+
+    ##
+    # Outputs the RDF/JSON representation of all stored triples.
+    #
+    # @return [void]
+    # @see    #write_triple
+    def write_epilogue
+      puts @json.to_json
+    end
+
+    ##
+    # Returns the RDF/JSON representation of a blank node.
+    #
+    # @param  [RDF::Node] value
+    # @param  [Hash{Symbol => Object}] options
+    # @return [String]
+    def format_node(value, options = {})
+      value.to_json
+    end
+
+    ##
+    # Returns the RDF/JSON representation of a URI reference.
+    #
+    # @param  [RDF::URI] value
+    # @param  [Hash{Symbol => Object}] options
+    # @return [String]
+    def format_uri(value, options = {})
+      value.to_json
+    end
+
+    ##
+    # Returns the RDF/JSON representation of a literal.
+    #
+    # @param  [RDF::Literal, String, #to_s] value
+    # @param  [Hash{Symbol => Object}] options
+    # @return [String]
+    def format_literal(value, options = {})
+      case value
+        when RDF::Literal then value.to_json
+        else RDF::Literal.new(value).to_json
+      end
+    end
+  end # class Writer
+end # module RDF::JSON