/// <summary>
/// Evaluates the Graph Clause by setting up the dataset, applying the pattern and then generating additional bindings if necessary.
/// </summary>
/// <param name="context">Evaluation Context.</param>
/// <returns></returns>
public BaseMultiset Evaluate(SparqlEvaluationContext context)
{
// Q: Can we optimise GRAPH when the input is the Null Multiset to just return the Null Multiset?
bool datasetOk = false;
try
{
List <String> activeGraphs = new List <string>();
// Get the URIs of Graphs that should be evaluated over
if (_graphSpecifier.TokenType != Token.VARIABLE)
{
switch (_graphSpecifier.TokenType)
{
case Token.URI:
case Token.QNAME:
Uri activeGraphUri = UriFactory.Create(Tools.ResolveUriOrQName(_graphSpecifier, context.Query.NamespaceMap, context.Query.BaseUri));
if (context.Data.HasGraph(activeGraphUri))
{
// If the Graph is explicitly specified and there are FROM/FROM NAMED present then the Graph
// URI must be in the graphs specified by a FROM/FROM NAMED or the result is null
if (context.Query == null ||
((!context.Query.DefaultGraphs.Any() && !context.Query.NamedGraphs.Any()) ||
context.Query.NamedGraphs.Any(u => EqualityHelper.AreUrisEqual(activeGraphUri, u)))
)
{
// Either there was no Query
// OR there were no Default/Named Graphs (hence any Graph URI is permitted)
// OR the specified URI was a Named Graph URI
// In any case we can go ahead and set the active Graph
activeGraphs.Add(activeGraphUri.AbsoluteUri);
}
else
{
// The specified URI was not present in the Named Graphs so return null
context.OutputMultiset = new NullMultiset();
return(context.OutputMultiset);
}
}
else
{
// If specifies a specific Graph and not in the Dataset result is a null multiset
context.OutputMultiset = new NullMultiset();
return(context.OutputMultiset);
}
break;
default:
throw new RdfQueryException("Cannot use a '" + _graphSpecifier.GetType().ToString() + "' Token to specify the Graph for a GRAPH clause");
}
}
else
{
String gvar = _graphSpecifier.Value.Substring(1);
// Watch out for the case in which the Graph Variable is not bound for all Sets in which case
// we still need to operate over all Graphs
if (context.InputMultiset.ContainsVariable(gvar) && context.InputMultiset.Sets.All(s => s[gvar] != null))
{
// If there are already values bound to the Graph variable for all Input Solutions then we limit the Query to those Graphs
List <Uri> graphUris = new List <Uri>();
foreach (ISet s in context.InputMultiset.Sets)
{
INode temp = s[gvar];
if (temp == null)
{
continue;
}
if (temp.NodeType != NodeType.Uri)
{
continue;
}
activeGraphs.Add(temp.ToString());
graphUris.Add(((IUriNode)temp).Uri);
}
}
else
{
// Nothing yet bound to the Graph Variable so the Query is over all the named Graphs
if (context.Query != null && context.Query.NamedGraphs.Any())
{
// Query specifies one/more named Graphs
activeGraphs.AddRange(context.Query.NamedGraphs.Select(u => u.AbsoluteUri));
}
else if (context.Query != null && context.Query.DefaultGraphs.Any() && !context.Query.NamedGraphs.Any())
{
// Gives null since the query dataset does not include any named graphs
context.OutputMultiset = new NullMultiset();
return(context.OutputMultiset);
}
else
{
// Query is over entire dataset/default Graph since no named Graphs are explicitly specified
activeGraphs.AddRange(context.Data.GraphUris.Select(u => u.ToSafeString()));
}
}
}
// Remove all duplicates from Active Graphs to avoid duplicate results
activeGraphs = activeGraphs.Distinct().ToList();
// Evaluate the inner pattern
BaseMultiset initialInput = context.InputMultiset;
BaseMultiset finalResult = new Multiset();
// Evalute for each Graph URI and union the results
foreach (String uri in activeGraphs)
{
// Always use the same Input for each Graph URI and set that Graph to be the Active Graph
// Be sure to translate String.Empty back to the null URI to select the default graph
// correctly
context.InputMultiset = initialInput;
Uri currGraphUri = (uri.Equals(String.Empty)) ? null : UriFactory.Create(uri);
// Set Active Graph
if (currGraphUri == null)
{
// GRAPH operates over named graphs only so default graph gets skipped
continue;
}
// The result of the HasGraph() call is ignored we just make it so datasets with any kind of
// load on demand behaviour work properly
context.Data.HasGraph(currGraphUri);
// All we actually care about is setting the active graph
context.Data.SetActiveGraph(currGraphUri);
datasetOk = true;
// Evaluate for the current Active Graph
BaseMultiset result = context.Evaluate(_pattern);
// Merge the Results into our overall Results
if (result is NullMultiset)
{
// Don't do anything, adds nothing to the results
}
else if (result is IdentityMultiset)
{
// Adds a single row to the results
if (_graphSpecifier.TokenType == Token.VARIABLE)
{
// Include graph variable if not yet bound
INode currGraph = new UriNode(null, currGraphUri);
Set s = new Set();
s.Add(_graphSpecifier.Value.Substring(1), currGraph);
finalResult.Add(s);
}
else
{
finalResult.Add(new Set());
}
}
else
{
// If the Graph Specifier is a Variable then we must either bind the
// variable or eliminate solutions which have an incorrect value for it
if (_graphSpecifier.TokenType == Token.VARIABLE)
{
String gvar = _graphSpecifier.Value.Substring(1);
INode currGraph = new UriNode(null, currGraphUri);
foreach (int id in result.SetIDs.ToList())
{
ISet s = result[id];
if (s[gvar] == null)
{
// If Graph Variable is not yet bound for solution bind it
s.Add(gvar, currGraph);
}
else if (!s[gvar].Equals(currGraph))
{
// If Graph Variable is bound for solution and doesn't match
// current Graph then we have to remove the solution
result.Remove(id);
}
}
}
// Union solutions into the Results
finalResult.Union(result);
}
// Reset the Active Graph after each pass
context.Data.ResetActiveGraph();
datasetOk = false;
}
// Return the final result
if (finalResult.IsEmpty)
{
finalResult = new NullMultiset();
}
context.OutputMultiset = finalResult;
}
finally
{
if (datasetOk)
{
context.Data.ResetActiveGraph();
}
}
return(context.OutputMultiset);
}
/// <summary>
/// Gets whether the given URI represents the default graph of the dataset
/// </summary>
/// <param name="graphUri">Graph URI</param>
/// <returns></returns>
protected bool IsDefaultGraph(Uri graphUri)
{
return(EqualityHelper.AreUrisEqual(graphUri, this._defaultGraphUri));
}
/// <summary>
/// Evaluates the Graph Clause by setting up the dataset, applying the pattern and then generating additional bindings if necessary
/// </summary>
/// <param name="context">Evaluation Context</param>
/// <returns></returns>
public BaseMultiset Evaluate(SparqlEvaluationContext context)
{
BaseMultiset result;
//Q: Can we optimise GRAPH when the input is the Null Multiset to just return the Null Multiset?
if (this._pattern is Bgp && ((Bgp)this._pattern).IsEmpty)
{
//Optimise the case where we have GRAPH ?g {} by not setting the Graph and just returning
//a Null Multiset
result = new NullMultiset();
}
else
{
bool datasetOk = false;
try
{
List <String> activeGraphs = new List <string>();
//Get the URIs of Graphs that should be evaluated over
if (this._graphSpecifier.TokenType != Token.VARIABLE)
{
switch (this._graphSpecifier.TokenType)
{
case Token.URI:
case Token.QNAME:
Uri activeGraphUri = new Uri(Tools.ResolveUriOrQName(this._graphSpecifier, context.Query.NamespaceMap, context.Query.BaseUri));
if (context.Data.HasGraph(activeGraphUri))
{
//If the Graph is explicitly specified and there are FROM NAMED present then the Graph
//URI must be in the graphs specified by a FROM NAMED or the result is null
if (context.Query != null &&
((!context.Query.DefaultGraphs.Any() && !context.Query.NamedGraphs.Any()) ||
context.Query.DefaultGraphs.Any(u => EqualityHelper.AreUrisEqual(activeGraphUri, u)) ||
context.Query.NamedGraphs.Any(u => EqualityHelper.AreUrisEqual(activeGraphUri, u)))
)
{
//Either there was no Query OR there were no Default/Named Graphs OR
//the specified URI was either a Default/Named Graph URI
//In any case we can go ahead and set the active Graph
activeGraphs.Add(activeGraphUri.ToString());
}
else
{
//The specified URI was not present in the Default/Named Graphs so return null
context.OutputMultiset = new NullMultiset();
return(context.OutputMultiset);
}
}
else
{
//If specifies a specific Graph and not in the Dataset result is a null multiset
context.OutputMultiset = new NullMultiset();
return(context.OutputMultiset);
}
break;
default:
throw new RdfQueryException("Cannot use a '" + this._graphSpecifier.GetType().ToString() + "' Token to specify the Graph for a GRAPH clause");
}
}
else
{
String gvar = this._graphSpecifier.Value.Substring(1);
//Watch out for the case in which the Graph Variable is not bound for all Sets in which case
//we still need to operate over all Graphs
if (context.InputMultiset.ContainsVariable(gvar) && context.InputMultiset.Sets.All(s => s[gvar] != null))
{
//If there are already values bound to the Graph variable for all Input Solutions then we limit the Query to those Graphs
List <Uri> graphUris = new List <Uri>();
foreach (ISet s in context.InputMultiset.Sets)
{
INode temp = s[gvar];
if (temp != null)
{
if (temp.NodeType == NodeType.Uri)
{
activeGraphs.Add(temp.ToString());
graphUris.Add(((IUriNode)temp).Uri);
}
}
}
}
else
{
//Nothing yet bound to the Graph Variable so the Query is over all the named Graphs
if (context.Query != null && context.Query.NamedGraphs.Any())
{
//Query specifies one/more named Graphs
activeGraphs.AddRange(context.Query.NamedGraphs.Select(u => u.ToString()));
}
else
{
//Query is over entire dataset/default Graph since no named Graphs are explicitly specified
activeGraphs.AddRange(context.Data.GraphUris.Select(u => u.ToSafeString()));
}
}
}
//Remove all duplicates from Active Graphs to avoid duplicate results
activeGraphs = activeGraphs.Distinct().ToList();
//Evaluate the inner pattern
BaseMultiset initialInput = context.InputMultiset;
BaseMultiset finalResult = new Multiset();
//Evalute for each Graph URI and union the results
foreach (String uri in activeGraphs)
{
//Always use the same Input for each Graph URI and set that Graph to be the Active Graph
//Be sure to translate String.Empty back to the null URI to select the default graph
//correctly
context.InputMultiset = initialInput;
Uri currGraphUri = (uri.Equals(String.Empty)) ? null : new Uri(uri);
//This bit of logic takes care of the fact that calling SetActiveGraph((Uri)null) resets the
//Active Graph to be the default graph which if the default graph is null is usually the Union of
//all Graphs in the Store
if (currGraphUri == null && context.Data.DefaultGraph == null && context.Data.UsesUnionDefaultGraph)
{
if (context.Data.HasGraph(null))
{
context.Data.SetActiveGraph(context.Data[null]);
}
else
{
continue;
}
}
else
{
context.Data.SetActiveGraph(currGraphUri);
}
datasetOk = true;
//Evaluate for the current Active Graph
result = context.Evaluate(this._pattern);
//Merge the Results into our overall Results
if (result is NullMultiset || result is IdentityMultiset)
{
//Don't do anything
}
else
{
//If the Graph Specifier is a Variable then we must either bind the
//variable or eliminate solutions which have an incorrect value for it
if (this._graphSpecifier.TokenType == Token.VARIABLE)
{
String gvar = this._graphSpecifier.Value.Substring(1);
INode currGraph = (currGraphUri == null) ? null : new UriNode(null, currGraphUri);
foreach (int id in result.SetIDs.ToList())
{
ISet s = result[id];
if (s[gvar] == null)
{
//If Graph Variable is not yet bound for solution bind it
s.Add(gvar, currGraph);
}
else if (!s[gvar].Equals(currGraph))
{
//If Graph Variable is bound for solution and doesn't match
//current Graph then we have to remove the solution
result.Remove(id);
}
}
}
//Union solutions into the Results
finalResult.Union(result);
}
//Reset the Active Graph after each pass
context.Data.ResetActiveGraph();
datasetOk = false;
}
//Return the final result
if (finalResult.IsEmpty)
{
finalResult = new NullMultiset();
}
context.OutputMultiset = finalResult;
}
finally
{
if (datasetOk)
{
context.Data.ResetActiveGraph();
}
}
}
return(context.OutputMultiset);
}
/// <summary>
/// Evaluates the Command in the given Context
/// </summary>
/// <param name="context">Evaluation Context</param>
public override void Evaluate(SparqlUpdateEvaluationContext context)
{
try
{
//If Source and Destination are same this is a no-op
if (EqualityHelper.AreUrisEqual(this._sourceUri, this._destUri))
{
return;
}
if (context.Data.HasGraph(this._sourceUri))
{
//Get the Source Graph
IGraph source = context.Data.GetModifiableGraph(this._sourceUri);
//Create/Delete/Clear the Destination Graph
IGraph dest;
if (context.Data.HasGraph(this._destUri))
{
if (this._destUri == null)
{
dest = context.Data.GetModifiableGraph(this._destUri);
dest.Clear();
}
else
{
context.Data.RemoveGraph(this._destUri);
dest = new Graph();
dest.BaseUri = this._destUri;
context.Data.AddGraph(dest);
dest = context.Data.GetModifiableGraph(this._destUri);
}
}
else
{
dest = new Graph();
dest.BaseUri = this._destUri;
context.Data.AddGraph(dest);
}
//Move data from the Source into the Destination
dest.Merge(source);
//Delete/Clear the Source Graph
if (this._sourceUri == null)
{
source.Clear();
}
else
{
context.Data.RemoveGraph(this._sourceUri);
}
}
else
{
//Only show error if not Silent
if (!this._silent)
{
if (this._sourceUri != null)
{
throw new SparqlUpdateException("Cannot MOVE from Graph <" + this._sourceUri.AbsoluteUri + "> as it does not exist");
}
else
{
//This would imply a more fundamental issue with the Dataset not understanding that null means default graph
throw new SparqlUpdateException("Cannot MOVE from the Default Graph as it does not exist");
}
}
}
}
catch
{
//If not silent throw the exception upwards
if (!this._silent)
{
throw;
}
}
}
/// <summary>
/// Constructs a Full Text Match property function.
/// </summary>
/// <param name="info">Property Function information.</param>
public FullTextMatchPropertyFunction(PropertyFunctionInfo info)
{
if (info == null)
{
throw new ArgumentNullException("info");
}
if (!EqualityHelper.AreUrisEqual(info.FunctionUri, this.FunctionUri))
{
throw new ArgumentException("Property Function information is not valid for this function");
}
//Get basic arguments
this._matchVar = info.SubjectArgs[0];
if (this._matchVar.VariableName != null)
{
this._vars.Add(this._matchVar.VariableName);
}
if (info.SubjectArgs.Count == 2)
{
this._scoreVar = info.SubjectArgs[1];
if (this._scoreVar.VariableName != null)
{
this._vars.Add(this._scoreVar.VariableName);
}
}
//Check extended arguments
this._searchVar = info.ObjectArgs[0];
if (this._searchVar.VariableName != null)
{
this._vars.Add(this._searchVar.VariableName);
}
switch (info.ObjectArgs.Count)
{
case 1:
break;
case 2:
PatternItem arg = info.ObjectArgs[1];
if (arg.VariableName != null)
{
throw new RdfQueryException("Cannot use a variable as the limit/score threshold for full text queries, must use a numeric constant");
}
IValuedNode n = ((NodeMatchPattern)arg).Node.AsValuedNode();
switch (n.NumericType)
{
case SparqlNumericType.Integer:
this._limit = (int)n.AsInteger();
break;
case SparqlNumericType.Decimal:
case SparqlNumericType.Double:
case SparqlNumericType.Float:
this._threshold = n.AsDouble();
break;
default:
throw new RdfQueryException("Cannot use a non-numeric constant as the limit/score threshold for full text queries, must use a numeric constant");
}
break;
case 3:
default:
PatternItem arg1 = info.ObjectArgs[1];
PatternItem arg2 = info.ObjectArgs[2];
if (arg1.VariableName != null || arg2.VariableName != null)
{
throw new RdfQueryException("Cannot use a variable as the limit/score threshold for full text queries, must use a numeric constant");
}
IValuedNode n1 = ((NodeMatchPattern)arg1).Node.AsValuedNode();
switch (n1.NumericType)
{
case SparqlNumericType.NaN:
throw new RdfQueryException("Cannot use a non-numeric constant as the score threshold for full text queries, must use a numeric constant");
default:
this._threshold = n1.AsDouble();
break;
}
IValuedNode n2 = ((NodeMatchPattern)arg2).Node.AsValuedNode();
switch (n2.NumericType)
{
case SparqlNumericType.NaN:
throw new RdfQueryException("Cannot use a non-numeric constant as the limit for full text queries, must use a numeric constant");
default:
this._limit = (int)n2.AsInteger();
break;
}
break;
}
}