/// <summary>
/// Evaluates the Command in the given Context
/// </summary>
/// <param name="context">Evaluation Context</param>
public override void Evaluate(SparqlUpdateEvaluationContext context)
{
bool defGraphOk = false;
bool datasetOk = false;
try
{
//First evaluate the WHERE pattern to get the affected bindings
ISparqlAlgebra where = this._wherePattern.ToAlgebra();
if (context.Commands != null)
{
where = context.Commands.ApplyAlgebraOptimisers(where);
}
//Set Active Graph for the WHERE based upon the WITH clause
//Don't bother if there are USING URIs as these would override any Active Graph we set here
//so we can save ourselves the effort of doing this
if (!this.UsingUris.Any())
{
if (this._graphUri != null)
{
context.Data.SetActiveGraph(this._graphUri);
defGraphOk = true;
}
else
{
context.Data.SetActiveGraph((Uri)null);
defGraphOk = true;
}
}
//We need to make a dummy SparqlQuery object since if the Command has used any
//USING/USING NAMEDs along with GRAPH clauses then the algebra needs to have the
//URIs available to it which it gets from the Query property of the Context
//object
SparqlQuery query = new SparqlQuery();
foreach (Uri u in this.UsingUris)
{
query.AddDefaultGraph(u);
}
foreach (Uri u in this.UsingNamedUris)
{
query.AddNamedGraph(u);
}
SparqlEvaluationContext queryContext = new SparqlEvaluationContext(query, context.Data, context.QueryProcessor);
if (this.UsingUris.Any())
{
//If there are USING URIs set the Active Graph to be formed of the Graphs with those URIs
context.Data.SetActiveGraph(this._usingUris);
datasetOk = true;
}
BaseMultiset results = queryContext.Evaluate(where);
if (results is IdentityMultiset)
{
results = new SingletonMultiset(results.Variables);
}
if (this.UsingUris.Any())
{
//If there are USING URIs reset the Active Graph afterwards
//Also flag the dataset as no longer being OK as this flag is used in the finally
//block to determine whether the Active Graph needs resetting which it may do if the
//evaluation of the
context.Data.ResetActiveGraph();
datasetOk = false;
}
//Reset Active Graph for the WHERE
if (defGraphOk)
{
context.Data.ResetActiveGraph();
defGraphOk = false;
}
//Get the Graph from which we are deleting
IGraph g = context.Data.GetModifiableGraph(this._graphUri);
//Delete the Triples for each Solution
foreach (ISet s in results.Sets)
{
List <Triple> deletedTriples = new List <Triple>();
//Triples from raw Triple Patterns
try
{
ConstructContext constructContext = new ConstructContext(g, s, true);
foreach (IConstructTriplePattern p in this._deletePattern.TriplePatterns.OfType <IConstructTriplePattern>())
{
try
{
deletedTriples.Add(p.Construct(constructContext));
}
catch (RdfQueryException)
{
//If we get an error here then we couldn't construct a specific Triple
//so we continue anyway
}
}
g.Retract(deletedTriples);
}
catch (RdfQueryException)
{
//If we throw an error this means we couldn't construct for this solution so the
//solution is ignored this graph
}
//Triples from GRAPH clauses
foreach (GraphPattern gp in this._deletePattern.ChildGraphPatterns)
{
deletedTriples.Clear();
try
{
String graphUri;
switch (gp.GraphSpecifier.TokenType)
{
case Token.URI:
graphUri = gp.GraphSpecifier.Value;
break;
case Token.VARIABLE:
String graphVar = gp.GraphSpecifier.Value.Substring(1);
if (s.ContainsVariable(graphVar))
{
INode temp = s[graphVar];
if (temp == null)
{
//If the Variable is not bound then skip
continue;
}
else if (temp.NodeType == NodeType.Uri)
{
graphUri = temp.ToSafeString();
}
else
{
//If the Variable is not bound to a URI then skip
continue;
}
}
else
{
//If the Variable is not bound for this solution then skip
continue;
}
break;
default:
//Any other Graph Specifier we have to ignore this solution
continue;
}
//If the Dataset doesn't contain the Graph then no need to do the Deletions
if (!context.Data.HasGraph(UriFactory.Create(graphUri)))
{
continue;
}
//Do the actual Deletions
IGraph h = context.Data.GetModifiableGraph(UriFactory.Create(graphUri));
ConstructContext constructContext = new ConstructContext(h, s, true);
foreach (IConstructTriplePattern p in gp.TriplePatterns.OfType <IConstructTriplePattern>())
{
try
{
deletedTriples.Add(p.Construct(constructContext));
}
catch (RdfQueryException)
{
//If we get an error here then we couldn't construct a specific
//triple so we continue anyway
}
}
h.Retract(deletedTriples);
}
catch (RdfQueryException)
{
//If we get an error here this means we couldn't construct for this solution so the
//solution is ignored for this graph
}
}
}
}
finally
{
//If the Dataset was set and an error occurred in doing the WHERE clause then
//we'll need to Reset the Active Graph
if (datasetOk)
{
context.Data.ResetActiveGraph();
}
if (defGraphOk)
{
context.Data.ResetActiveGraph();
}
}
}
/// <summary>
/// Evaluates the Command in the given Context
/// </summary>
/// <param name="context">Evaluation Context</param>
public override void Evaluate(SparqlUpdateEvaluationContext context)
{
bool datasetOk = false;
bool defGraphOk = false;
try
{
// First evaluate the WHERE pattern to get the affected bindings
ISparqlAlgebra where = _wherePattern.ToAlgebra();
if (context.Commands != null)
{
where = context.Commands.ApplyAlgebraOptimisers(where);
}
// Set Active Graph for the WHERE
// Don't bother if there are USING URIs as these would override any Active Graph we set here
// so we can save ourselves the effort of doing this
if (!UsingUris.Any())
{
if (_graphUri != null)
{
context.Data.SetActiveGraph(_graphUri);
defGraphOk = true;
}
else
{
context.Data.SetActiveGraph((Uri)null);
defGraphOk = true;
}
}
// We need to make a dummy SparqlQuery object since if the Command has used any
// USING NAMEDs along with GRAPH clauses then the algebra needs to have the
// URIs available to it which it gets from the Query property of the Context
// object
SparqlQuery query = new SparqlQuery();
foreach (Uri u in UsingUris)
{
query.AddDefaultGraph(u);
}
foreach (Uri u in UsingNamedUris)
{
query.AddNamedGraph(u);
}
SparqlEvaluationContext queryContext = new SparqlEvaluationContext(query, context.Data, context.QueryProcessor);
if (UsingUris.Any())
{
// If there are USING URIs set the Active Graph to be formed of the Graphs with those URIs
context.Data.SetActiveGraph(_usingUris);
datasetOk = true;
}
BaseMultiset results = queryContext.Evaluate(where);
if (results is IdentityMultiset)
{
results = new SingletonMultiset(results.Variables);
}
if (UsingUris.Any())
{
// If there are USING URIs reset the Active Graph afterwards
// Also flag the dataset as no longer being OK as this flag is used in the finally
// block to determine whether the Active Graph needs resetting which it may do if the
// evaluation of the query fails for any reason
context.Data.ResetActiveGraph();
datasetOk = false;
}
// Reset Active Graph for the WHERE
if (defGraphOk)
{
context.Data.ResetActiveGraph();
defGraphOk = false;
}
// TODO: Need to detect when we create a Graph for Insertion but then fail to insert anything since in this case the Inserted Graph should be removed
// Get the Graph to which we are inserting Triples with no explicit Graph clause
IGraph g = null;
if (_insertPattern.TriplePatterns.Count > 0)
{
if (context.Data.HasGraph(_graphUri))
{
g = context.Data.GetModifiableGraph(_graphUri);
}
else
{
// insertedGraphs.Add(this._graphUri);
g = new Graph();
g.BaseUri = _graphUri;
context.Data.AddGraph(g);
g = context.Data.GetModifiableGraph(_graphUri);
}
}
// Keep a record of graphs to which we insert
MultiDictionary <Uri, IGraph> graphs = new MultiDictionary <Uri, IGraph>(u => (u != null ? u.GetEnhancedHashCode() : 0), true, new UriComparer(), MultiDictionaryMode.AVL);
// Insert the Triples for each Solution
foreach (ISet s in results.Sets)
{
List <Triple> insertedTriples = new List <Triple>();
try
{
// Create a new Construct Context for each Solution
ConstructContext constructContext = new ConstructContext(null, s, true);
// Triples from raw Triple Patterns
if (_insertPattern.TriplePatterns.Count > 0)
{
foreach (IConstructTriplePattern p in _insertPattern.TriplePatterns.OfType <IConstructTriplePattern>())
{
try
{
insertedTriples.Add(p.Construct(constructContext));
}
catch (RdfQueryException)
{
// If we throw an error this means we couldn't construct a specific Triple
// so we continue anyway
}
}
g.Assert(insertedTriples);
}
// Triples from GRAPH clauses
foreach (GraphPattern gp in _insertPattern.ChildGraphPatterns)
{
insertedTriples.Clear();
try
{
String graphUri;
switch (gp.GraphSpecifier.TokenType)
{
case Token.URI:
graphUri = gp.GraphSpecifier.Value;
break;
case Token.VARIABLE:
String graphVar = gp.GraphSpecifier.Value.Substring(1);
if (s.ContainsVariable(graphVar))
{
INode temp = s[graphVar];
if (temp == null)
{
// If the Variable is not bound then skip
continue;
}
if (temp.NodeType == NodeType.Uri)
{
graphUri = temp.ToSafeString();
}
else
{
// If the Variable is not bound to a URI then skip
continue;
}
}
else
{
// If the Variable is not bound for this solution then skip
continue;
}
break;
default:
// Any other Graph Specifier we have to ignore this solution
continue;
}
// Ensure the Graph we're inserting to exists in the dataset creating it if necessary
IGraph h;
Uri destUri = UriFactory.Create(graphUri);
if (graphs.ContainsKey(destUri))
{
h = graphs[destUri];
}
else
{
if (context.Data.HasGraph(destUri))
{
h = context.Data.GetModifiableGraph(destUri);
}
else
{
// insertedGraphs.Add(destUri);
h = new Graph();
h.BaseUri = destUri;
context.Data.AddGraph(h);
h = context.Data.GetModifiableGraph(destUri);
}
graphs.Add(destUri, h);
}
// Do the actual Insertions
foreach (IConstructTriplePattern p in gp.TriplePatterns.OfType <IConstructTriplePattern>())
{
try
{
Triple t = p.Construct(constructContext);
t = new Triple(t.Subject, t.Predicate, t.Object, destUri);
insertedTriples.Add(t);
}
catch (RdfQueryException)
{
// If we throw an error this means we couldn't construct a specific Triple
// so we continue anyway
}
}
h.Assert(insertedTriples);
}
catch (RdfQueryException)
{
// If we throw an error this means we couldn't construct for this solution so the
// solution is ignored for this Graph
}
}
}
catch (RdfQueryException)
{
// If we throw an error this means we couldn't construct for this solution so the
// solution is ignored for this graph
}
}
}
finally
{
// If the Dataset was set and an error occurred in doing the WHERE clause then
// we'll need to Reset the Active Graph
if (datasetOk)
{
context.Data.ResetActiveGraph();
}
if (defGraphOk)
{
context.Data.ResetActiveGraph();
}
}
}
