/// <summary>
/// Thread Worker method which writes Graphs to the output.
/// </summary>
/// <param name="globalContext">Context for writing the Store.</param>
private void SaveGraphs(ThreadedStoreWriterContext globalContext)
{
try
{
Uri u = null;
while (globalContext.TryGetNextUri(out u))
{
// Get the Graph from the Store
IGraph g = globalContext.Store.Graphs[u];
// Generate the Graph Output and add to Stream
BaseWriterContext context = new BaseWriterContext(g, new System.IO.StringWriter());
String graphContent = GenerateGraphOutput(globalContext, context);
try
{
Monitor.Enter(globalContext.Output);
globalContext.Output.WriteLine(graphContent);
globalContext.Output.Flush();
}
finally
{
Monitor.Exit(globalContext.Output);
}
}
}
catch (ThreadAbortException)
{
// We've been terminated, don't do anything
}
catch (Exception ex)
{
throw new RdfStorageException("Error in Threaded Writer in Thread ID " + Thread.CurrentThread.ManagedThreadId, ex);
}
}
private static void Prettify(string value, BaseWriterContext context)
{
if (context.PrettyPrint)
{
context.Output.Write(value);
}
}
/// <summary>
/// Internal Helper Method for converting a Triple into DOT notation
/// </summary>
/// <param name="t">Triple to convert</param>
/// <param name="context">Writer Context</param>
/// <returns></returns>
private String TripleToDot(Triple t, BaseWriterContext context)
{
StringBuilder output = new StringBuilder();
// 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)
if (t.Subject.NodeType == NodeType.Literal)
{
output.Append(this.NodeToDot(t.Subject, context));
output.Append(" [shape=box];\n");
}
if (t.Object.NodeType == NodeType.Literal)
{
output.Append(this.NodeToDot(t.Object, context));
output.Append(" [shape=box];\n");
}
// Output the actual lines that state the relationship between the Nodes
// We use the Predicate as the Label on the relationship
output.Append(this.NodeToDot(t.Subject, context));
output.Append(" -> ");
output.Append(this.NodeToDot(t.Object, context));
output.Append(" [label=");
output.Append(this.NodeToDot(t.Predicate, context));
output.Append("];");
return(output.ToString());
}
private static string WriteLiteralNode(ILiteralNode literalnode, Triple t, BaseWriterContext context, bool collapseLiterals)
{
// Example output:
// "h" [label = "v", shape = box];
// where h is the hash of the triple containing the literal node
// and v is value of literal node
// Literal nodes are identified either by their value or by their containing triple.
// When identified by value, there will be a single node representing all literals with the same value.
// When identified by triple, there will be a separate node representing each triple that has an object with that value.
var idObject = collapseLiterals ? literalnode as object : t as object;
var nodeId = idObject.GetHashCode().ToString();
GraphVizWriter.Prettify(DOT.Tab, context);
GraphVizWriter.WriteQuoted(nodeId, 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.WriteLiteralNodeLabel(literalnode, context);
context.Output.Write(DOT.Comma);
GraphVizWriter.Prettify(DOT.Space, context);
context.Output.Write(DOT.Shape);
GraphVizWriter.Prettify(DOT.Space, context);
context.Output.Write(DOT.Equal);
GraphVizWriter.Prettify(DOT.Space, context);
context.Output.Write(DOT.Box);
context.Output.Write(DOT.CloseSquare);
context.Output.Write(DOT.NewLine, context);
return(nodeId);
}
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);
}
/// <summary>
/// Generates the Output for a Graph as a String in CSV syntax.
/// </summary>
/// <param name="globalContext">Context for writing the Store.</param>
/// <param name="context">Context for writing the Graph.</param>
/// <returns></returns>
private String GenerateGraphOutput(ThreadedStoreWriterContext globalContext, BaseWriterContext context)
{
if (context.Graph.BaseUri != null)
{
// Named Graphs have a fourth context field added
foreach (Triple t in context.Graph.Triples)
{
GenerateNodeOutput(context, t.Subject, TripleSegment.Subject);
context.Output.Write(',');
GenerateNodeOutput(context, t.Predicate, TripleSegment.Predicate);
context.Output.Write(',');
GenerateNodeOutput(context, t.Object, TripleSegment.Object);
context.Output.Write(',');
context.Output.Write(_formatter.FormatUri(context.Graph.BaseUri));
context.Output.Write("\r\n");
}
}
else
{
// Default Graph has an empty field added
foreach (Triple t in context.Graph.Triples)
{
GenerateNodeOutput(context, t.Subject, TripleSegment.Subject);
context.Output.Write(',');
GenerateNodeOutput(context, t.Predicate, TripleSegment.Predicate);
context.Output.Write(',');
GenerateNodeOutput(context, t.Object, TripleSegment.Object);
context.Output.Write(',');
context.Output.Write("\r\n");
}
}
return(context.Output.ToString());
}
private static void WriteQuoted(string value, BaseWriterContext context)
{
context.Output.Write(DOT.Quote);
context.Output.Write(value);
context.Output.Write(DOT.Quote);
}
private static string ReduceToQName(Uri uri, BaseWriterContext context)
{
if (!context.QNameMapper.ReduceToQName(uri.ToString(), out string result))
{
result = uri.ToString();
}
return(result);
}
/// <summary>
/// Saves a Graph into GraphViz DOT Format
/// </summary>
/// <param name="g">Graph to save</param>
/// <param name="output">Stream to save to</param>
protected override void SaveInternal(IGraph g, TextWriter output)
{
var context = new BaseWriterContext(g, output)
{
PrettyPrint = this.PrettyPrintMode
};
GraphVizWriter.WriteGraph(context, this.CollapseLiterals);
}
/// <summary>
/// Saves a Graph into GraphViz DOT Format
/// </summary>
/// <param name="g">Graph to save</param>
/// <param name="output">Stream to save to</param>
protected override void SaveInternal(IGraph g, TextWriter output)
{
// Start the Graph
output.WriteLine("digraph G {");
BaseWriterContext context = new BaseWriterContext(g, output);
// Write all the Triples to the Graph
foreach (Triple t in g.Triples)
{
output.WriteLine(this.TripleToDot(t, context));
}
// End the Graph
output.WriteLine("}");
}
/// <summary>
/// Generates Output for the given Node
/// </summary>
/// <param name="context">Writer Context</param>
/// <param name="n">Node</param>
/// <param name="segment">Triple Context</param>
private void GenerateNodeOutput(BaseWriterContext context, INode n, TripleSegment segment)
{
switch (n.NodeType)
{
case NodeType.GraphLiteral:
throw new RdfOutputException(WriterErrorMessages.GraphLiteralsUnserializable("TSV"));
case NodeType.Blank:
case NodeType.Literal:
case NodeType.Uri:
context.Output.Write(this._formatter.Format(n));
break;
default:
throw new RdfOutputException(WriterErrorMessages.UnknownNodeTypeUnserializable("TSV"));
}
}
/// <summary>
/// Saves a Graph into GraphViz DOT Format
/// </summary>
/// <param name="g">Graph to save</param>
/// <param name="output">Stream to save to</param>
public void Save(IGraph g, TextWriter output)
{
//Start the Graph
output.WriteLine("digraph G {");
BaseWriterContext context = new BaseWriterContext(g, output);
//Write all the Triples to the Graph
foreach (Triple t in g.Triples)
{
output.WriteLine(this.TripleToDot(t, context));
}
//End the Graph
output.WriteLine("}");
output.Close();
}
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.");
}
}
/// <summary>
/// Internal Helper method for converting Uri Nodes to DOT Notation
/// </summary>
/// <param name="u">Uri Node to convert</param>
/// <param name="context">Writer Context</param>
/// <returns></returns>
private String UriNodeToDot(IUriNode u, BaseWriterContext context)
{
StringBuilder output = new StringBuilder();
output.Append("\"");
//Try QName reduction
String qname;
if (context.QNameMapper.ReduceToQName(u.Uri.ToString(), out qname))
{
//Use the QName
output.Append(qname);
}
else
{
//Use the full Uri
output.Append(u.Uri);
}
output.Append("\"");
return output.ToString();
}
/// <summary>
/// Internal Helper method for converting a Node into DOT notation
/// </summary>
/// <param name="n">Node to Convert</param>
/// <param name="context">Writer Context</param>
/// <returns></returns>
/// <remarks>Currently Graphs containing Graph Literal Nodes cannot be converted</remarks>
private String NodeToDot(INode n, BaseWriterContext context)
{
if (n.NodeType == NodeType.Uri)
{
return(this.UriNodeToDot((IUriNode)n, context));
}
else if (n.NodeType == NodeType.Literal)
{
return(this.LiteralNodeToDot((ILiteralNode)n));
}
else if (n.NodeType == NodeType.Blank)
{
return(this.BlankNodeToDot((IBlankNode)n));
}
else if (n.NodeType == NodeType.GraphLiteral)
{
throw new RdfOutputException("Graphs containing Graph Literal Nodes cannot be converted into GraphViz DOT Format");
}
else
{
throw new RdfOutputException("Unknown Node Type cannot be converted into GraphViz DOT Format");
}
}
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);
}
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);
}
/// <summary>
/// Generates Output for the given Node.
/// </summary>
/// <param name="context">Writer Context.</param>
/// <param name="n">Node.</param>
/// <param name="segment">Triple Segment.</param>
private void GenerateNodeOutput(BaseWriterContext context, INode n, TripleSegment segment)
{
switch (n.NodeType)
{
case NodeType.Blank:
if (segment == TripleSegment.Predicate)
{
throw new RdfOutputException(WriterErrorMessages.BlankPredicatesUnserializable("CSV"));
}
context.Output.Write(_formatter.Format(n));
break;
case NodeType.GraphLiteral:
throw new RdfOutputException(WriterErrorMessages.GraphLiteralsUnserializable("CSV"));
case NodeType.Literal:
if (segment == TripleSegment.Subject)
{
throw new RdfOutputException(WriterErrorMessages.LiteralSubjectsUnserializable("CSV"));
}
if (segment == TripleSegment.Predicate)
{
throw new RdfOutputException(WriterErrorMessages.LiteralPredicatesUnserializable("CSV"));
}
context.Output.Write(_formatter.Format(n));
break;
case NodeType.Uri:
context.Output.Write(_formatter.Format(n));
break;
default:
throw new RdfOutputException(WriterErrorMessages.UnknownNodeTypeUnserializable("CSV"));
}
}
/// <summary>
/// Generates the Output for a Graph as a String in TSV syntax
/// </summary>
/// <param name="globalContext">Context for writing the Store</param>
/// <param name="context">Context for writing the Graph</param>
/// <returns></returns>
private String GenerateGraphOutput(ThreadedStoreWriterContext globalContext, BaseWriterContext context)
{
if (!WriterHelper.IsDefaultGraph(context.Graph.BaseUri))
{
//Named Graphs have a fourth context field added
foreach (Triple t in context.Graph.Triples)
{
this.GenerateNodeOutput(context, t.Subject, TripleSegment.Subject);
context.Output.Write('\t');
this.GenerateNodeOutput(context, t.Predicate, TripleSegment.Predicate);
context.Output.Write('\t');
this.GenerateNodeOutput(context, t.Object, TripleSegment.Object);
context.Output.Write('\t');
context.Output.Write('<');
context.Output.Write(this._formatter.FormatUri(context.Graph.BaseUri));
context.Output.Write('>');
context.Output.Write('\n');
}
}
else
{
//Default Graph has an empty field added
foreach (Triple t in context.Graph.Triples)
{
this.GenerateNodeOutput(context, t.Subject, TripleSegment.Subject);
context.Output.Write('\t');
this.GenerateNodeOutput(context, t.Predicate, TripleSegment.Predicate);
context.Output.Write('\t');
this.GenerateNodeOutput(context, t.Object, TripleSegment.Object);
context.Output.Write('\t');
context.Output.Write('\n');
}
}
return(context.Output.ToString());
}
