/// <summary> /// Applies the Namespace Attributes of an Element Event to the Namespace Map /// </summary> /// <param name="context">Parser Context</param> /// <param name="evt">Element Event</param> private void ApplyNamespaces(RdfXmlParserContext context, ElementEvent evt) { if (!evt.BaseUri.Equals(String.Empty)) { Uri baseUri = UriFactory.Create(Tools.ResolveUri(evt.BaseUri, context.BaseUri.ToSafeString())); context.BaseUri = baseUri; if (!context.Handler.HandleBaseUri(baseUri)) ParserHelper.Stop(); } foreach (NamespaceAttributeEvent ns in evt.NamespaceAttributes) { if (!context.Namespaces.HasNamespace(ns.Prefix) || !context.Namespaces.GetNamespaceUri(ns.Prefix).ToString().Equals(ns.Uri)) { context.Namespaces.AddNamespace(ns.Prefix, UriFactory.Create(ns.Uri)); if (!context.Handler.HandleNamespace(ns.Prefix, UriFactory.Create(ns.Uri))) ParserHelper.Stop(); } } }
/// <summary> /// Implementation of the RDF/XML Grammar Production 'RDF' /// </summary> /// <param name="context">Parser Context</param> /// <param name="element">RDF Element to apply Production to</param> private void GrammarProductionRDF(RdfXmlParserContext context, ElementEvent element) { //Tracing if (this._traceparsing) { this.ProductionTrace("RDF"); } //Check Uri is correct (using the QName for simplicity) if (!element.QName.Equals("rdf:RDF") && !element.QName.Equals(":RDF")) { throw ParserHelper.Error("Unexpected Node '" + element.QName + "', an 'rdf:RDF' node was expected", "RDF", element); } //Check has no Attributes if (element.Attributes.Count > 0) { throw ParserHelper.Error("Root Node should not contain any attributes other than XML Namespace Declarations", "RDF", element); } //Apply Namespaces this.ApplyNamespaces(context, element); //Build a Sublist of all Nodes up to the matching EndElement IEventQueue subevents = new EventQueue(); IRdfXmlEvent next; //Make sure we discard the current ElementEvent which will be at the front of the queue context.Events.Dequeue(); //Gather the Sublist while (context.Events.Count > 1) { subevents.Enqueue(context.Events.Dequeue()); } //Call the NodeElementList Grammer Production this.GrammarProductionNodeElementList(context, subevents); //Next Event in queue should be an EndElementEvent or we Error next = context.Events.Dequeue(); if (!(next is EndElementEvent)) { throw ParserHelper.Error("Unexpected Event '" + next.GetType().ToString() + "', an EndElementEvent was expected", "RDF", element); } }
/// <summary> /// Reads RDF/XML syntax from some Input using a RDF Handler /// </summary> /// <param name="handler">RDF Handler to use</param> /// <param name="input">Input to read from</param> public void Load(IRdfHandler handler, TextReader input) { if (handler == null) throw new RdfParseException("Cannot read RDF into a null RDF Handler"); if (input == null) throw new RdfParseException("Cannot read RDF from a null TextReader"); try { //Silverlight only supports XmlReader not the full XmlDocument API #if !NO_XMLDOM if (this._mode == RdfXmlParserMode.DOM) { //Load XML from Stream XmlDocument doc = new XmlDocument(); doc.Load(input); //Create a new Parser Context and Parse RdfXmlParserContext context = new RdfXmlParserContext(handler, doc, this._traceparsing); this.Parse(context); } else { #endif RdfXmlParserContext context = new RdfXmlParserContext(handler, input); this.Parse(context); #if !NO_XMLDOM } #endif } catch (XmlException xmlEx) { //Wrap in a RDF Parse Exception throw new RdfParseException("Unable to Parse this RDF/XML since System.Xml was unable to parse the document, see Inner Exception for details", new PositionInfo(xmlEx.LineNumber, xmlEx.LinePosition), xmlEx); } catch (IOException ioEx) { //Wrap in a RDF Parse Exception throw new RdfParseException("Unable to Parse this RDF/XML due to an IO Exception, see Inner Exception for details", ioEx); } catch (Exception) { //Throw unexpected errors upwards as-is throw; } finally { try { input.Close(); } catch { //Ignore exceptions here - just trying to clean up properly } } }
/// <summary> /// Given an XML Node that is the Root of the RDF/XML section of the Document Tree creates the RootEvent and generates the rest of the Event Tree by recursive calls to the <see cref="GenerateEvents">GenerateEvents</see> method /// </summary> /// <param name="context">Parser Context</param> /// <param name="docEl">XML Node that is the Root of the RDF/XML section of the Document Tree</param> /// <returns></returns> private RootEvent GenerateEventTree(RdfXmlParserContext context, XmlNode docEl) { //Get the Document Element //XmlNode docEl = document.DocumentElement; //Generate a Root Event and Element Event from it RootEvent root = new RootEvent(docEl.BaseURI, docEl.OuterXml); if (docEl.BaseURI.Equals(String.Empty)) { if (context.BaseUri != null) { root.BaseUri = context.BaseUri.ToString(); } } ElementEvent element = new ElementEvent(docEl.LocalName, docEl.Prefix, root.BaseUri, docEl.OuterXml); //Initialise Language Settings root.Language = String.Empty; element.Language = root.Language; //Set as Document Element and add as only Child root.DocumentElement = element; root.Children.Add(element); #region Attribute Processing //Go through attributes looking for XML Namespace Declarations foreach (XmlAttribute attr in docEl.Attributes) { if (attr.Prefix.Equals("xmlns") || attr.Name == "xmlns") { //Define a Namespace String prefix = attr.LocalName; if (prefix.Equals("xmlns")) prefix = String.Empty; String uri; if (attr.Value.StartsWith("http://")) { //Absolute Uri uri = attr.Value; } else if (!root.BaseUri.Equals(String.Empty)) { //Relative Uri with a Base Uri to resolve against //uri = root.BaseUri + attr.Value; uri = Tools.ResolveUri(attr.Value, root.BaseUri); } else { //Relative Uri with no Base Uri throw new RdfParseException("Cannot resolve a Relative Namespace URI since there is no in-scope Base URI"); } context.Namespaces.AddNamespace(prefix, new Uri(uri)); } else if (attr.Name == "xml:base") { //Set the Base Uri String baseUri = attr.Value; if (RdfXmlSpecsHelper.IsAbsoluteURI(baseUri)) { //Absolute Uri root.BaseUri = baseUri; } else if (!element.BaseUri.Equals(String.Empty)) { //Relative Uri with a Base Uri to resolve against //root.BaseUri += baseUri; root.BaseUri = Tools.ResolveUri(baseUri, root.BaseUri); } else { //Relative Uri with no Base Uri throw new RdfParseException("Cannot resolve a Relative Base URI since there is no in-scope Base URI"); } element.BaseUri = root.BaseUri; } } #endregion //Iterate over Children foreach (XmlNode child in docEl.ChildNodes) { //Ignore Irrelevant Node Types if (this.IsIgnorableNode(child)) { continue; } //Generate an Event for the Child Node ElementEvent childEvent = this.GenerateEvents(context, child, element); element.Children.Add(childEvent); } //Return the Root Event return root; }
/// <summary> /// Takes the Event Tree and Flattens it into a Queue as per the rules laid out in the RDF/XML Specification /// </summary> /// <param name="context">Parser Context</param> /// <param name="evt">Event which is the Root of the Tree (not necessarily a RootEvent)</param> /// <param name="nesting">A numeric value used for Parser Tracing to indicate nesting levels of the Event Tree</param> private void FlattenEventTree(RdfXmlParserContext context, IRdfXmlEvent evt, int nesting) { //Add to Queue context.Events.Enqueue(evt); if (context.TraceParsing) { Console.Write(nesting + " " + evt.GetType().ToString()); } //Iterate over Children where present if (evt is RootEvent) { RootEvent root = (RootEvent)evt; if (context.TraceParsing) { Console.WriteLine(""); } foreach (IRdfXmlEvent childEvent in root.Children) { this.FlattenEventTree(context, childEvent, nesting + 1); } //No End after a RootEvent return; } else if (evt is ElementEvent) { ElementEvent element = (ElementEvent)evt; if (context.TraceParsing) { Console.WriteLine(" " + element.Namespace + ":" + element.LocalName); } if (element.Children.Count > 0) { foreach (IRdfXmlEvent childEvent in element.Children) { this.FlattenEventTree(context, childEvent, nesting + 1); } } } else if (evt is TextEvent) { TextEvent text = (TextEvent)evt; if (context.TraceParsing) { Console.WriteLine(" " + text.Value); } //No additional End after a Text Event return; } else if (evt is TypedLiteralEvent) { TypedLiteralEvent tlit = (TypedLiteralEvent)evt; if (context.TraceParsing) { Console.WriteLine(); } //No additional End after a Text Event return; } //Add an End Element Event to the Queue EndElementEvent end = new EndElementEvent(); context.Events.Enqueue(end); if (context.TraceParsing) { String endDescrip = String.Empty; if (evt is ElementEvent) { ElementEvent temp = (ElementEvent)evt; endDescrip = " " + temp.QName; } Console.WriteLine(nesting + " " + end.GetType().ToString() + endDescrip); } }
/// <summary> /// Implementation of the RDF/XML Grammar Production 'literalPropertyElt' /// </summary> /// <param name="context">Parser Context</param> /// <param name="eventlist">Queue of Events that make up the Literal Property Element and its Children</param> /// <param name="parent">Parent Event (ie. Node) of the Property Element</param> private void GrammarProductionLiteralPropertyElement(RdfXmlParserContext context, IEventQueue<IRdfXmlEvent> eventlist, IRdfXmlEvent parent) { //Tracing if (this._traceparsing) { this.ProductionTracePartial("Literal Property Element"); } //Get the 3 Events (should only be three) IRdfXmlEvent first, middle, last; first = eventlist.Dequeue(); middle = eventlist.Dequeue(); last = eventlist.Dequeue(); //If Queue is non-empty then Error if (eventlist.Count > 0) { throw ParserHelper.Error("Too many events encountered while trying to parse a Literal Property Element", first); } ElementEvent element = (ElementEvent)first; if (this._traceparsing) this.ProductionTracePartial(element); //Apply Namespaces this.ApplyNamespaces(context, element); //Validate that the middle event is a TextEvent if (!(middle is TextEvent)) { throw ParserHelper.Error("Unexpected event '" + middle.GetType().ToString() + "', expected a TextEvent in a Literal Property Element", middle); } TextEvent text = (TextEvent)middle; //Validate the Attributes String ID = String.Empty; String datatype = String.Empty; if (element.Attributes.Count > 2) { throw ParserHelper.Error("A Literal Property Element contains too many attributes, only rdf:ID and rdf:datatype are permitted", element); } else { //Only rdf:ID and rdf:datatype allowed foreach (AttributeEvent a in element.Attributes) { if (RdfXmlSpecsHelper.IsIDAttribute(a)) { ID = "#" + a.Value; } else if (RdfXmlSpecsHelper.IsDataTypeAttribute(a)) { datatype = a.Value; } else { throw ParserHelper.Error("A Literal Property Element contains an unexpected attribute, only rdf:ID and rdf:datatype are permitted", element); } } } //Create the Nodes for the Graph INode subj, pred, obj; //Get the Subject from the Parent ElementEvent parentEl = (ElementEvent)parent; subj = parentEl.SubjectNode; //Validate the ID (if any) if (!ID.Equals(String.Empty)) { this.ValidateID(context, ID.Substring(1), subj); } //Create a Predicate from this Element pred = this.Resolve(context, element);//context.Handler.CreateUriNode(element.QName); //Create an Object from the Text Event if (datatype.Equals(String.Empty)) { //No Type with possible Language if (element.Language.Equals(String.Empty)) { obj = context.Handler.CreateLiteralNode(text.Value); } else { obj = context.Handler.CreateLiteralNode(text.Value, element.Language); } } else { //Typed //Resolve the Datatype Uri UriReferenceEvent dtref = new UriReferenceEvent(datatype, String.Empty); IUriNode dturi = this.Resolve(context, dtref, element.BaseUri); obj = context.Handler.CreateLiteralNode(text.Value, dturi.Uri); } //Assert the Triple if (!context.Handler.HandleTriple(new Triple(subj, pred, obj))) ParserHelper.Stop(); //Reify if applicable if (!ID.Equals(String.Empty)) { //Resolve the Uri UriReferenceEvent uriref = new UriReferenceEvent(ID, String.Empty); IUriNode uri = this.Resolve(context, uriref,element.BaseUri); this.Reify(context, uri, subj, pred, obj); } }
/// <summary> /// Implementation of the RDF/XML Grammar Production 'nodeElementList' /// </summary> /// <param name="context">Parser Context</param> /// <param name="eventlist">Queue of Events to apply the Production to</param> private void GrammarProductionNodeElementList(RdfXmlParserContext context, IEventQueue<IRdfXmlEvent> eventlist) { //Tracing if (this._traceparsing) { this.ProductionTrace("Node Element List"); } IRdfXmlEvent next; //Want to break up into a number of sublists while (eventlist.Count > 0) { //Create a new Sublist IEventQueue<IRdfXmlEvent> subevents = new EventQueue<IRdfXmlEvent>(); int nesting = 0; //Gather the Sublist taking account of nesting do { next = eventlist.Dequeue(); subevents.Enqueue(next); if (next is ElementEvent) { nesting++; } else if (next is EndElementEvent) { nesting--; } } while (nesting > 0); //Call the next Grammar Production this.GrammarProductionNodeElement(context, subevents); } }
/// <summary> /// Function which does the actual Parsing by invoking the various steps of the Parser /// </summary> /// <param name="context">Parser Context</param> private void Parse(RdfXmlParserContext context) { try { context.Handler.StartRdf(); //Trace Parser Information if (this._traceparsing) { Console.WriteLine("Trace Format is as follows:"); Console.WriteLine("NestingLevel EventType [Description]"); Console.WriteLine(); } //Process the Queue this.ProcessEventQueue(context); context.Handler.EndRdf(true); } catch (RdfParsingTerminatedException) { context.Handler.EndRdf(true); //Discard this - it justs means the Handler told us to stop } catch { context.Handler.EndRdf(false); throw; } }
/// <summary> /// Starts the Parsing of the flattened Event Tree by calling the appropriate Grammar Production based on the type of the First Event in the Queue /// </summary> private void ProcessEventQueue(RdfXmlParserContext context) { //Get First Event IRdfXmlEvent first = context.Events.Dequeue(); bool setBaseUri = (context.BaseUri == null); Uri baseUri; if (first is RootEvent) { this.GrammarProductionDoc(context, (RootEvent)first); if (setBaseUri && !((RootEvent)first).BaseUri.Equals(String.Empty)) { baseUri = UriFactory.Create(Tools.ResolveUri(((RootEvent)first).BaseUri, String.Empty)); context.BaseUri = baseUri; if (!context.Handler.HandleBaseUri(baseUri)) ParserHelper.Stop(); } } else { this.GrammarProductionRDF(context, (ElementEvent)first); if (setBaseUri && !((ElementEvent)first).BaseUri.Equals(String.Empty)) { baseUri = UriFactory.Create(Tools.ResolveUri(((ElementEvent)first).BaseUri, String.Empty)); context.BaseUri = baseUri; if (!context.Handler.HandleBaseUri(baseUri)) ParserHelper.Stop(); } } }
/// <summary> /// Implementation of the RDF/XML Grammar Production 'RDF' /// </summary> /// <param name="context">Parser Context</param> /// <param name="element">RDF Element to apply Production to</param> private void GrammarProductionRDF(RdfXmlParserContext context, ElementEvent element) { //Tracing if (this._traceparsing) { this.ProductionTrace("RDF", element); } //Check Uri is correct String localName = element.LocalName; String prefix = element.Namespace; if (localName.Equals("RDF") || ((context.Namespaces.HasNamespace(prefix) && context.Namespaces.GetNamespaceUri(prefix).ToString().Equals(NamespaceMapper.RDF)) || element.NamespaceAttributes.Any(ns => ns.Prefix.Equals(prefix) && ns.Uri.Equals(NamespaceMapper.RDF)))) { //This is OK } else { throw ParserHelper.Error("Unexpected Node '" + element.QName + "', an 'rdf:RDF' node was expected", "RDF", element); } //Check has no Attributes if (element.Attributes.Count > 0) { throw ParserHelper.Error("Root Node should not contain any attributes other than XML Namespace Declarations", "RDF", element); } //Apply Namespaces this.ApplyNamespaces(context, element); //Build a Sublist of all Nodes up to the matching EndElement IEventQueue<IRdfXmlEvent> subevents = new EventQueue<IRdfXmlEvent>(); IRdfXmlEvent next; //Make sure we discard the current ElementEvent which will be at the front of the queue context.Events.Dequeue(); //Gather the Sublist while (context.Events.Count > 1) { subevents.Enqueue(context.Events.Dequeue()); } //Call the NodeElementList Grammer Production this.GrammarProductionNodeElementList(context, subevents); //Next Event in queue should be an EndElementEvent or we Error next = context.Events.Dequeue(); if (!(next is EndElementEvent)) { throw ParserHelper.Error("Unexpected Event '" + next.GetType().ToString() + "', an EndElementEvent was expected", "RDF", element); } }
/// <summary> /// Implementation of the RDF/XML Grammar Production 'resourcePropertyElt' /// </summary> /// <param name="context">Parser Context</param> /// <param name="eventlist">Queue of Events that make up the Resource Property Element and its Children</param> /// <param name="parent">Parent Event (ie. Node) of the Property Element</param> private void GrammarProductionResourcePropertyElement(RdfXmlParserContext context, IEventQueue<IRdfXmlEvent> eventlist, IRdfXmlEvent parent) { //Tracing if (this._traceparsing) { this.ProductionTracePartial("Resource Property Element"); } //Cast to an ElementEvent //We don't validate type here since we know this will be an ElementEvent because the calling function //will have done this validation previously IRdfXmlEvent first = eventlist.Dequeue(); IRdfXmlEvent next = eventlist.Peek(); ElementEvent element = (ElementEvent)first; if (this._traceparsing) this.ProductionTracePartial(element); //Apply Namespaces this.ApplyNamespaces(context, element); //Only allowed one attribute max which must be an ID attribute String ID = String.Empty; if (element.Attributes.Count > 1) { throw ParserHelper.Error("A Resource Property Element contains too many Attributes, only rdf:ID is permitted", element); } else if (element.Attributes.Count == 1) { if (!RdfXmlSpecsHelper.IsIDAttribute(element.Attributes.First())) { throw ParserHelper.Error("A Resource Property Element was encountered with a single attribute which was not rdf:ID, only rdf:ID is permitted", element); } else { ID = element.Attributes.First().Value; } } //Next must be an ElementEvent if (!(next is ElementEvent)) { throw ParserHelper.Error("Unexpected Event '" + next.GetType().ToString() + "', expected an ElementEvent as the first Event in a Resource Property Elements Event list", next); } //Get list of Sub Events IEventQueue<IRdfXmlEvent> subevents = new EventQueue<IRdfXmlEvent>(); while (eventlist.Count > 1) { subevents.Enqueue(eventlist.Dequeue()); } this.GrammarProductionNodeElement(context, subevents); //Check Last is an EndElementEvent IRdfXmlEvent last = eventlist.Dequeue(); if (!(last is EndElementEvent)) { throw ParserHelper.Error("Unexpected Event '" + last.GetType().ToString() + "', expected an EndElement Event", last); } //Now we can generate the relevant RDF INode subj, pred, obj; //Validate the Type of the Parent if (!(parent is ElementEvent)) { throw ParserHelper.Error("Unexpected Parent Event '" + parent.GetType().ToString() + "', expected an ElementEvent", parent); } ElementEvent parentEl = (ElementEvent)parent; //Get the Subject Node from the Parent subj = parentEl.SubjectNode; //Validate the ID (if any) if (!ID.Equals(String.Empty)) { this.ValidateID(context, ID, subj); } //Create a Predicate from this Element pred = this.Resolve(context, element);//context.Handler.CreateUriNode(element.QName); //Get the Object Node from the Child Node ElementEvent child = (ElementEvent)next; obj = child.SubjectNode; //Assert the Triple if (!context.Handler.HandleTriple(new Triple(subj, pred, obj))) ParserHelper.Stop(); //Add Reification where appropriate if (element.Attributes.Count == 1) { //Must be an rdf:ID attribute as we've validated this earlier //Get the Attribute Event and generate a Uri from it AttributeEvent attr = element.Attributes.First(); UriReferenceEvent uriref = new UriReferenceEvent("#" + attr.Value, attr.SourceXml); IUriNode uri = this.Resolve(context, uriref, element.BaseUri); this.Reify(context, uri, subj, pred, obj); } }
/// <summary> /// Implementation of the RDF/XML Grammar Production 'propertyElt' /// </summary> /// <param name="context">Parser Context</param> /// <param name="eventlist">Queue of Events that make up the Property Element and its Children</param> /// <param name="parent">Parent Event (ie. Node) of the Property Element</param> private void GrammarProductionPropertyElement(RdfXmlParserContext context, IEventQueue<IRdfXmlEvent> eventlist, IRdfXmlEvent parent) { //Tracing if (this._traceparsing) { this.ProductionTracePartial("Property Element"); } //Get first thing from the Queue IRdfXmlEvent first = eventlist.Dequeue(); ElementEvent element; //Must be an ElementEvent if (!(first is ElementEvent)) { //Unexpected Event throw ParserHelper.Error("Expected an ElementEvent but encountered a '" + first.GetType().ToString() + "'", "PropertyElement", first); } //Validate the Uri element = (ElementEvent)first; if (this._traceparsing) this.ProductionTracePartial(element); this.ApplyNamespaces(context, element); if (!RdfXmlSpecsHelper.IsPropertyElementURI(element.QName)) { //Invalid Uri throw ParserHelper.Error("A Property Element was encountered with an invalid URI '" + element.QName + "'\nCore Syntax Terms, Old Syntax Terms and rdf:Description cannot be used as Property Element URIs", "PropertyElement", element); } //List Expansion if (element.QName.Equals("rdf:li")) { UriReferenceEvent u = this.ListExpand(parent); element.SetUri(u); } //Need to select what to do based on the Type of Property Element IRdfXmlEvent next = eventlist.Peek(); //This call inserts the first element back at the head of the queue //Most of the sub-productions here need this //Would ideally use Stacks instead of Queues but Queues make more sense for most of the Parsing this.QueueJump(eventlist, first); if (element.ParseType == RdfXmlParseType.None) { //A Resource/Literal Property Element if (next is ElementEvent) { //Resource this.GrammarProductionResourcePropertyElement(context, eventlist, parent); } else if (next is TextEvent) { //Literal this.GrammarProductionLiteralPropertyElement(context, eventlist, parent); } else if (next is EndElementEvent) { //An Empty Property Element this.GrammarProductionEmptyPropertyElement(context, element, parent); } else { //Error throw ParserHelper.Error("An Element which should be Parsed with the Default Parsing Rules was encountered without a valid subsequent Event - Parser cannot proceed!", "Property Element", element); } } else if (element.ParseType == RdfXmlParseType.Literal) { //A rdf:parseType="Literal" Property Element this.GrammarProductionParseTypeLiteralPropertyElement(context, eventlist, parent); } else if (element.ParseType == RdfXmlParseType.Collection) { //A rdf:parseType="Collection" Property Element this.GrammarProductionParseTypeCollectionPropertyElement(context, eventlist, parent); } else if (element.ParseType == RdfXmlParseType.Resource) { //A rdf:parseType="Resource" Property Element this.GrammarProductionParseTypeResourcePropertyElement(context, eventlist, parent); } else if (next is EndElementEvent) { //An Empty Property Element this.GrammarProductionEmptyPropertyElement(context, element, parent); } else { //Error throw ParserHelper.Error("An Element without a known Parse Type was encountered Or the Parser was unable to determine what to do based on the subsequent event - Parser cannot proceed!", "Node Element", element); } }
/// <summary> /// Implementation of the RDF/XML Grammar Production 'parseTypeResourcePropertyElt' /// </summary> /// <param name="context">Parser Context</param> /// <param name="eventlist">Queue of Events that make up the Resource Parse Type Property Element and its Children</param> /// <param name="parent">Parent Event (ie. Node) of the Property Element</param> private void GrammarProductionParseTypeResourcePropertyElement(RdfXmlParserContext context, IEventQueue<IRdfXmlEvent> eventlist, IRdfXmlEvent parent) { //Tracing if (this._traceparsing) { this.ProductionTracePartial("Parse Type Resource Property Element"); } //Get the first Event, should be an ElementEvent //Type checking is done by the Parent Production IRdfXmlEvent first = eventlist.Dequeue(); ElementEvent element = (ElementEvent)first; if (this._traceparsing) this.ProductionTracePartial(element); //Apply Namespaces this.ApplyNamespaces(context, element); //Validate Attributes String ID = String.Empty; if (element.Attributes.Count > 2) { //Can't be more than 2 Attributes, only allowed an optional rdf:ID and a required rdf:parseType throw ParserHelper.Error("An Property Element with Parse Type 'Resource' was encountered with too many Attributes. Only rdf:ID and rdf:parseType are allowed on Property Elements with Parse Type 'Resource'", "Parse Type Resource Property Element", element); } else { //Check the attributes that do exist foreach (AttributeEvent a in element.Attributes) { if (RdfXmlSpecsHelper.IsIDAttribute(a)) { ID = "#" + a.Value; } else if (a.QName.Equals("rdf:parseType")) { //OK } else { //Invalid Attribute throw ParserHelper.Error("Unexpected Attribute '" + a.QName + "' was encountered on a Property Element with Parse Type 'Resource'. Only rdf:ID and rdf:parseType are allowed on Property Elements with Parse Type 'Resource'", "Parse Type Resource Property Element", element); } } } //Add a Triple about this INode subj, pred, obj; //Get the Subject from the Parent ElementEvent parentEvent = (ElementEvent)parent; subj = parentEvent.SubjectNode; //Validate the ID (if any) if (!ID.Equals(String.Empty)) { this.ValidateID(context, ID.Substring(1), subj); } //Create the Predicate from the Element pred = this.Resolve(context, element);//context.Handler.CreateUriNode(element.QName); //Generate a Blank Node ID for the Object obj = context.Handler.CreateBlankNode(); //Assert if (!context.Handler.HandleTriple(new Triple(subj, pred, obj))) ParserHelper.Stop(); //Reify if applicable if (!ID.Equals(String.Empty)) { //Resolve the Uri UriReferenceEvent uriref = new UriReferenceEvent(ID, String.Empty); IUriNode uri = this.Resolve(context, uriref,element.BaseUri); this.Reify(context, uri, subj, pred, obj); } //Get the next event in the Queue which should be either an Element Event or a End Element Event //Validate this IRdfXmlEvent next = eventlist.Dequeue(); if (next is EndElementEvent) { //Content is Empty so nothing else to do } else if (next is ElementEvent) { //Non-Empty Content so need to build a sequence of new events IEventQueue<IRdfXmlEvent> subEvents = new EventQueue<IRdfXmlEvent>(); //Create an rdf:Description event as the container ElementEvent descrip = new ElementEvent("rdf:Description", element.BaseUri, String.Empty); descrip.Subject = new BlankNodeIDEvent(String.Empty); descrip.SubjectNode = obj; subEvents.Enqueue(descrip); //Add the current element we were looking at subEvents.Enqueue(next); //Add rest of events in list (exceot the last) while (eventlist.Count > 1) { subEvents.Enqueue(eventlist.Dequeue()); } //Terminate with an EndElement Event subEvents.Enqueue(new EndElementEvent()); //Process with Node Element Production this.GrammarProductionNodeElement(context, subEvents); //Get the last thing in the List next = eventlist.Dequeue(); } else { throw ParserHelper.Error("Unexpected Event '" + next.GetType().ToString() + "', expected an ElementEvent or EndElementEvent after a Parse Type Resource Property Element!", "Parse Type Resource Property Element", next); } //Check for the last thing being an EndElement Event if (!(next is EndElementEvent)) { throw ParserHelper.Error("Unexpected Event '" + next.GetType().ToString() + "', expected an EndElementEvent to terminate a Parse Type Resource Property Element!", "Parse Type Resource Property Element", next); } }
/// <summary> /// Implementation of the RDF/XML Grammar Production 'parseTypeLiteralPropertyElt' /// </summary> /// <param name="context">Parser Context</param> /// <param name="eventlist">Queue of Events that make up the Literal Parse Type Property Element and its Children</param> /// <param name="parent">Parent Event (ie. Node) of the Property Element</param> private void GrammarProductionParseTypeLiteralPropertyElement(RdfXmlParserContext context, IEventQueue<IRdfXmlEvent> eventlist, IRdfXmlEvent parent) { //Tracing if (this._traceparsing) { this.ProductionTracePartial("Parse Type Literal Property Element"); } //Get the first Event, should be an ElementEvent //Type checking is done by the Parent Production IRdfXmlEvent first = eventlist.Dequeue(); ElementEvent element = (ElementEvent)first; if (this._traceparsing) this.ProductionTracePartial(element); //Apply Namespaces this.ApplyNamespaces(context, element); //Validate Attributes String ID = String.Empty; if (element.Attributes.Count > 2) { //Can't be more than 2 Attributes, only allowed an optional rdf:ID and a required rdf:parseType throw ParserHelper.Error("An Property Element with Parse Type 'Literal' was encountered with too many Attributes. Only rdf:ID and rdf:parseType are allowed on Property Elements with Parse Type 'Literal'", "Parse Type Literal Property Element", element); } else { //Check the attributes that do exist foreach (AttributeEvent a in element.Attributes) { if (RdfXmlSpecsHelper.IsIDAttribute(a)) { ID = "#" + a.Value; } else if (a.QName.Equals("rdf:parseType")) { //OK } else { //Invalid Attribute throw ParserHelper.Error("Unexpected Attribute '" + a.QName + "' was encountered on a Property Element with Parse Type 'Literal'. Only rdf:ID and rdf:parseType are allowed on Property Elements with Parse Type 'Literal'", "Parse Type Literal Property Element", element); } } } //Get the next event in the Queue which should be a TypedLiteralEvent //Validate this IRdfXmlEvent lit = eventlist.Dequeue(); if (!(lit is TypedLiteralEvent)) { throw ParserHelper.Error("Unexpected Event '" + lit.GetType().ToString() + "', expected a TypedLiteralEvent after a Property Element with Parse Type 'Literal'", "Parse Type Literal Property Element", lit); } //Get the Subject from the Parent INode subj, pred, obj; ElementEvent parentEl = (ElementEvent) parent; subj = parentEl.SubjectNode; //Validate the ID (if any) if (!ID.Equals(String.Empty)) { this.ValidateID(context, ID.Substring(1), subj); } //Create the Predicate from the Element pred = this.Resolve(context, element);//context.Handler.CreateUriNode(element.QName); //Create the Object from the Typed Literal TypedLiteralEvent tlit = (TypedLiteralEvent)lit; //At the moment we're just going to ensure that we normalize it to Unicode Normal Form C String xmllit = tlit.Value; #if !NO_NORM xmllit = xmllit.Normalize(); #endif obj = context.Handler.CreateLiteralNode(xmllit, UriFactory.Create(tlit.DataType)); //Assert the Triple if (!context.Handler.HandleTriple(new Triple(subj, pred, obj))) ParserHelper.Stop(); //Reify if applicable if (!ID.Equals(String.Empty)) { //Resolve the Uri UriReferenceEvent uriref = new UriReferenceEvent(ID, String.Empty); IUriNode uri = this.Resolve(context, uriref,element.BaseUri); this.Reify(context, uri, subj, pred, obj); } //Check for the last thing being an EndElement Event IRdfXmlEvent next = eventlist.Dequeue(); if (!(next is EndElementEvent)) { throw ParserHelper.Error("Unexpected Event '" + next.GetType().ToString() + "', expected an EndElementEvent to terminate a Parse Type Literal Property Element!", "Parse Type Literal Property Element", next); } }
/// <summary> /// Implementation of the RDF/XML Grammar Production 'doc' /// </summary> /// <param name="context">Parser Context</param> /// <param name="root">Root Event to start applying Productions from</param> private void GrammarProductionDoc(RdfXmlParserContext context, RootEvent root) { //Tracing if (this._traceparsing) { this.ProductionTrace("Doc"); } //Call the RDF Production on the first child if it's an rdf:RDF element //if (root.Children[0].QName.Equals("rdf:RDF") || root.Children[0].QName.Equals(":RDF")) String localName = root.Children[0].LocalName; String prefix = root.Children[0].Namespace; if (localName.Equals("RDF") && ((context.Namespaces.HasNamespace(prefix) && context.Namespaces.GetNamespaceUri(prefix).ToString().Equals(NamespaceMapper.RDF)) || root.DocumentElement.NamespaceAttributes.Any(ns => ns.Prefix.Equals(prefix) && ns.Uri.Equals(NamespaceMapper.RDF)))) { this.GrammarProductionRDF(context, root.Children[0]); } else { //No rdf:RDF element //Drop first element from Queue (which will be a RootEvent) //Skip straight to NodeElementList production //context.Events.Dequeue(); this.GrammarProductionNodeElementList(context, context.Events); } }
/// <summary> /// Reifies a Triple /// </summary> /// <param name="context">Parser Context</param> /// <param name="uriref">Uri Reference for the Reified Triple</param> /// <param name="subj">Subject of the Triple</param> /// <param name="pred">Predicate of the Triple</param> /// <param name="obj">Object of the Triple</param> private void Reify(RdfXmlParserContext context, IUriNode uriref, INode subj, INode pred, INode obj) { if (!context.Handler.HandleTriple(new Triple(uriref, context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfSubject)), subj))) ParserHelper.Stop(); if (!context.Handler.HandleTriple(new Triple(uriref, context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfPredicate)), pred))) ParserHelper.Stop(); if (!context.Handler.HandleTriple(new Triple(uriref, context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfObject)), obj))) ParserHelper.Stop(); if (!context.Handler.HandleTriple(new Triple(uriref, context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfType)), context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfStatement))))) ParserHelper.Stop(); }
/// <summary> /// Implementation of the RDF/XML Grammar Production 'emptyPropertyElt' /// </summary> /// <param name="context">Parser Context</param> /// <param name="element">Element Event for the Empty Property Element</param> /// <param name="parent">Parent Event (ie. Node) of the Property Element</param> private void GrammarProductionEmptyPropertyElement(RdfXmlParserContext context, ElementEvent element, IRdfXmlEvent parent) { //Tracing if (this._traceparsing) { this.ProductionTrace("Empty Property Element"); } //Apply Namespaces this.ApplyNamespaces(context, element); INode subj, pred, obj; ElementEvent parentEl; //Are there any attributes OR Only a rdf:ID attribute? if (element.Attributes.Count == 0 || (element.Attributes.Count == 1 && RdfXmlSpecsHelper.IsIDAttribute(element.Attributes[0]))) { //No Attributes/Only rdf:ID //Get the Subject Node from the Parent parentEl = (ElementEvent)parent; subj = parentEl.SubjectNode; //Create the Predicate from the Element pred = this.Resolve(context, element);//context.Handler.CreateUriNode(element.QName); //Create the Object if (!element.Language.Equals(String.Empty)) { obj = context.Handler.CreateLiteralNode(String.Empty, element.Language); } else { obj = context.Handler.CreateLiteralNode(String.Empty); } //Make the Assertion if (!context.Handler.HandleTriple(new Triple(subj, pred, obj))) ParserHelper.Stop(); //Reifiy if applicable if (element.Attributes.Count == 1) { //Validate the ID this.ValidateID(context, element.Attributes[0].Value, subj); //Resolve the Uri UriReferenceEvent uriref = new UriReferenceEvent("#" + element.Attributes[0].Value, String.Empty); IUriNode uri = this.Resolve(context, uriref, element.BaseUri); this.Reify(context, uri, subj, pred, obj); } } else if (element.Attributes.Count > 0 && element.Attributes.Where(a => RdfXmlSpecsHelper.IsDataTypeAttribute(a)).Count() == 1) { //Should be processed as a Typed Literal Event instead EventQueue<IRdfXmlEvent> temp = new EventQueue<IRdfXmlEvent>(); temp.Enqueue(element); temp.Enqueue(new TextEvent(String.Empty, String.Empty)); temp.Enqueue(new EndElementEvent()); this.GrammarProductionLiteralPropertyElement(context, temp, parent); return; } else { //Check through attributes IRdfXmlEvent res = null; //Check through attributes to decide the Subject of the Triple(s) String ID = String.Empty; int limitedAttributes = 0; foreach (AttributeEvent a in element.Attributes) { if (RdfXmlSpecsHelper.IsResourceAttribute(a)) { //An rdf:resource attribute so a Uri Reference res = new UriReferenceEvent(a.Value, a.SourceXml); limitedAttributes++; } else if (RdfXmlSpecsHelper.IsNodeIDAttribute(a)) { //An rdf:nodeID attribute so a Blank Node //Validate the Node ID if (!XmlSpecsHelper.IsName(a.Value)) { //Invalid nodeID throw ParserHelper.Error("The value '" + a.Value + "' for rdf:nodeID is not valid, RDF Node IDs can only be valid Names as defined by the W3C XML Specification", "Empty Property Element", a); } res = new BlankNodeIDEvent(a.Value, a.SourceXml); limitedAttributes++; } else if (RdfXmlSpecsHelper.IsIDAttribute(a)) { //Set the ID for later use in reification ID = "#" + a.Value; } //Check we haven't got more than 1 of the Limited Attributes if (limitedAttributes > 1) { throw ParserHelper.Error("A Property Element can only have 1 of the following attributes: rdf:nodeID or rdf:resource", "Empty Property Element", element); } } if (res == null) { //No relevant attributes so an anonymous Blank Node res = new BlankNodeIDEvent(String.Empty); } //Now create the actual Subject Node if (res is UriReferenceEvent) { //Resolve the Uri Reference UriReferenceEvent uriref = (UriReferenceEvent)res; subj = this.Resolve(context, uriref, element.BaseUri); } else if (res is BlankNodeIDEvent) { BlankNodeIDEvent blank = (BlankNodeIDEvent)res; if (blank.Identifier.Equals(String.Empty)) { //Have the Graph generate a Blank Node ID subj = context.Handler.CreateBlankNode(); } else { //Use the supplied Blank Node ID subj = context.Handler.CreateBlankNode(blank.Identifier); } } else { //Should never hit this case but required to get the Code to Compile //Have the Graph generate a Blank Node ID subj = context.Handler.CreateBlankNode(); } //Validate the ID (if any) if (!ID.Equals(String.Empty)) { this.ValidateID(context, ID.Substring(1), subj); } //Relate the Property element to its parent parentEl = (ElementEvent)parent; pred = this.Resolve(context, element);//context.Handler.CreateUriNode(element.QName); if (!context.Handler.HandleTriple(new Triple(parentEl.SubjectNode, pred, subj))) ParserHelper.Stop(); //Reify if applicable if (!ID.Equals(String.Empty)) { //Resolve the Uri UriReferenceEvent uriref = new UriReferenceEvent(ID, String.Empty); IUriNode uri = this.Resolve(context, uriref, element.BaseUri); this.Reify(context, uri, parentEl.SubjectNode, pred, subj); } //Process the rest of the Attributes foreach (AttributeEvent a in element.Attributes) { if (a.QName.Equals("rdf:type")) { //A Property Attribute giving a Type //Assert a Type Triple UriReferenceEvent type = new UriReferenceEvent(a.Value, a.SourceXml); pred = context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfType)); obj = this.Resolve(context, type, element.BaseUri); if (!context.Handler.HandleTriple(new Triple(parentEl.SubjectNode, pred, obj))) ParserHelper.Stop(); } else if (RdfXmlSpecsHelper.IsPropertyAttribute(a)) { //A Property Attribute //Validate the Normalization of the Attribute Value #if !NO_NORM if (!a.Value.IsNormalized()) { throw ParserHelper.Error("Encountered a Property Attribute '" + a.QName + "' whose value was not correctly normalized in Unicode Normal Form C", "Empty Property Element", a); } else { #endif //Create the Predicate from the Attribute QName pred = context.Handler.CreateUriNode(UriFactory.Create(Tools.ResolveQName(a.QName, context.Namespaces, context.BaseUri))); //Create the Object from the Attribute Value if (element.Language.Equals(String.Empty)) { obj = context.Handler.CreateLiteralNode(a.Value); } else { obj = context.Handler.CreateLiteralNode(a.Value, element.Language); } //Assert the Property Triple if (!context.Handler.HandleTriple(new Triple(subj, pred, obj))) ParserHelper.Stop(); #if !NO_NORM } #endif } else if (RdfXmlSpecsHelper.IsIDAttribute(a) || RdfXmlSpecsHelper.IsNodeIDAttribute(a) || RdfXmlSpecsHelper.IsResourceAttribute(a)) { //These have already been processed //We test for them so that we can then throw ParserHelper.Errors in the final case for unexpected attributes } else { //Unexpected Attribute throw ParserHelper.Error("Unexpected Attribute '" + a.QName + "' encountered on a Property Element! Only rdf:ID, rdf:resource, rdf:nodeID and Property Attributes are permitted on Property Elements", "Empty Property Element", element); } } } }
/// <summary> /// Resolves a Uri Reference into a Uri Node against a given Base Uri /// </summary> /// <param name="context">Parser Context</param> /// <param name="uriref">Uri Reference to Resolve</param> /// <param name="baseUri">Base Uri to Resolve against</param> /// <returns></returns> private IUriNode Resolve(RdfXmlParserContext context, UriReferenceEvent uriref, String baseUri) { try { if (baseUri.Equals(String.Empty)) baseUri = context.BaseUri.ToSafeString(); IUriNode u = context.Handler.CreateUriNode(UriFactory.Create(Tools.ResolveUri(uriref.Identifier, baseUri))); return u; } catch (Exception ex) { //Catch the error so we can wrap in in our own error function //If it fails then we know we got an error caused by this Event throw ParserHelper.Error(ex.Message, uriref); } }
/// <summary> /// Implementation of the RDF/XML Grammar Production 'nodeElement' /// </summary> /// <param name="context">Parser Context</param> /// <param name="eventlist">Queue of Events that make up the Node Element and its Children to apply the Production to</param> private void GrammarProductionNodeElement(RdfXmlParserContext context, IEventQueue<IRdfXmlEvent> eventlist) { //Tracing if (this._traceparsing) { this.ProductionTracePartial("Node Element"); } //Get First Event in the Queue IRdfXmlEvent first = eventlist.Dequeue(); //Check it's an ElementEvent if (!(first is ElementEvent)) { //Unexpected Event throw ParserHelper.Error("Expected an ElementEvent but encountered a '" + first.GetType().ToString() + "'", "Node Element", first); } //Check it has a valid Uri ElementEvent element = (ElementEvent)first; if (this._traceparsing) this.ProductionTracePartial(element); this.ApplyNamespaces(context, element); if (!RdfXmlSpecsHelper.IsNodeElementUri(element.QName)) { throw ParserHelper.Error("A Node Element was encountered with an invalid URI '" + element.QName + "' \nCore Syntax Terms, Old Syntax Terms and rdf:li cannot be used as Node Element URIs", "Node Element", element); } //Check the set of Attributes is Valid int limitedAttributesFound = 0; String ID = String.Empty; foreach (AttributeEvent attr in element.Attributes) { if (RdfXmlSpecsHelper.IsIDAttribute(attr)) { ID = attr.Value; limitedAttributesFound++; //Set the Subject element.Subject = new UriReferenceEvent("#" + attr.Value, attr.SourceXml); } else if (RdfXmlSpecsHelper.IsNodeIDAttribute(attr)) { limitedAttributesFound++; //Validate the Node ID if (!XmlSpecsHelper.IsName(attr.Value)) { throw ParserHelper.Error("The value '" + attr.Value + "' for rdf:nodeID is not valid, RDF Node IDs can only be valid Names as defined by the W3C XML Specification", "Node Element", attr); } //Set the Subject element.Subject = new BlankNodeIDEvent(attr.Value, attr.SourceXml); } else if (RdfXmlSpecsHelper.IsAboutAttribute(attr)) { limitedAttributesFound++; //Set the Subject element.Subject = new UriReferenceEvent(attr.Value, attr.SourceXml); } else if (RdfXmlSpecsHelper.IsPropertyAttribute(attr)) { //Don't need to do anything here yet } else { //Unknown and Unexpected Attribute Type throw ParserHelper.Error("Unexpected Attribute '" + attr.QName + "' was encountered!", "Node Element", element); } //Can't have more than 1 of ID, Node ID or About Attributes if (limitedAttributesFound > 1) { throw ParserHelper.Error("A Node Element can only have 1 of the following attributes: rdf:id, rdf:nodeID, rdf:about", "Node Element", element); } } //Generate a Blank Node ID if our Subject is empty if (element.Subject == null) { element.Subject = new BlankNodeIDEvent(element.SourceXml); } //Add statements as necessary INode subj, pred, obj; if (element.SubjectNode == null) { //Don't always want to drop in here since the SubjectNode may already be set elsewhere if (element.Subject is UriReferenceEvent) { UriReferenceEvent uri = (UriReferenceEvent)element.Subject; subj = this.Resolve(context, uri, element.BaseUri); } else if (element.Subject is BlankNodeIDEvent) { BlankNodeIDEvent blank = (BlankNodeIDEvent)element.Subject; //Select whether we need to generate an ID or if there's one given for the Blank Node //Note that we let the Graph class handle generation of IDs if (blank.Identifier.Equals(String.Empty)) { subj = context.Handler.CreateBlankNode(); } else { subj = context.Handler.CreateBlankNode(blank.Identifier); } } else { throw ParserHelper.Error("Unexpected Subject generated for a Triple", "Node Element", element.Subject); } } else { subj = element.SubjectNode; } //Set the Subject Node property of the Event for later reuse element.SubjectNode = subj; //Validate the ID (if any) if (!ID.Equals(String.Empty)) { this.ValidateID(context, ID, subj); } if (!element.QName.Equals("rdf:Description") && !element.QName.Equals(":Description")) { //Assert a Triple regarding Type pred = context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfType)); obj = this.Resolve(context, element);//context.Handler.CreateUriNode(element.QName); if (!context.Handler.HandleTriple(new Triple(subj, pred, obj))) ParserHelper.Stop(); } //Go back over Attributes looking for property attributes foreach (AttributeEvent attr in element.Attributes) { if (RdfXmlSpecsHelper.IsPropertyAttribute(attr)) { if (attr.QName.Equals("rdf:type")) { //Generate a Type Triple pred = context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfType)); //Resolve URIRef into a Uri Node UriReferenceEvent uriref = new UriReferenceEvent(attr.Value, attr.SourceXml); obj = this.Resolve(context, uriref, element.BaseUri); if (!context.Handler.HandleTriple(new Triple(subj, pred, obj))) ParserHelper.Stop(); } else { //Generate a Property Triple pred = context.Handler.CreateUriNode(UriFactory.Create(Tools.ResolveQName(attr.QName, context.Namespaces, context.BaseUri))); //Add Language to Literal if necessary if (element.Language.Equals(String.Empty)) { obj = context.Handler.CreateLiteralNode(attr.Value); } else { obj = context.Handler.CreateLiteralNode(attr.Value, element.Language); } if (!context.Handler.HandleTriple(new Triple(subj, pred, obj))) ParserHelper.Stop(); } } } //Handle Child Elements IEventQueue<IRdfXmlEvent> children = new EventQueue<IRdfXmlEvent>(); while (eventlist.Count > 1) { children.Enqueue(eventlist.Dequeue()); } if (children.Count > 0) this.GrammarProductionPropertyElementList(context, children, element); //Check Last Event in queue is an EndElement event IRdfXmlEvent last = eventlist.Dequeue(); if (!(last is EndElementEvent)) { throw ParserHelper.Error("Unexpected Event '" + last.GetType().ToString() + "', expected an EndElement Event", "NodeElement", last); } }
private IUriNode Resolve(RdfXmlParserContext context, ElementEvent el) { try { IUriNode u = context.Handler.CreateUriNode(UriFactory.Create(Tools.ResolveQName(el.QName, context.Namespaces, context.BaseUri))); return u; } catch (Exception ex) { throw ParserHelper.Error(ex.Message, el); } }
/// <summary> /// Implementation of the RDF/XML Grammar Production 'parseTypeCollectionPropertyElt' /// </summary> /// <param name="context">Parser Context</param> /// <param name="eventlist">Queue of Events that make up the Collection Parse Type Property Element and its Children</param> /// <param name="parent">Parent Event (ie. Node) of the Property Element</param> private void GrammarProductionParseTypeCollectionPropertyElement(RdfXmlParserContext context, IEventQueue<IRdfXmlEvent> eventlist, IRdfXmlEvent parent) { //Tracing if (this._traceparsing) { this.ProductionTracePartial("Parse Type Collection Property Element"); } //Get the first Event, should be an ElementEvent //Type checking is done by the Parent Production IRdfXmlEvent first = eventlist.Dequeue(); ElementEvent element = (ElementEvent)first; if (this._traceparsing) this.ProductionTracePartial(element); //Apply Namespaces this.ApplyNamespaces(context, element); //Validate Attributes String ID = String.Empty; if (element.Attributes.Count > 2) { //Can't be more than 2 Attributes, only allowed an optional rdf:ID and a required rdf:parseType throw ParserHelper.Error("An Property Element with Parse Type 'Collection' was encountered with too many Attributes. Only rdf:ID and rdf:parseType are allowed on Property Elements with Parse Type 'Collection'", "Parse Type Collection Property Element", element); } else { //Check the attributes that do exist foreach (AttributeEvent a in element.Attributes) { if (RdfXmlSpecsHelper.IsIDAttribute(a)) { ID = "#" + a.Value; } else if (a.QName.Equals("rdf:parseType")) { //OK } else { //Invalid Attribute throw ParserHelper.Error("Unexpected Attribute '" + a.QName + "' was encountered on a Property Element with Parse Type 'Collection'. Only rdf:ID and rdf:parseType are allowed on Property Elements with Parse Type 'Collection'", "Parse Type Collection Property Element", element); } } } //Build sequence of Blank Nodes IRdfXmlEvent next; IRdfXmlEvent nodeElement; Queue<ElementEvent> seqNodes = new Queue<ElementEvent>(); while (eventlist.Count > 1) { #region Node Element Processing //Need to process the Node Element first //Create a new Sublist IEventQueue<IRdfXmlEvent> subevents = new EventQueue<IRdfXmlEvent>(); int nesting = 0; nodeElement = eventlist.Peek(); //Add Node Element to sequence seqNodes.Enqueue((ElementEvent)nodeElement); //Gather the Sublist taking account of nesting do { next = eventlist.Dequeue(); subevents.Enqueue(next); if (next is ElementEvent) { nesting++; } else if (next is EndElementEvent) { nesting--; } } while (nesting > 0); //Call the next Grammar Production this.GrammarProductionNodeElement(context, subevents); #endregion } //Build a triple expressing the start of the list (which may be an empty list) INode subj, pred, obj; INode firstPred, restPred; INode b1, b2; //Subject comes from Parent ElementEvent parentElement = (ElementEvent)parent; subj = parentElement.SubjectNode; //Validate the ID (if any) if (!ID.Equals(String.Empty)) { this.ValidateID(context, ID.Substring(1), subj); } //Predicate from the Element pred = this.Resolve(context, element);//context.Handler.CreateUriNode(element.QName); if (seqNodes.Count > 0) { //Non-empty list ElementEvent node; //Get first Element from the Queue node = seqNodes.Dequeue(); //Object is first thing in the Sequence which we create a Blank Node for b1 = context.Handler.CreateBlankNode(); //Assert if (!context.Handler.HandleTriple(new Triple(subj, pred, b1))) ParserHelper.Stop(); //Reify if applicable if (!ID.Equals(String.Empty)) { //Resolve the Uri UriReferenceEvent uriref = new UriReferenceEvent(ID, String.Empty); IUriNode uri = this.Resolve(context, uriref, element.BaseUri); this.Reify(context, uri, subj, pred, b1); } //Set the first element in the list subj = b1; firstPred = context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfListFirst)); if (!context.Handler.HandleTriple(new Triple(subj, firstPred, node.SubjectNode))) ParserHelper.Stop(); //Middle elements of the list restPred = context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfListRest)); while (seqNodes.Count >= 1) { node = seqNodes.Dequeue(); //Set Node 2 to be the rest of the previous items list b2 = context.Handler.CreateBlankNode(); if (!context.Handler.HandleTriple(new Triple(b1, restPred, b2))) ParserHelper.Stop(); //Set Node 2 to be the start of it's own list if (!context.Handler.HandleTriple(new Triple(b2, firstPred, node.SubjectNode))) ParserHelper.Stop(); b1 = b2; } //Set last element of the list to have its rest as nil if (!context.Handler.HandleTriple(new Triple(b1, restPred, context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfListNil))))) ParserHelper.Stop(); } else { //Empty list //Object is therefore rdf:nil obj = context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfListNil)); //Assert if (!context.Handler.HandleTriple(new Triple(subj, pred, obj))) ParserHelper.Stop(); //Reify if applicable if (!ID.Equals(String.Empty)) { //Resolve the Uri UriReferenceEvent uriref = new UriReferenceEvent(ID, String.Empty); IUriNode uri = this.Resolve(context, uriref, element.BaseUri); this.Reify(context, uri, subj, pred, obj); } } //Check last event is an EndElementEvent next = eventlist.Dequeue(); if (!(next is EndElementEvent)) { throw ParserHelper.Error("Unexpected Event '" + next.GetType().ToString() + "', expected an EndElementEvent to terminate a Parse Type Collection Property Element!", "Parse Type Collection Property Element", next); } }
/// <summary> /// Validates that an ID is correctly formed and has only been used once in the context of a given Subject /// </summary> /// <param name="context">Parser Context</param> /// <param name="id">ID to Validate</param> /// <param name="subj">Subject that the ID pertains to</param> private void ValidateID(RdfXmlParserContext context, String id, INode subj) { //Validate the actual ID value if (!XmlSpecsHelper.IsName(id)) { throw new RdfParseException("The value '" + id + "' for rdf:ID is not valid, RDF IDs can only be valid Names as defined by the W3C XML Specification"); } //Validate that the ID hasn't been used more than once in the same Base Uri context if (context.IDs.ContainsKey(id)) { if (context.IDs[id].Contains(subj)) { throw new RdfParseException("An rdf:ID must be unique to a Node within a File, the rdf:ID '" + id + "' has already been used for a Node in this RDF/XML File!"); } else { context.IDs[id].Add(subj); } } else { context.IDs.Add(id, new List<INode>() { subj }); } }
/// <summary> /// Given an XML Node creates the relevant RDF/XML Events for it and recurses as necessary /// </summary> /// <param name="context">Parser Context</param> /// <param name="node">The Node to create Event(s) from</param> /// <param name="parent">The Parent Node of the given Node</param> /// <returns></returns> private ElementEvent GenerateEvents(RdfXmlParserContext context, XmlNode node, IRdfXmlEvent parent) { //Get the Base Uri String baseUri = String.Empty; if (parent is ElementEvent) { baseUri = ((ElementEvent)parent).BaseUri; } //Create an ElementEvent for the Node ElementEvent element = new ElementEvent(node.LocalName, node.Prefix, baseUri, node.OuterXml); //Set the initial Language from the Parent ElementEvent parentEl = (ElementEvent)parent; element.Language = parentEl.Language; #region Attribute Processing //Iterate over Attributes bool parseTypeLiteral = false; foreach (XmlAttribute attr in node.Attributes) { //Watch out for special attributes if (attr.Name == "xml:lang") { //Set Language element.Language = attr.Value; } else if (attr.Name == "xml:base") { //Set Base Uri if (RdfXmlSpecsHelper.IsAbsoluteURI(attr.Value)) { //Absolute Uri element.BaseUri = attr.Value; } else if (!element.BaseUri.Equals(String.Empty)) { //Relative Uri with a Base Uri to resolve against //element.BaseUri += attr.Value; element.BaseUri = Tools.ResolveUri(attr.Value, element.BaseUri); } else { //Relative Uri with no Base Uri throw new RdfParseException("Cannot resolve a Relative Base URI since there is no in-scope Base URI"); } } else if (attr.Prefix == "xmlns") { //Register a Namespace String uri; if (attr.Value.StartsWith("http://")) { //Absolute Uri uri = attr.Value; } else if (!element.BaseUri.Equals(String.Empty)) { //Relative Uri with a Base Uri to resolve against //uri = element.BaseUri + attr.Value; uri = Tools.ResolveUri(attr.Value, element.BaseUri); } else { //Relative Uri with no Base Uri throw new RdfParseException("Cannot resolve a Relative Namespace URI since there is no in-scope Base URI"); } NamespaceAttributeEvent ns = new NamespaceAttributeEvent(attr.LocalName, uri, attr.OuterXml); element.NamespaceAttributes.Add(ns); } else if (attr.Prefix == String.Empty && attr.Name == "xmlns") { //Register a Default Namespace (Empty Prefix) String uri; if (attr.Value.StartsWith("http://")) { //Absolute Uri uri = attr.Value; } else if (!element.BaseUri.Equals(String.Empty)) { //Relative Uri with a Base Uri to resolve against //uri = element.BaseUri + attr.Value; uri = Tools.ResolveUri(attr.Value, element.BaseUri); } else { //Relative Uri with no Base Uri throw new RdfParseException("Cannot resolve a Relative Namespace URI since there is no in-scope Base URI"); } NamespaceAttributeEvent ns = new NamespaceAttributeEvent(String.Empty, uri, attr.OuterXml); element.NamespaceAttributes.Add(ns); } else if (attr.Prefix == "xml" || (attr.Prefix == String.Empty && attr.LocalName.StartsWith("xml"))) { //Ignore other Reserved XML Names } else if (attr.Name == "rdf:parseType" && attr.Value == "Literal") { //Literal Parse Type parseTypeLiteral = true; //Create the Attribute AttributeEvent attrEvent = new AttributeEvent(attr.LocalName, attr.Prefix, attr.Value, attr.OuterXml); element.Attributes.Add(attrEvent); //Set ParseType property correctly element.ParseType = RdfXmlParseType.Literal; } else if (attr.Name == "rdf:parseType") { //Some other Parse Type //Create the Attribute AttributeEvent attrEvent = new AttributeEvent(attr.LocalName, attr.Prefix, attr.Value, attr.OuterXml); element.Attributes.Add(attrEvent); //Set the ParseType property correctly if (attr.Value == "Resource") { element.ParseType = RdfXmlParseType.Resource; } else if (attr.Value == "Collection") { element.ParseType = RdfXmlParseType.Collection; } else { //Have to assume Literal element.ParseType = RdfXmlParseType.Literal; parseTypeLiteral = true; //Replace the Parse Type attribute with one saying it is Literal element.Attributes.Remove(attrEvent); attrEvent = new AttributeEvent(attr.LocalName, attr.Prefix, "Literal", attr.OuterXml); } } else { //Normal Attribute which we generate an Event from AttributeEvent attrEvent = new AttributeEvent(attr.LocalName, attr.Prefix, attr.Value, attr.OuterXml); element.Attributes.Add(attrEvent); } } //Validate generated Attributes for Namespace Confusion and URIRef encoding foreach (AttributeEvent a in element.Attributes) { //Namespace Confusion should only apply to Attributes without a Namespace specified if (a.Namespace.Equals(String.Empty)) { if (RdfXmlSpecsHelper.IsAmbigiousAttributeName(a.LocalName)) { //Can't use any of the RDF terms that mandate the rdf: prefix without it throw ParserHelper.Error("An Attribute with an ambigious name '" + a.LocalName + "' was encountered. The following attribute names MUST have the rdf: prefix - about, aboutEach, ID, bagID, type, resource, parseType", element); } } //URIRef encoding check if (!RdfXmlSpecsHelper.IsValidUriRefEncoding(a.Value)) { throw ParserHelper.Error("An Attribute with an incorrectly encoded URIRef was encountered, URIRef's must be encoded in Unicode Normal Form C", a); } } #endregion //Don't proceed if Literal Parse Type is on if (parseTypeLiteral) { //Generate an XMLLiteral from its Inner Xml (if any) TypedLiteralEvent lit = new TypedLiteralEvent(node.InnerXml.Normalize(), RdfSpecsHelper.RdfXmlLiteral, node.InnerXml); element.Children.Add(lit); return element; } //Are there Child Nodes? if (node.HasChildNodes) { //Take different actions depending on the Number and Type of Child Nodes if (node.ChildNodes.Count > 1) { //Multiple Child Nodes //Iterate over Child Nodes foreach (XmlNode child in node.ChildNodes) { //Ignore Irrelevant Node Types if (this.IsIgnorableNode(child)) { continue; } //Generate an Event for the Child Node ElementEvent childEvent = this.GenerateEvents(context, child, element); element.Children.Add(childEvent); } } else if (node.ChildNodes[0].NodeType == XmlNodeType.Text) { //Single Child which is a Text Node //Generate a Text Event TextEvent text = new TextEvent(node.InnerText.Normalize(), node.OuterXml); element.Children.Add(text); } else if (node.ChildNodes[0].NodeType == XmlNodeType.CDATA) { //Single Child which is a CData Node TextEvent text = new TextEvent(node.InnerXml.Normalize(), node.OuterXml); element.Children.Add(text); } else { //Single Child which is not a Text Node //Recurse on the single Child Node if (!this.IsIgnorableNode(node.ChildNodes[0])) { ElementEvent childEvent = this.GenerateEvents(context, node.ChildNodes[0], element); element.Children.Add(childEvent); } } } return element; }
/// <summary> /// Reads RDF/XML from the given XML Document /// </summary> /// <param name="g">Graph to load into</param> /// <param name="document">XML Document</param> public void Load(IGraph g, XmlDocument document) { if (g == null) throw new RdfParseException("Cannot read RDF into a null Graph"); if (document == null) throw new RdfParseException("Cannot read RDF from a null XML Document"); try { //Create a new Parser Context and Parse RdfXmlParserContext context = new RdfXmlParserContext(g, document, this._traceparsing); this.Parse(context); } catch (XmlException xmlEx) { //Wrap in a RDF Parse Exception throw new RdfParseException("Unable to Parse this RDF/XML since System.Xml was unable to parse the document into a DOM Tree", xmlEx); } catch (IOException ioEx) { //Wrap in a RDF Parse Exception throw new RdfParseException("Unable to Parse this RDF/XML due to an IO Exception", ioEx); } catch (Exception) { //Throw unexpected errors upwards as-is throw; } }
/// <summary> /// Gets all events from the XML DOM /// </summary> /// <param name="context">Parser Context</param> public void GetAllEvents(RdfXmlParserContext context) { RootEvent root; XmlNodeList nodes = this._document.GetElementsByTagName("rdf:RDF"); if (nodes.Count == 0) { //Not using rdf:RDF root = this.GenerateEventTree(context, this._document.DocumentElement); } else if (nodes.Count > 1) { throw new RdfParseException("XML contains multiple rdf:RDF Nodes and is therefore not a valid RDF/XML Document"); } else { //Must thus be only 1 rdf:RDF element root = this.GenerateEventTree(context, nodes[0]); } this.FlattenEventTree(context, root, 0); }
/// <summary> /// Implementation of the RDF/XML Grammar Production 'doc' /// </summary> /// <param name="context">Parser Context</param> /// <param name="root">Root Event to start applying Productions from</param> private void GrammarProductionDoc(RdfXmlParserContext context, RootEvent root) { //Tracing if (this._traceparsing) { this.ProductionTrace("Doc"); } //Call the RDF Production on the first child if it's an rdf:RDF element if (root.Children[0].QName.Equals("rdf:RDF") || root.Children[0].QName.Equals(":RDF")) { this.GrammarProductionRDF(context, root.Children[0]); } else { //No rdf:RDF element //Drop first element from Queue (which will be a RootEvent) //Skip straight to NodeElementList production //context.Events.Dequeue(); this.GrammarProductionNodeElementList(context, context.Events); } }