beagle r4401 - branches/beagle-rdf/RDFAdapter

[dbera svn gnome org]

Author: dbera
Date: Sat Jan 19 00:45:21 2008
New Revision: 4401
URL: http://svn.gnome.org/viewvc/beagle?rev=4401&view=rev

Log:
Add a simple Beagle RDF adapter and a test client to do query against the adapter. Files from  
Enrico Minack <minack l3s de>.


Added:
   branches/beagle-rdf/RDFAdapter/
   branches/beagle-rdf/RDFAdapter/BeagleSource.cs   (contents, props changed)
   branches/beagle-rdf/RDFAdapter/SemWebClient.cs   (contents, props changed)

Added: branches/beagle-rdf/RDFAdapter/BeagleSource.cs
==============================================================================
--- (empty file)
+++ branches/beagle-rdf/RDFAdapter/BeagleSource.cs	Sat Jan 19 00:45:21 2008
@@ -0,0 +1,129 @@
+//
+// BeagleSource.cs
+//
+// Copyright (C) 2007 Enrico Minack <minack l3s de>
+//
+
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+//
+
+using Beagle;
+using SemWeb;
+using System;
+
+public class BeagleSource : SelectableSource {
+
+	// counts the statements that match the template and returns if this number > 0
+	public bool Contains (Statement template)
+	{
+		StatementCounterSink sink = new StatementCounterSink ();
+		this.Select (template, sink);
+		return sink.StatementCount > 0;
+	}
+
+	// we provide only distinct statements
+	public bool Distinct {
+		get { return true; }
+	}
+
+	// this simply forwards to a select all
+	public void Select (StatementSink sink)
+	{
+		this.Select (Statement.All, sink);
+	}
+
+	public void Select (Statement template, StatementSink sink)
+	{
+		// extract the fields for easy access
+		Entity subj = template.Subject;
+		Entity pred = template.Predicate;
+		Resource obj = template.Object;
+
+		// convert the SemWeb fields to the RDFQuery fields
+		Uri s    = (subj == null) ? null : new Uri (subj.Uri);
+		string p = (pred == null) ? null : pred.Uri;
+		string o = null;
+
+		if (obj != null) {
+			if (obj is Literal) {
+				Literal l = (Literal) obj;
+				o = l.Value;
+			} else {
+				o = obj.Uri;
+			}
+		}
+
+		// extract the property type from the property
+		// e.g. from prop:k:beagle:MimeType
+		PropertyType ptype = PropertyType.Internal;
+
+		if (p != null) {
+			if ((p.Length > 7) && p.StartsWith ("prop:")) {
+				switch (p [5]) {
+					case 't': ptype = PropertyType.Text; break;
+					case 'k': ptype = PropertyType.Keyword; break;
+					case 'd': ptype = PropertyType.Date; break;
+				}
+				// remove the prop:?:, which will be added by beagle later
+				p = p.Substring (7);
+			}
+		}
+
+		RDFQuery query = new RDFQuery (s, p, ptype, o);
+		RDFQueryResult result = (RDFQueryResult) query.Send ();
+		
+		foreach (string uri in result.Matches) {
+			Entity subject = new Entity (uri);
+			Entity predicate = new Entity ("beagle:unknown");
+			Resource _object = null;
+			
+			// for some properties the object is actually an URI (Entity)
+			if (predicate == "Uri" || predicate == "ParentUri" || predicate == "ParentDirUri")
+				_object = new Entity("beagle:unkown");
+			else
+				_object = new Literal("beagle:unkown");
+
+			// now create a the statement and add it to the result
+			Statement st = new Statement (subject, predicate, _object);
+			sink.Add (st);
+		}
+	}
+
+	public void Select (SelectFilter filter, StatementSink sink)
+	{
+		throw new NotImplementedException ("Select");
+		// FIXME: not implemented yet, SelectFilter are a little more complex
+		// than Statements with wildcards
+	}
+
+	// copied from SemWeb/Store.cs
+	internal class StatementCounterSink : StatementSink {
+		int counter = 0;
+
+		public int StatementCount {
+			get { return counter; }
+		}
+
+		public bool Add (Statement statement) {
+			counter ++;
+			return true;
+		}
+	}
+}

Added: branches/beagle-rdf/RDFAdapter/SemWebClient.cs
==============================================================================
--- (empty file)
+++ branches/beagle-rdf/RDFAdapter/SemWebClient.cs	Sat Jan 19 00:45:21 2008
@@ -0,0 +1,38 @@
+//
+// SemWebClient.cs
+//
+// Copyright (C) 2007 Enrico Minack <minack l3s de>
+//
+
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+//
+
+using SemWeb;
+
+public class SemWebClient {
+	public static void Main (string[] args)
+	{
+		RdfWriter writer = new N3Writer (System.Console.Out);
+		SelectableSource source = new BeagleSource();
+		source.Select (Statement.All, writer);
+		writer.Close ();
+	}
+}
+