/// <summary> /// Gets the next event from the XML stream /// </summary> /// <returns></returns> public IRdfXmlEvent GetNextEvent() { if (this._stop) return null; //If the Root Element is filled then return it if (this._rootEl != null) { IRdfXmlEvent temp = this._rootEl; this._rootEl = null; return temp; } //If Literal Parsing flag is set then we've just read an element which had rdf:parseType="Literal" if (this._parseLiteral) { this._requireEndElement = true; this._parseLiteral = false; this._noRead = true; this._reader.MoveToContent(); String data = this._reader.ReadInnerXml(); return new TypedLiteralEvent(data, RdfSpecsHelper.RdfXmlLiteral, data, this.GetPosition()); } //If we need to return an end element then do so if (this._requireEndElement) { this._requireEndElement = false; this._currentBaseUri = this._baseUris.Pop(); return new EndElementEvent(this.GetPosition()); } //If at EOF throw an error if (this._reader.EOF) throw new RdfParseException("Unable to read further events as the end of the stream has already been reached"); //Otherwise attempt to read the next node bool read = true; if (!this._noRead) { read = this._reader.Read(); } else { this._noRead = false; } if (read) { //Return the appropriate event for the Node Type switch (this._reader.NodeType) { case XmlNodeType.Element: //Element if (this._first) { this._first = false; this._rdfRootSeen = this.IsName("RDF", NamespaceMapper.RDF); this._rootEl = this.GetElement(); RootEvent root = new RootEvent(this.GetBaseUri(), this._reader.Value, this.GetPosition()); root.Children.Add((ElementEvent)this._rootEl); return root; } else { if (!this._first && this.IsName("RDF", NamespaceMapper.RDF)) { if (this._rdfRootSeen) throw new RdfParseException("Unexpected nested rdf:RDF node encountered, this is not valid RDF/XML syntax"); this._noRead = true; this._first = true; return new ClearQueueEvent(); } return this.GetElement(); } case XmlNodeType.EndElement: //End of an Element this._currentBaseUri = this._baseUris.Pop(); if (this.IsName("RDF", NamespaceMapper.RDF)) { this._stop = true; } return new EndElementEvent(this.GetPosition()); case XmlNodeType.Attribute: //Attribute throw new RdfParseException("Unexpected Attribute Node encountered"); case XmlNodeType.Text: return new TextEvent(this._reader.Value, this._reader.Value, this.GetPosition()); case XmlNodeType.CDATA: return new TextEvent(this._reader.Value, this._reader.Value, this.GetPosition()); case XmlNodeType.Document: case XmlNodeType.DocumentType: case XmlNodeType.XmlDeclaration: case XmlNodeType.Comment: case XmlNodeType.ProcessingInstruction: case XmlNodeType.Notation: case XmlNodeType.Whitespace: //Node Types that don't generate events and just indicate to continue reading return this.GetNextEvent(); default: throw new RdfParseException("Unexpected XML Node Type " + this._reader.NodeType.ToString() + " encountered"); } } else { return null; } }
/// <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> /// 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); } }