/// <summary> /// Constructs a Node based on this Pattern for the given Set /// </summary> /// <param name="context">Construct Context</param> /// <returns></returns> protected internal abstract INode Construct(ConstructContext context);
/// <summary>
/// Evaluates the Command in the given Context
/// </summary>
/// <param name="context">Evaluation Context</param>
public override void Evaluate(SparqlUpdateEvaluationContext context)
{
//Split the Pattern into the set of Graph Patterns
List<GraphPattern> patterns = new List<GraphPattern>();
if (this._pattern.IsGraph)
{
patterns.Add(this._pattern);
}
else if (this._pattern.TriplePatterns.Count > 0 || this._pattern.HasChildGraphPatterns)
{
if (this._pattern.TriplePatterns.Count > 0)
{
patterns.Add(new GraphPattern());
this._pattern.TriplePatterns.ForEach(tp => patterns[0].AddTriplePattern(tp));
}
this._pattern.ChildGraphPatterns.ForEach(gp => patterns.Add(gp));
}
else
{
//If no Triple Patterns and No Child Graph Patterns nothing to do
return;
}
foreach (GraphPattern pattern in patterns)
{
if (!this.IsValidDataPattern(pattern, false)) throw new SparqlUpdateException("Cannot evaluate a INSERT DATA command where any of the Triple Patterns are not concrete triples (variables are not permitted) or any of the GRAPH clauses have nested Graph Patterns");
//Get the Target Graph
IGraph target;
Uri graphUri;
if (pattern.IsGraph)
{
switch (pattern.GraphSpecifier.TokenType)
{
case Token.QNAME:
throw new NotSupportedException("Graph Specifiers as QNames for INSERT DATA Commands are not supported - please specify an absolute URI instead");
case Token.URI:
graphUri = UriFactory.Create(pattern.GraphSpecifier.Value);
break;
default:
throw new SparqlUpdateException("Cannot evaluate an INSERT DATA Command as the Graph Specifier is not a QName/URI");
}
}
else
{
graphUri = null;
}
if (context.Data.HasGraph(graphUri))
{
target = context.Data.GetModifiableGraph(graphUri);
}
else
{
//If the Graph does not exist then it must be created
target = new Graph();
target.BaseUri = graphUri;
context.Data.AddGraph(target);
}
//Insert the actual Triples
INode subj, pred, obj;
ConstructContext constructContext = new ConstructContext(target, null, true);
foreach (IConstructTriplePattern p in pattern.TriplePatterns.OfType<IConstructTriplePattern>())
{
subj = p.Subject.Construct(constructContext);
pred = p.Predicate.Construct(constructContext);
obj = p.Object.Construct(constructContext);
target.Assert(new Triple(subj, pred, obj));
}
}
}
/// <summary>
/// Constructs a Node based on the given Set
/// </summary>
/// <param name="context">Construct Context</param>
protected internal override INode Construct(ConstructContext context)
{
return context.GetNode(this._node);
}
/// <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 (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 queryContext.OutputMultiset.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:
if (s.ContainsVariable(gp.GraphSpecifier.Value))
{
INode temp = s[gp.GraphSpecifier.Value.Substring(1)];
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>
/// Constructs a Triple from a Set based on this Triple Pattern
/// </summary>
/// <param name="context">Construct Context</param>
/// <returns></returns>
public Triple Construct(ConstructContext context)
{
return new Triple(Tools.CopyNode(this._subj.Construct(context), context.Graph), Tools.CopyNode(this._pred.Construct(context), context.Graph), Tools.CopyNode(this._obj.Construct(context), context.Graph));
}
/// <summary>
/// Constructs a Node based on the given Set
/// </summary>
/// <param name="context">Construct Context</param>
/// <returns>The Node which is bound to this Variable in this Solution</returns>
protected internal override INode Construct(ConstructContext context)
{
INode value = context.Set[this._varname];
if (value == null) throw new RdfQueryException("Unable to construct a Value for this Variable for this solution as it is bound to a null");
switch (value.NodeType)
{
case NodeType.Blank:
if (!context.PreserveBlankNodes && value.GraphUri != null)
{
//Rename Blank Node based on the Graph Uri Hash Code
int hash = value.GraphUri.GetEnhancedHashCode();
if (hash >= 0)
{
return new BlankNode(context.Graph, ((IBlankNode)value).InternalID + "-" + value.GraphUri.GetEnhancedHashCode());
}
else
{
return new BlankNode(context.Graph, ((IBlankNode)value).InternalID + hash);
}
}
else
{
return new BlankNode(context.Graph, ((IBlankNode)value).InternalID);
}
default:
return context.GetNode(value);
}
}
/// <summary>
/// Processes a DELETE DATA command
/// </summary>
/// <param name="cmd">DELETE Data Command</param>
public void ProcessDeleteDataCommand(DeleteDataCommand cmd)
{
if (this._manager is IUpdateableGenericIOManager)
{
((IUpdateableGenericIOManager)this._manager).Update(cmd.ToString());
}
else
{
//Check IO Behaviour
//For a delete we either need the ability to Update Delete Triples or to Overwrite Graphs
//Firstly check behaviour persuant to default graph if applicable
if (cmd.DataPattern.TriplePatterns.OfType<IConstructTriplePattern>().Any())
{
//Must support notion of default graph
if ((this._manager.IOBehaviour & IOBehaviour.HasDefaultGraph) == 0) throw new SparqlUpdateException("The underlying store does not support the notion of an explicit unnamed Default Graph required to process this command");
//Must allow either OverwriteDefault or CanUpdateDeleteTriples
if ((this._manager.IOBehaviour & IOBehaviour.CanUpdateDeleteTriples) == 0 && (this._manager.IOBehaviour & IOBehaviour.OverwriteDefault) == 0) throw new SparqlUpdateException("The underlying store does not support the required IO Behaviour to implement this command");
}
//Then check behaviour persuant to named graphs if applicable
if (cmd.DataPattern.HasChildGraphPatterns)
{
//Must support named graphs
if ((this._manager.IOBehaviour & IOBehaviour.HasNamedGraphs) == 0) throw new SparqlUpdateException("The underlying store does not support the notion of named graphs required to process this command");
//Must allow either CanUpdateDeleteTriples or OverwriteNamed
if ((this._manager.IOBehaviour & IOBehaviour.CanUpdateDeleteTriples) == 0 && (this._manager.IOBehaviour & IOBehaviour.OverwriteNamed) == 0) throw new SparqlUpdateException("The underlying store does not support the required IO Behaviour to implement this command");
}
//Split the Pattern into the set of Graph Patterns
List<GraphPattern> patterns = new List<GraphPattern>();
if (cmd.DataPattern.IsGraph)
{
patterns.Add(cmd.DataPattern);
}
else if (cmd.DataPattern.TriplePatterns.Count > 0 || cmd.DataPattern.HasChildGraphPatterns)
{
if (cmd.DataPattern.TriplePatterns.Count > 0)
{
patterns.Add(new GraphPattern());
cmd.DataPattern.TriplePatterns.ForEach(tp => patterns[0].AddTriplePattern(tp));
}
cmd.DataPattern.ChildGraphPatterns.ForEach(gp => patterns.Add(gp));
}
else
{
//If no Triple Patterns and No Child Graph Patterns nothing to do
return;
}
foreach (GraphPattern pattern in patterns)
{
if (!this.IsValidDataPattern(pattern, false)) throw new SparqlUpdateException("Cannot evaluate a DELETE DATA command where any of the Triple Patterns are not concrete triples - variables are not permitted");
Uri graphUri = null;
if (pattern.IsGraph)
{
switch (pattern.GraphSpecifier.TokenType)
{
case Token.QNAME:
throw new NotSupportedException("Graph Specifiers as QNames for DELETE DATA Commands are not supported - please specify an absolute URI instead");
case Token.URI:
graphUri = UriFactory.Create(pattern.GraphSpecifier.Value);
break;
default:
throw new SparqlUpdateException("Cannot evaluate an DELETE DATA Command as the Graph Specifier is not a QName/URI");
}
}
Graph g = new Graph();
if (!this._manager.UpdateSupported)
{
//If the Graph to be deleted from is empty then can skip as will have no affect on the Graph
this._manager.LoadGraph(g, graphUri);
if (g.IsEmpty) continue;
}
//Note that if the Manager supports Triple Level updates we won't load the Graph
//so we can't know whether it is empty or not and so can't skip the delete step
//Delete the actual Triples
INode subj, pred, obj;
ConstructContext context = new ConstructContext(g, null, true);
foreach (IConstructTriplePattern p in pattern.TriplePatterns.OfType<IConstructTriplePattern>())
{
subj = p.Subject.Construct(context);
pred = p.Predicate.Construct(context);
obj = p.Object.Construct(context);
if (!this._manager.UpdateSupported)
{
//If we don't support update then we'll have loaded the existing graph
//so we'll use this to remove the relevant triples to get to the intended state of
//the graph
g.Retract(new Triple(subj, pred, obj));
}
else
{
//If we do support update then we'll have an empty graph which we'll use to store
//up the set of triples to be removed
g.Assert(new Triple(subj, pred, obj));
}
}
if (this._manager.UpdateSupported)
{
this._manager.UpdateGraph(graphUri, Enumerable.Empty<Triple>(), g.Triples);
}
else
{
this._manager.SaveGraph(g);
}
}
}
}
/// <summary>
/// Processes an INSERT command
/// </summary>
/// <param name="cmd">Insert Command</param>
/// <remarks>
/// <para>
/// <strong>Note:</strong> The underlying manager must implement the <see cref="IQueryableGenericIOManager">IQueryableGenericIOManager</see> interface in order for INSERT commands to be processed
/// </para>
/// </remarks>
public void ProcessInsertCommand(InsertCommand cmd)
{
if (this._manager is IUpdateableGenericIOManager)
{
((IUpdateableGenericIOManager)this._manager).Update(cmd.ToString());
}
else
{
if (this._manager is IQueryableGenericIOManager)
{
//Check IO Behaviour
//For a insert we either need the ability to Update Add Triples or to Overwrite Graphs
//Firstly check behaviour persuant to default graph if applicable
if (cmd.InsertPattern.TriplePatterns.OfType<IConstructTriplePattern>().Any())
{
//Must support notion of default graph
if ((this._manager.IOBehaviour & IOBehaviour.HasDefaultGraph) == 0) throw new SparqlUpdateException("The underlying store does not support the notion of an explicit unnamed Default Graph required to process this command");
//Must allow either OverwriteDefault or CanUpdateAddTriples
if ((this._manager.IOBehaviour & IOBehaviour.CanUpdateAddTriples) == 0 && (this._manager.IOBehaviour & IOBehaviour.OverwriteDefault) == 0) throw new SparqlUpdateException("The underlying store does not support the required IO Behaviour to implement this command");
}
//Then check behaviour persuant to named graphs if applicable
if (cmd.InsertPattern.HasChildGraphPatterns)
{
//Must support named graphs
if ((this._manager.IOBehaviour & IOBehaviour.HasNamedGraphs) == 0) throw new SparqlUpdateException("The underlying store does not support the notion of named graphs required to process this command");
//Must allow either CanUpdateAddTriples or OverwriteNamed
if ((this._manager.IOBehaviour & IOBehaviour.CanUpdateAddTriples) == 0 && (this._manager.IOBehaviour & IOBehaviour.OverwriteNamed) == 0) throw new SparqlUpdateException("The underlying store does not support the required IO Behaviour to implement this command");
}
//First build and make the query to get a Result Set
String queryText = "SELECT * WHERE " + cmd.WherePattern.ToString();
SparqlQueryParser parser = new SparqlQueryParser();
SparqlQuery query = parser.ParseFromString(queryText);
if (cmd.GraphUri != null && !cmd.UsingUris.Any()) query.AddDefaultGraph(cmd.GraphUri);
foreach (Uri u in cmd.UsingUris)
{
query.AddDefaultGraph(u);
}
foreach (Uri u in cmd.UsingNamedUris)
{
query.AddNamedGraph(u);
}
Object results = ((IQueryableGenericIOManager)this._manager).Query(query.ToString());
if (results is SparqlResultSet)
{
//Now need to transform the Result Set back to a Multiset
Multiset mset = new Multiset((SparqlResultSet)results);
//Generate the Triples for each Solution
List<Triple> insertedTriples = new List<Triple>();
Dictionary<String, List<Triple>> insertedGraphTriples = new Dictionary<string, List<Triple>>();
foreach (ISet s in mset.Sets)
{
List<Triple> tempInsertedTriples = new List<Triple>();
try
{
ConstructContext context = new ConstructContext(null, s, true);
foreach (IConstructTriplePattern p in cmd.InsertPattern.TriplePatterns.OfType<IConstructTriplePattern>())
{
try
{
tempInsertedTriples.Add(p.Construct(context));
}
catch (RdfQueryException)
{
//If we get an error here then it means we couldn't construct a specific
//triple so we continue anyway
}
}
insertedTriples.AddRange(tempInsertedTriples);
}
catch (RdfQueryException)
{
//If we get an error here this means we couldn't construct for this solution so the
//solution is ignore for this graph
}
//Triples from GRAPH clauses
foreach (GraphPattern gp in cmd.InsertPattern.ChildGraphPatterns)
{
tempInsertedTriples.Clear();
try
{
String graphUri;
switch (gp.GraphSpecifier.TokenType)
{
case Token.URI:
graphUri = gp.GraphSpecifier.Value;
break;
case Token.VARIABLE:
if (s.ContainsVariable(gp.GraphSpecifier.Value))
{
INode temp = s[gp.GraphSpecifier.Value.Substring(1)];
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 (!insertedGraphTriples.ContainsKey(graphUri)) insertedGraphTriples.Add(graphUri, new List<Triple>());
ConstructContext context = new ConstructContext(null, s, true);
foreach (IConstructTriplePattern p in gp.TriplePatterns.OfType<IConstructTriplePattern>())
{
try
{
tempInsertedTriples.Add(p.Construct(context));
}
catch (RdfQueryException)
{
//If we get an error here then it means we couldn't construct a specific
//triple so we continue anyway
}
}
insertedGraphTriples[graphUri].AddRange(tempInsertedTriples);
}
catch (RdfQueryException)
{
//If we get an error here this means we couldn't construct for this solution so the
//solution is ignore for this graph
}
}
}
//Now decide how to apply the update
if (this._manager.UpdateSupported)
{
this._manager.UpdateGraph(cmd.GraphUri, insertedTriples, Enumerable.Empty<Triple>());
foreach (KeyValuePair<String, List<Triple>> graphInsertion in insertedGraphTriples)
{
this._manager.UpdateGraph(graphInsertion.Key, graphInsertion.Value, Enumerable.Empty<Triple>());
}
}
else
{
Graph g = new Graph();
this._manager.LoadGraph(g, cmd.GraphUri);
g.Assert(insertedTriples);
this._manager.SaveGraph(g);
foreach (KeyValuePair<String, List<Triple>> graphInsertion in insertedGraphTriples)
{
g = new Graph();
this._manager.LoadGraph(g, graphInsertion.Key);
g.Assert(graphInsertion.Value);
this._manager.SaveGraph(g);
}
}
}
else
{
throw new SparqlUpdateException("Cannot evaluate an INSERT Command as the underlying Store failed to answer the query for the WHERE portion of the command as expected");
}
}
else
{
throw new NotSupportedException("INSERT commands are not supported by this Update Processor as the manager for the underlying Store does not provide Query capabilities which are necessary to process this command");
}
}
}
/// <summary>
/// Processes an INSERT DATA command
/// </summary>
/// <param name="cmd">Insert Data Command</param>
public void ProcessInsertDataCommand(InsertDataCommand cmd)
{
if (this._manager is IUpdateableGenericIOManager)
{
((IUpdateableGenericIOManager)this._manager).Update(cmd.ToString());
}
else
{
//Check IO Behaviour
//For a insert we either need the ability to Update Delete Triples or to Overwrite Graphs
//Firstly check behaviour persuant to default graph if applicable
if (cmd.DataPattern.TriplePatterns.OfType<IConstructTriplePattern>().Any())
{
//Must support notion of default graph
if ((this._manager.IOBehaviour & IOBehaviour.HasDefaultGraph) == 0) throw new SparqlUpdateException("The underlying store does not support the notion of an explicit unnamed Default Graph required to process this command");
//Must allow either OverwriteDefault or CanUpdateAddTriples
if ((this._manager.IOBehaviour & IOBehaviour.CanUpdateAddTriples) == 0 && (this._manager.IOBehaviour & IOBehaviour.OverwriteDefault) == 0) throw new SparqlUpdateException("The underlying store does not support the required IO Behaviour to implement this command");
}
//Then check behaviour persuant to named graphs if applicable
if (cmd.DataPattern.HasChildGraphPatterns)
{
//Must support named graphs
if ((this._manager.IOBehaviour & IOBehaviour.HasNamedGraphs) == 0) throw new SparqlUpdateException("The underlying store does not support the notion of named graphs required to process this command");
//Must allow either CanUpdateAddTriples or OverwriteNamed
if ((this._manager.IOBehaviour & IOBehaviour.CanUpdateAddTriples) == 0 && (this._manager.IOBehaviour & IOBehaviour.OverwriteNamed) == 0) throw new SparqlUpdateException("The underlying store does not support the required IO Behaviour to implement this command");
}
//Split the Pattern into the set of Graph Patterns
List<GraphPattern> patterns = new List<GraphPattern>();
if (cmd.DataPattern.IsGraph)
{
patterns.Add(cmd.DataPattern);
}
else if (cmd.DataPattern.TriplePatterns.Count > 0 || cmd.DataPattern.HasChildGraphPatterns)
{
if (cmd.DataPattern.TriplePatterns.Count > 0)
{
patterns.Add(new GraphPattern());
cmd.DataPattern.TriplePatterns.ForEach(tp => patterns[0].AddTriplePattern(tp));
}
cmd.DataPattern.ChildGraphPatterns.ForEach(gp => patterns.Add(gp));
}
else
{
//If no Triple Patterns and No Child Graph Patterns nothing to do
return;
}
foreach (GraphPattern pattern in patterns)
{
if (!this.IsValidDataPattern(pattern, false)) throw new SparqlUpdateException("Cannot evaluate an INSERT DATA command where any of the Triple Patterns are not concrete triples - variables are not permitted");
Uri graphUri = null;
if (pattern.IsGraph)
{
switch (pattern.GraphSpecifier.TokenType)
{
case Token.QNAME:
throw new NotSupportedException("Graph Specifiers as QNames for INSERT DATA Commands are not supported - please specify an absolute URI instead");
case Token.URI:
graphUri = UriFactory.Create(pattern.GraphSpecifier.Value);
break;
default:
throw new SparqlUpdateException("Cannot evaluate an INSERT DATA Command as the Graph Specifier is not a QName/URI");
}
}
Graph g = new Graph();
if (!this._manager.UpdateSupported) this._manager.LoadGraph(g, graphUri);
//Insert the actual Triples
INode subj, pred, obj;
ConstructContext context = new ConstructContext(g, null, true);
foreach (IConstructTriplePattern p in pattern.TriplePatterns.OfType<IConstructTriplePattern>())
{
subj = p.Subject.Construct(context);
pred = p.Predicate.Construct(context);
obj = p.Object.Construct(context);
g.Assert(new Triple(subj, pred, obj));
}
if (this._manager.UpdateSupported)
{
this._manager.UpdateGraph(graphUri, g.Triples, Enumerable.Empty<Triple>());
}
else
{
this._manager.SaveGraph(g);
}
}
}
}
/// <summary>
/// Processes an INSERT/DELETE command
/// </summary>
/// <param name="cmd">Insert/Delete Command</param>
public void ProcessModifyCommand(ModifyCommand cmd)
{
if (this._manager is IUpdateableGenericIOManager)
{
((IUpdateableGenericIOManager)this._manager).Update(cmd.ToString());
}
else
{
if (this._manager is IQueryableGenericIOManager)
{
//First build and make the query to get a Result Set
String queryText = "SELECT * WHERE " + cmd.WherePattern.ToString();
SparqlQueryParser parser = new SparqlQueryParser();
SparqlQuery query = parser.ParseFromString(queryText);
if (cmd.GraphUri != null && !cmd.UsingUris.Any()) query.AddDefaultGraph(cmd.GraphUri);
foreach (Uri u in cmd.UsingUris)
{
query.AddDefaultGraph(u);
}
foreach (Uri u in cmd.UsingNamedUris)
{
query.AddNamedGraph(u);
}
Object results = ((IQueryableGenericIOManager)this._manager).Query(query.ToString());
if (results is SparqlResultSet)
{
//Now need to transform the Result Set back to a Multiset
Multiset mset = new Multiset((SparqlResultSet)results);
//Generate the Triples for each Solution
List<Triple> deletedTriples = new List<Triple>();
Dictionary<String, List<Triple>> deletedGraphTriples = new Dictionary<string, List<Triple>>();
foreach (Set s in mset.Sets)
{
List<Triple> tempDeletedTriples = new List<Triple>();
try
{
ConstructContext context = new ConstructContext(null, s, true);
foreach (IConstructTriplePattern p in cmd.DeletePattern.TriplePatterns.OfType<IConstructTriplePattern>())
{
try
{
tempDeletedTriples.Add(p.Construct(context));
}
catch (RdfQueryException)
{
//If we get an error here then it means we could not construct a specific
//triple so we continue anyway
}
}
deletedTriples.AddRange(tempDeletedTriples);
}
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
}
//Triples from GRAPH clauses
foreach (GraphPattern gp in cmd.DeletePattern.ChildGraphPatterns)
{
tempDeletedTriples.Clear();
try
{
String graphUri;
switch (gp.GraphSpecifier.TokenType)
{
case Token.URI:
graphUri = gp.GraphSpecifier.Value;
break;
case Token.VARIABLE:
if (s.ContainsVariable(gp.GraphSpecifier.Value))
{
INode temp = s[gp.GraphSpecifier.Value.Substring(1)];
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 (!deletedGraphTriples.ContainsKey(graphUri)) deletedGraphTriples.Add(graphUri, new List<Triple>());
ConstructContext context = new ConstructContext(null, s, true);
foreach (IConstructTriplePattern p in gp.TriplePatterns.OfType<IConstructTriplePattern>())
{
try
{
tempDeletedTriples.Add(p.Construct(context));
}
catch (RdfQueryException)
{
//If we throw an error this means we couldn't construct a specific
//triple so we continue anyway
}
}
deletedGraphTriples[graphUri].AddRange(tempDeletedTriples);
}
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
}
}
}
//Generate the Triples for each Solution
List<Triple> insertedTriples = new List<Triple>();
Dictionary<String, List<Triple>> insertedGraphTriples = new Dictionary<string, List<Triple>>();
foreach (Set s in mset.Sets)
{
List<Triple> tempInsertedTriples = new List<Triple>();
try
{
ConstructContext context = new ConstructContext(null, s, true);
foreach (IConstructTriplePattern p in cmd.InsertPattern.TriplePatterns.OfType<IConstructTriplePattern>())
{
try
{
tempInsertedTriples.Add(p.Construct(context));
}
catch (RdfQueryException)
{
//If we get an error here then it means we couldn't construct a specific
//triple so we continue anyway
}
}
insertedTriples.AddRange(tempInsertedTriples);
}
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
}
//Triples from GRAPH clauses
foreach (GraphPattern gp in cmd.InsertPattern.ChildGraphPatterns)
{
tempInsertedTriples.Clear();
try
{
String graphUri;
switch (gp.GraphSpecifier.TokenType)
{
case Token.URI:
graphUri = gp.GraphSpecifier.Value;
break;
case Token.VARIABLE:
if (s.ContainsVariable(gp.GraphSpecifier.Value))
{
INode temp = s[gp.GraphSpecifier.Value.Substring(1)];
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 (!insertedGraphTriples.ContainsKey(graphUri)) insertedGraphTriples.Add(graphUri, new List<Triple>());
ConstructContext context = new ConstructContext(null, s, true);
foreach (IConstructTriplePattern p in gp.TriplePatterns.OfType<IConstructTriplePattern>())
{
try
{
tempInsertedTriples.Add(p.Construct(context));
}
catch (RdfQueryException)
{
//If we get an error here it means we couldn't construct a specific
//triple so we continue anyway
}
}
insertedGraphTriples[graphUri].AddRange(tempInsertedTriples);
}
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
}
}
}
//Now decide how to apply the update
if (this._manager.UpdateSupported)
{
this._manager.UpdateGraph(cmd.GraphUri, insertedTriples, deletedTriples);
//We do these two operations sequentially even if in some cases they could be combined to ensure that the underlying
//Manager doesn't do any optimisations which would have the result of our updates not being properly applied
//e.g. ignoring Triples which are both asserted and retracted in one update
foreach (KeyValuePair<String, List<Triple>> graphDeletion in deletedGraphTriples)
{
this._manager.UpdateGraph(graphDeletion.Key, Enumerable.Empty<Triple>(), graphDeletion.Value);
}
foreach (KeyValuePair<String, List<Triple>> graphInsertion in insertedGraphTriples)
{
this._manager.UpdateGraph(graphInsertion.Key, graphInsertion.Value, Enumerable.Empty<Triple>());
}
}
else
{
Graph g = new Graph();
this._manager.LoadGraph(g, cmd.GraphUri);
g.Retract(deletedTriples);
this._manager.SaveGraph(g);
foreach (String graphUri in deletedGraphTriples.Keys.Concat(insertedGraphTriples.Keys).Distinct())
{
g = new Graph();
this._manager.LoadGraph(g, graphUri);
if (deletedGraphTriples.ContainsKey(graphUri)) g.Retract(deletedGraphTriples[graphUri]);
if (insertedGraphTriples.ContainsKey(graphUri)) g.Assert(insertedGraphTriples[graphUri]);
this._manager.SaveGraph(g);
}
}
}
else
{
throw new SparqlUpdateException("Cannot evaluate an INSERT/DELETE Command as the underlying Store failed to answer the query for the WHERE portion of the command as expected");
}
}
else
{
throw new NotSupportedException("INSERT/DELETE commands are not supported by this Update Processor as the manager for the underlying Store does not provide Query capabilities which are necessary to process this command");
}
}
}
/// <summary>
/// Processes an INSERT DATA command
/// </summary>
/// <param name="cmd">Insert Data Command</param>
public void ProcessInsertDataCommand(InsertDataCommand cmd)
{
if (this._manager is IUpdateableGenericIOManager)
{
((IUpdateableGenericIOManager)this._manager).Update(cmd.ToString());
}
else
{
//Split the Pattern into the set of Graph Patterns
List<GraphPattern> patterns = new List<GraphPattern>();
if (cmd.DataPattern.IsGraph)
{
patterns.Add(cmd.DataPattern);
}
else if (cmd.DataPattern.TriplePatterns.Count > 0 || cmd.DataPattern.HasChildGraphPatterns)
{
if (cmd.DataPattern.TriplePatterns.Count > 0)
{
patterns.Add(new GraphPattern());
cmd.DataPattern.TriplePatterns.ForEach(tp => patterns[0].AddTriplePattern(tp));
}
cmd.DataPattern.ChildGraphPatterns.ForEach(gp => patterns.Add(gp));
}
else
{
//If no Triple Patterns and No Child Graph Patterns nothing to do
return;
}
foreach (GraphPattern pattern in patterns)
{
if (!this.IsValidDataPattern(pattern, false)) throw new SparqlUpdateException("Cannot evaluate an INSERT DATA command where any of the Triple Patterns are not concrete triples - variables are not permitted");
Uri graphUri = null;
if (pattern.IsGraph)
{
switch (pattern.GraphSpecifier.TokenType)
{
case Token.QNAME:
throw new NotImplementedException("Graph Specifiers as QNames for INSERT DATA Commands are not supported - please specify an absolute URI instead");
case Token.URI:
graphUri = new Uri(pattern.GraphSpecifier.Value);
break;
default:
throw new SparqlUpdateException("Cannot evaluate an INSERT DATA Command as the Graph Specifier is not a QName/URI");
}
}
Graph g = new Graph();
if (!this._manager.UpdateSupported) this._manager.LoadGraph(g, graphUri);
//Insert the actual Triples
INode subj, pred, obj;
ConstructContext context = new ConstructContext(g, null, true);
foreach (IConstructTriplePattern p in pattern.TriplePatterns.OfType<IConstructTriplePattern>())
{
subj = p.Subject.Construct(context);
pred = p.Predicate.Construct(context);
obj = p.Object.Construct(context);
g.Assert(new Triple(subj, pred, obj));
}
if (this._manager.UpdateSupported)
{
this._manager.UpdateGraph(graphUri, g.Triples, Enumerable.Empty<Triple>());
}
else
{
this._manager.SaveGraph(g);
}
}
}
}
/// <summary>
/// Returns a Blank Node with a fixed ID scoped to whichever graph is provided
/// </summary>
/// <param name="context">Construct Context</param>
protected internal override INode Construct(ConstructContext context)
{
if (context.Graph != null)
{
IBlankNode b = context.Graph.GetBlankNode(this._id);
if (b != null)
{
return b;
}
else
{
return context.Graph.CreateBlankNode(this._id);
}
}
else
{
return new BlankNode(context.Graph, this._id);
}
}
/// <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 = this._wherePattern.ToAlgebra();
//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 (!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 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.UsingNamedUris)
{
query.AddNamedGraph(u);
}
SparqlEvaluationContext queryContext = new SparqlEvaluationContext(query, context.Data);
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 = where.Evaluate(queryContext);
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;
}
//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
//HashSet<Uri> insertedGraphs = new HashSet<Uri>();
IGraph g;
if (context.Data.HasGraph(this._graphUri))
{
g = context.Data.GetModifiableGraph(this._graphUri);
}
else
{
//insertedGraphs.Add(this._graphUri);
g = new Graph();
g.BaseUri = this._graphUri;
context.Data.AddGraph(g);
g = context.Data.GetModifiableGraph(this._graphUri);
}
//Insert the Triples for each Solution
foreach (Set s in queryContext.OutputMultiset.Sets)
{
List<Triple> insertedTriples = new List<Triple>();
//Triples from raw Triple Patterns
try
{
ConstructContext constructContext = new ConstructContext(g, s, true);
foreach (IConstructTriplePattern p in this._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);
}
catch (RdfQueryException)
{
//If we throw an error this means we couldn't construct for this solution so the
//solution is ignored for this graph
}
//Triples from GRAPH clauses
foreach (GraphPattern gp in this._insertPattern.ChildGraphPatterns)
{
insertedTriples.Clear();
try
{
String graphUri;
switch (gp.GraphSpecifier.TokenType)
{
case Token.URI:
graphUri = gp.GraphSpecifier.Value;
break;
case Token.VARIABLE:
if (s.ContainsVariable(gp.GraphSpecifier.Value))
{
INode temp = s[gp.GraphSpecifier.Value.Substring(1)];
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;
}
//Ensure the Graph we're inserting to exists in the dataset creating it if necessary
IGraph h;
Uri destUri = new Uri(graphUri);
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);
}
//Do the actual Insertions
ConstructContext constructContext = new ConstructContext(h, s, true);
foreach (IConstructTriplePattern p in gp.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
}
}
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
}
}
}
}
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();
}
}
