/// <summary>
/// Builds a graph of rdf:type triples to restrict subsequent SPIN Constructors, Rules or Constraint checks evaluations
/// </summary>
/// <param name="resources"></param>
internal Uri CreateExecutionContext(IEnumerable <INode> resources)
{
Uri executionContextUri = null;
if (resources != null)
{
executionContextUri = RDFRuntime.NewTempGraphUri();
SparqlParameterizedString restrictionQuery;
IGraph resourceRestrictions = new ThreadSafeGraph();
resourceRestrictions.BaseUri = executionContextUri;
INode inputGraphNode = RDFUtil.CreateUriNode(executionContextUri);
foreach (INode resource in resources)
{
resourceRestrictions.Assert(inputGraphNode, RDFRuntime.PropertyExecutionRestrictedTo, resource);
}
Storage.SaveGraph(resourceRestrictions);
restrictionQuery = new SparqlParameterizedString(SparqlTemplates.SetExecutionContext);
restrictionQuery.SetUri("resourceRestriction", executionContextUri);
StringBuilder sb = new StringBuilder();
foreach (Resource graph in DefaultGraphs)
{
sb.AppendLine("USING <" + graph.Uri.ToString() + ">");
}
restrictionQuery.CommandText = restrictionQuery.CommandText.Replace("@USING_DEFAULT", sb.ToString());
Storage.Update(restrictionQuery.ToString());
}
return(executionContextUri);
}
// TODO Replace IEnumerable<IUpdate> with a SparqlUpdateCommandSet
/// <summary>
/// TODO find a way to compile the global changes so ExecutionContexts can be set globally for Rules processing or Constraints checking.
/// </summary>
/// <param name="spinUpdateCommandSet"></param>
internal IGraph ExecuteUpdate(IEnumerable <IUpdate> spinUpdateCommandSet)
{
QueryMode currentQueryMode = QueryExecutionMode;
Uri currentExecutionGraphUri = RDFRuntime.NewTempGraphUri();
IGraph remoteChanges = new ThreadSafeGraph();
remoteChanges.BaseUri = currentExecutionGraphUri;
try
{
foreach (IUpdate update in spinUpdateCommandSet)
{
if (update != null)
{
UpdateInternal(update, currentExecutionGraphUri);
}
}
Storage.LoadGraph(remoteChanges, currentExecutionGraphUri);
List <Resource> newTypes = new List <Resource>();
foreach (Triple t in remoteChanges.Triples)
{
if (RDFUtil.sameTerm(RDF.PropertyType, t.Predicate))
{
// if remoteChanges contains an already checked rdf:type triple that means we have a infinite loop case in the SPIN processing pipeline so we stop execution
if (_loopPreventionChecks.Contains(t))
{
// TODO document better the exception cause
throw new SpinException("Infinite loop encountered. Execution is canceled");
}
_loopPreventionChecks.Add(t);
newTypes.Add(AsResource(t.Object));
}
else if (RDFUtil.sameTerm(RDFRuntime.PropertyHasChanged, t.Predicate))
{
// mark the resource as updated for the next global CheckConstraints or Apply rules
_changedResources.Add(t.Object);
}
else if (RDFUtil.sameTerm(RDFRuntime.PropertyResets, t.Predicate))
{
// TODO log the property resets for filtering pattern extensions in the subsequent SPARQL execution
}
}
CurrentExecutionContext = currentExecutionGraphUri;
// run the constructors
remoteChanges.Assert(this.RunConstructors(newTypes).Triples);
}
catch (Exception any)
{
// for cleanliness sake on exception cases
foreach (Uri graphUri in Configuration.GetTriplesRemovalsGraphs().Union(Configuration.GetTriplesAdditionsGraphs()))
{
Storage.DeleteGraph(graphUri);
}
throw new Exception("", any);
}
finally
{
Storage.DeleteGraph(currentExecutionGraphUri);
_queryExecutionMode = currentQueryMode;
ResetExecutionContext();
}
return(remoteChanges);
}
