/// <summary>
/// Loads RDF using the RDF Handler using the settings the Reader was instantiated with
/// </summary>
/// <param name="handler">RDF Handler to use</param>
/// <param name="parameters">Parameters indicating where to read from</param>
public void Load(IRdfHandler handler, IStoreParams parameters)
{
if (parameters is FolderStoreParams)
{
//Create the Parser Context
FolderStoreParserContext context = new FolderStoreParserContext(handler, (FolderStoreParams)parameters);
//Create the Folder
if (!Directory.Exists(context.Folder))
{
throw new RdfStorageException("Cannot read a Folder Store from a Folder that doesn't exist");
}
//Read list of Graphs and Queue Filenames of Graphs for reading by the Threads
StreamReader graphlist = new StreamReader(Path.Combine(context.Folder, "graphs.fstore"));
//First line contains format information
String ext = graphlist.ReadLine();
if (context.Format == FolderStoreFormat.AutoDetect)
{
if (ext.Equals(".ttl"))
{
context.Format = FolderStoreFormat.Turtle;
}
else if (ext.Equals(".n3"))
{
context.Format = FolderStoreFormat.Notation3;
}
else if (ext.Equals(".rdf"))
{
context.Format = FolderStoreFormat.RdfXml;
}
else
{
throw new RdfStorageException("Folder Store Format auto-detection failed");
}
}
String file;
while (!graphlist.EndOfStream)
{
file = graphlist.ReadLine();
if (!file.Equals(String.Empty))
{
context.Add(file);
}
}
graphlist.Close();
//Start making the async calls
List<IAsyncResult> results = new List<IAsyncResult>();
LoadGraphsDelegate d = new LoadGraphsDelegate(this.LoadGraphs);
for (int i = 0; i < context.Threads; i++)
{
results.Add(d.BeginInvoke(context, null, null));
}
//Wait for all the async calls to complete
WaitHandle.WaitAll(results.Select(r => r.AsyncWaitHandle).ToArray());
RdfThreadedParsingException parsingEx = new RdfThreadedParsingException("One/more errors occurred while parsing RDF from a Folder Store using a multi-threaded parsing process");
foreach (IAsyncResult result in results)
{
try
{
d.EndInvoke(result);
}
catch (Exception ex)
{
parsingEx.AddException(ex);
}
}
//If there were any errors we'll throw an RdfThreadedOutputException now
if (parsingEx.InnerExceptions.Any()) throw parsingEx;
}
else
{
throw new RdfStorageException("Parameters for the FolderStoreReader must be of type FolderStoreParams");
}
}
/// <summary>
/// Internal Method which performs multi-threaded reading of data
/// </summary>
private void LoadGraphs(FolderStoreParserContext context)
{
//Create the relevant Parser
IRdfReader parser;
switch (context.Format)
{
case FolderStoreFormat.Turtle:
parser = new TurtleParser();
break;
case FolderStoreFormat.Notation3:
parser = new Notation3Parser();
break;
case FolderStoreFormat.RdfXml:
parser = new RdfXmlParser();
break;
default:
parser = new TurtleParser();
break;
}
try
{
String file = context.GetNextFilename();
while (file != null)
{
//Read from Disk
Graph g = new Graph();
String sourceFile = Path.Combine(context.Folder, file);
parser.Load(g, sourceFile);
//Add to Graph Collection
foreach (Triple t in g.Triples)
{
if (context.Terminated) break;
if (!context.Handler.HandleTriple(t)) ParserHelper.Stop();
}
if (context.Terminated) break;
//Get the Next Filename
file = context.GetNextFilename();
}
}
catch (ThreadAbortException)
{
//We've been terminated, don't do anything
#if !SILVERLIGHT
Thread.ResetAbort();
#endif
}
catch (RdfParsingTerminatedException)
{
context.Terminated = true;
context.ClearFilenames();
}
catch (Exception ex)
{
throw new RdfStorageException("Error in Threaded Reader in Thread ID " + Thread.CurrentThread.ManagedThreadId, ex);
}
}
