private static void WriteTriple(Triple triple, BaseWriterContext context, bool collapseLiterals)
{
// Output Node lines for Literal Node so we show them as Boxes
// This is in keeping with Standard Graph representation of RDF
// Literals are shown in Boxes, Uri Nodes in ellipses (GraphViz's default shape)
var subjectId = GraphVizWriter.ProcessNode(triple, TripleSegment.Subject, context, collapseLiterals);
var objectId = GraphVizWriter.ProcessNode(triple, TripleSegment.Object, context, collapseLiterals);
// Output the actual lines that state the relationship between the Nodes
// We use the Predicate as the Label on the relationship
var predicateLabel = GraphVizWriter.ReduceToQName((triple.Predicate as IUriNode).Uri, context);
GraphVizWriter.Prettify(DOT.Tab, context);
GraphVizWriter.WriteQuoted(subjectId, context);
GraphVizWriter.Prettify(DOT.Space, context);
context.Output.Write(DOT.Arrow);
GraphVizWriter.Prettify(DOT.Space, context);
GraphVizWriter.WriteQuoted(objectId, context);
GraphVizWriter.Prettify(DOT.Space, context);
context.Output.Write(DOT.OpenSquare);
context.Output.Write(DOT.Label);
GraphVizWriter.Prettify(DOT.Space, context);
context.Output.Write(DOT.Equal);
GraphVizWriter.Prettify(DOT.Space, context);
GraphVizWriter.WriteQuoted(predicateLabel, context);
context.Output.Write(DOT.CloseSquare);
context.Output.Write(DOT.Semicolon);
GraphVizWriter.Prettify(DOT.NewLine, context);
}
private static string ProcessNode(Triple t, TripleSegment segment, BaseWriterContext context, bool collapseLiterals)
{
var node = GraphVizWriter.GetNode(t, segment);
switch (node)
{
case ILiteralNode literalnode:
return(GraphVizWriter.WriteLiteralNode(literalnode, t, context, collapseLiterals));
case IUriNode uriNode:
return(GraphVizWriter.ReduceToQName(uriNode.Uri, context));
case IBlankNode blankNode:
return(blankNode.ToString());
default:
throw new RdfOutputException("Only Uri nodes, literal nodes and blank nodes can be converted to GraphViz DOT Format.");
}
}
private static void WriteGraph(BaseWriterContext context, bool collapseLiterals)
{
context.Output.Write(DOT.Digraph);
if (context.Graph.BaseUri != null)
{
var graphId = GraphVizWriter.ReduceToQName(context.Graph.BaseUri, context);
GraphVizWriter.Prettify(DOT.Space, context);
GraphVizWriter.WriteQuoted(graphId, context);
}
GraphVizWriter.Prettify(DOT.Space, context);
context.Output.Write(DOT.OpenCurly);
GraphVizWriter.Prettify(DOT.NewLine, context);
foreach (var t in context.Graph.Triples)
{
GraphVizWriter.WriteTriple(t, context, collapseLiterals);
}
context.Output.Write(DOT.CloseCurly);
}
private static void WriteLiteralNodeLabel(ILiteralNode literalnode, BaseWriterContext context)
{
var nodeValue = GraphVizWriter.Escape(literalnode.Value);
context.Output.Write(DOT.Quote);
context.Output.Write(nodeValue);
if (!string.IsNullOrEmpty(literalnode.Language))
{
context.Output.Write("@");
context.Output.Write(literalnode.Language);
}
if (literalnode.DataType != null)
{
string datatype = GraphVizWriter.ReduceToQName(literalnode.DataType, context);
context.Output.Write("^^");
context.Output.Write(datatype);
}
context.Output.Write(DOT.Quote);
}
