public static EntityQuad ToEntityQuad(this VDS.RDF.Triple triple, EntityId id)
{
return(new EntityQuad(
id,
triple.Subject.ToNode(id),
triple.Predicate.ToNode(id),
triple.Object.ToNode(id),
Node.ForUri(triple.GraphUri)));
}
/// <summary>
/// Returns whether the Store contains the given Triple within the Query Triples
/// </summary>
/// <param name="t">Triple to search for</param>
/// <returns></returns>
public bool Contains(Triple t)
{
return(this._graphs.Any(g => g.Triples.Contains(t)));
}
/// <summary>
/// Gets whether the collection contains the given Triple
/// </summary>
/// <param name="t">Triple</param>
/// <returns></returns>
public override bool Contains(Triple t)
{
return(this._triples.Contains(t));
}
/// <summary>
/// Adds a triple to the collection
/// </summary>
/// <param name="t">Triple</param>
/// <returns></returns>
protected internal override bool Add(Triple t)
{
return(this._triples.Add(t));
}
internal void AddRemovedTriple(Triple t)
{
_removedTriples.Add(t);
}
/// <summary>
/// Returns whether the Store contains the given Triple within the Query Triples.
/// </summary>
/// <param name="t">Triple to search for.</param>
/// <returns></returns>
public bool Contains(Triple t)
{
return(_graphs.Any(g => g.ContainsTriple(t)));
}
/// <summary>
/// Adds a Triple to the base collection
/// </summary>
/// <param name="t">Triple to add</param>
protected internal override bool Add(Triple t)
{
return(this._baseCollection.Add(t));
}
/// <summary>
/// Indexes a Triple.
/// </summary>
/// <param name="t">Triple.</param>
private void Index(Triple t)
{
Index(t.Subject, t, _s, _sHash, _sComparer);
Index(t.Predicate, t, _p, _pHash, _pComparer);
Index(t.Object, t, _o, _oHash, _oComparer);
}
/// <summary>
/// Uses a series of Rules to attempt to generate a mapping without the need for brute force guessing.
/// </summary>
/// <param name="subgraph">1st Graph.</param>
/// <param name="parent">2nd Graph.</param>
/// <param name="subNodes">1st Graph Node classification.</param>
/// <param name="parentNodes">2nd Graph Node classification.</param>
/// <param name="subDegrees">1st Graph Degree classification.</param>
/// <param name="parentDegrees">2nd Graph Degree classification.</param>
/// <returns></returns>
private bool TryRulesBasedMapping(IGraph subgraph, IGraph parent, Dictionary <INode, int> subNodes, Dictionary <INode, int> parentNodes, Dictionary <int, int> subDegrees, Dictionary <int, int> parentDegrees)
{
// Start with new lists and dictionaries each time in case we get reused
_unbound = new List <INode>();
_bound = new List <INode>();
_mapping = new Dictionary <INode, INode>();
_subTriples = new List <Triple>();
// Initialise the Source Triples list
_subTriples.AddRange(from t in subgraph.Triples
where !t.IsGroundTriple
select t);
// First thing consider the trivial mapping
Dictionary <INode, INode> trivialMapping = new Dictionary <INode, INode>();
foreach (INode n in subNodes.Keys)
{
trivialMapping.Add(n, n);
}
List <Triple> targets = new List <Triple>(_parentTriples);
if (_subTriples.All(t => targets.Remove(t.MapTriple(parent, trivialMapping))))
{
_mapping = trivialMapping;
return(true);
}
// Initialise the Unbound list
_unbound = (from n in parentNodes.Keys
select n).ToList();
// Map single use Nodes first to reduce the size of the overall mapping
foreach (KeyValuePair <INode, int> pair in subNodes.Where(p => p.Value == 1))
{
// Find the Triple we need to map
Triple toMap = (from t in _subTriples
where t.Involves(pair.Key)
select t).First();
foreach (INode n in _unbound.Where(n => parentNodes[n] == pair.Value))
{
// See if this Mapping works
_mapping.Add(pair.Key, n);
if (_parentTriples.Remove(toMap.MapTriple(parent, _mapping)))
{
_subTriples.Remove(toMap);
_bound.Add(n);
break;
}
_mapping.Remove(pair.Key);
}
// If we couldn't map a single use Node then it's not a sub-graph
if (!_mapping.ContainsKey(pair.Key))
{
return(false);
}
else
{
// Otherwise we can mark that Node as Bound
_unbound.Remove(_mapping[pair.Key]);
}
}
// If all the Nodes were used only once and we mapped them all then it's a sub-graph
if (_parentTriples.Count == 0)
{
return(true);
}
// Map any Nodes of unique degree next
foreach (KeyValuePair <int, int> degreeClass in subDegrees)
{
if (degreeClass.Key > 1 && degreeClass.Value == 1)
{
// There is a Node of degree greater than 1 than has a unique degree
// i.e. there is only one Node with this degree so there can only ever be one
// possible mapping for this Node
INode x = subNodes.FirstOrDefault(p => p.Value == degreeClass.Key).Key;
INode y = parentNodes.FirstOrDefault(p => p.Value == degreeClass.Key).Key;
// If either of these return null then the Graphs can't be equal
if (x == null || y == null)
{
return(false);
}
// Add the Mapping
_mapping.Add(x, y);
_bound.Add(y);
_unbound.Remove(y);
}
}
// Work out which Nodes are paired up
// By this we mean any Nodes which appear with other Nodes in a Triple
// If multiple nodes appear together we can use this information to restrict
// the possible mappings we generate
List <MappingPair> subDependencies = new List <MappingPair>();
foreach (Triple t in _subTriples)
{
if (t.Subject.NodeType == NodeType.Blank && t.Predicate.NodeType == NodeType.Blank && t.Object.NodeType == NodeType.Blank)
{
throw new RdfException("GraphMatcher cannot compute mappings where a Triple is entirely composed of Blank Nodes");
}
if (t.Subject.NodeType == NodeType.Blank && t.Predicate.NodeType == NodeType.Blank)
{
if (!t.Subject.Equals(t.Predicate))
{
subDependencies.Add(new MappingPair(t.Subject, t.Predicate, TripleIndexType.SubjectPredicate));
}
}
else if (t.Subject.NodeType == NodeType.Blank && t.Object.NodeType == NodeType.Blank)
{
if (!t.Subject.Equals(t.Object))
{
subDependencies.Add(new MappingPair(t.Subject, t.Object, TripleIndexType.SubjectObject));
}
}
else if (t.Predicate.NodeType == NodeType.Blank && t.Object.NodeType == NodeType.Blank)
{
if (!t.Predicate.Equals(t.Object))
{
subDependencies.Add(new MappingPair(t.Predicate, t.Object, TripleIndexType.PredicateObject));
}
}
}
subDependencies = subDependencies.Distinct().ToList();
List <MappingPair> parentDependencies = new List <MappingPair>();
foreach (Triple t in _parentTriples)
{
if (t.Subject.NodeType == NodeType.Blank && t.Predicate.NodeType == NodeType.Blank && t.Object.NodeType == NodeType.Blank)
{
throw new RdfException("GraphMatcher cannot compute mappings where a Triple is entirely composed of Blank Nodes");
}
if (t.Subject.NodeType == NodeType.Blank && t.Predicate.NodeType == NodeType.Blank)
{
if (!t.Subject.Equals(t.Predicate))
{
parentDependencies.Add(new MappingPair(t.Subject, t.Predicate, TripleIndexType.SubjectPredicate));
}
}
else if (t.Subject.NodeType == NodeType.Blank && t.Object.NodeType == NodeType.Blank)
{
if (!t.Subject.Equals(t.Object))
{
parentDependencies.Add(new MappingPair(t.Subject, t.Object, TripleIndexType.SubjectObject));
}
}
else if (t.Predicate.NodeType == NodeType.Blank && t.Object.NodeType == NodeType.Blank)
{
if (!t.Predicate.Equals(t.Object))
{
parentDependencies.Add(new MappingPair(t.Predicate, t.Object, TripleIndexType.PredicateObject));
}
}
}
parentDependencies = parentDependencies.Distinct().ToList();
// Once we know of dependencies we can then map independent nodes
List <INode> subIndependents = (from n in subNodes.Keys
where !subDependencies.Any(p => p.Contains(n))
select n).ToList();
List <INode> parentIndependents = (from n in parentNodes.Keys
where !parentDependencies.Any(p => p.Contains(n))
select n).ToList();
// If the number of independent nodes in the sub-graph is greater than it cannot be a sub-graph
if (subIndependents.Count > parentIndependents.Count)
{
return(false);
}
// Try to map the independent nodes
foreach (INode x in subIndependents)
{
// They may already be mapped as they may be single use Triples
if (_mapping.ContainsKey(x))
{
continue;
}
List <Triple> xs = _subTriples.Where(t => t.Involves(x)).ToList();
foreach (INode y in parentIndependents)
{
if (subNodes[x] != parentNodes[y])
{
continue;
}
_mapping.Add(x, y);
// Test the mapping
List <Triple> ys = _parentTriples.Where(t => t.Involves(y)).ToList();
if (xs.All(t => ys.Remove(t.MapTriple(parent, _mapping))))
{
// This is a valid mapping
xs.ForEach(t => _parentTriples.Remove(t.MapTriple(parent, _mapping)));
xs.ForEach(t => _subTriples.Remove(t));
break;
}
_mapping.Remove(x);
}
// If we couldn't map an independent Node then we fail
if (!_mapping.ContainsKey(x))
{
return(false);
}
}
// Want to save our mapping so far here as if the mapping we produce using the dependency information
// is flawed then we'll have to attempt brute force
Dictionary <INode, INode> baseMapping = new Dictionary <INode, INode>(_mapping);
// Now we use the dependency information to try and find mappings
foreach (MappingPair dependency in subDependencies)
{
// If both dependent Nodes are already mapped we don't need to try mapping them again
if (_mapping.ContainsKey(dependency.X) && _mapping.ContainsKey(dependency.Y))
{
continue;
}
// Get all the Triples with this Pair in them
List <Triple> xs;
bool canonical = false;
switch (dependency.Type)
{
case TripleIndexType.SubjectPredicate:
xs = (from t in _subTriples
where t.Subject.Equals(dependency.X) && t.Predicate.Equals(dependency.Y)
select t).ToList();
if (xs.Count == 1)
{
canonical = ((from t in _subTriples
where t.Subject.NodeType == NodeType.Blank && t.Predicate.NodeType == NodeType.Blank && t.Object.Equals(xs[0].Object)
select t).Count() == 1);
}
break;
case TripleIndexType.SubjectObject:
xs = (from t in _subTriples
where t.Subject.Equals(dependency.X) && t.Object.Equals(dependency.Y)
select t).ToList();
if (xs.Count == 1)
{
canonical = ((from t in _subTriples
where t.Subject.NodeType == NodeType.Blank && t.Predicate.Equals(xs[0].Predicate) && t.Object.NodeType == NodeType.Blank
select t).Count() == 1);
}
break;
case TripleIndexType.PredicateObject:
xs = (from t in _subTriples
where t.Predicate.Equals(dependency.X) && t.Object.Equals(dependency.Y)
select t).ToList();
if (xs.Count == 1)
{
canonical = ((from t in _subTriples
where t.Subject.Equals(xs[0].Subject) && t.Predicate.NodeType == NodeType.Blank && t.Object.NodeType == NodeType.Blank
select t).Count() == 1);
}
break;
default:
// This means we've gone wrong somehow
throw new RdfException("Unknown exception occurred while trying to generate a Mapping between the two Graphs");
}
bool xbound = _mapping.ContainsKey(dependency.X);
bool ybound = _mapping.ContainsKey(dependency.Y);
// Look at all the possible Target Dependencies we could map to
foreach (MappingPair target in parentDependencies)
{
if (target.Type != dependency.Type)
{
continue;
}
// If one of the Nodes we're trying to map was already mapped then we can further restrict
// candidate mappings
if (xbound)
{
if (!target.X.Equals(_mapping[dependency.X]))
{
continue;
}
}
if (ybound)
{
if (!target.Y.Equals(_mapping[dependency.Y]))
{
continue;
}
}
// If the Nodes in the Target have already been used then we can discard this possible mapping
if (!xbound && _mapping.ContainsValue(target.X))
{
continue;
}
if (!ybound && _mapping.ContainsValue(target.Y))
{
continue;
}
// Get the Triples with the Target Pair in them
List <Triple> ys;
switch (target.Type)
{
case TripleIndexType.SubjectPredicate:
ys = (from t in _parentTriples
where t.Subject.Equals(target.X) && t.Predicate.Equals(target.Y)
select t).ToList();
break;
case TripleIndexType.SubjectObject:
ys = (from t in _parentTriples
where t.Subject.Equals(target.X) && t.Object.Equals(target.Y)
select t).ToList();
break;
case TripleIndexType.PredicateObject:
ys = (from t in _parentTriples
where t.Predicate.Equals(target.X) && t.Object.Equals(target.Y)
select t).ToList();
break;
default:
// This means we've gone wrong somehow
throw new RdfException("Unknown exception occurred while trying to generate a Mapping between the two Graphs");
}
// If the pairs are involved in a greater number of Triples in the sub-graph it cannot be a valid mapping
if (xs.Count > ys.Count)
{
continue;
}
// If all the Triples in xs can be removed from ys then this is a valid mapping
if (!xbound)
{
_mapping.Add(dependency.X, target.X);
}
if (!ybound)
{
_mapping.Add(dependency.Y, target.Y);
}
if (xs.All(t => ys.Remove(t.MapTriple(parent, _mapping))))
{
if (canonical)
{
// If this was the only possible mapping for this Pair then this is a canonical mapping
// and can go in the base mapping so if we have to brute force we have fewer possibles
// to try
if (!baseMapping.ContainsKey(dependency.X))
{
baseMapping.Add(dependency.X, target.X);
}
if (!baseMapping.ContainsKey(dependency.Y))
{
baseMapping.Add(dependency.Y, target.Y);
}
}
_bound.Add(target.X);
_bound.Add(target.Y);
_unbound.Remove(target.X);
_unbound.Remove(target.Y);
break;
}
else
{
if (!xbound)
{
_mapping.Remove(dependency.X);
}
if (!ybound)
{
_mapping.Remove(dependency.Y);
}
}
}
}
// If we've filled in the Mapping fully then the Graph is hopefully a sub-graph of the parent graph
if (_mapping.Count == subNodes.Count)
{
// Need to check we found a valid mapping
List <Triple> ys = new List <Triple>(_parentTriples);
if (_subTriples.All(t => ys.Remove(t.MapTriple(parent, _mapping))))
{
return(true);
}
else
{
_mapping = baseMapping;
return(TryBruteForceMapping(subgraph, parent, subNodes, parentNodes, subDependencies, parentDependencies));
}
}
else
{
return(TryBruteForceMapping(subgraph, parent, subNodes, parentNodes, subDependencies, parentDependencies));
}
}
/// <summary>
/// Compares two Triples
/// </summary>
/// <param name="x">Triple</param>
/// <param name="y">Triple</param>
/// <returns></returns>
public override int Compare(Triple x, Triple y)
{
return(_nodeComparer.Compare(x.Object, y.Object));
}
/// <summary>
/// Compares two Triples
/// </summary>
/// <param name="x">Triple</param>
/// <param name="y">Triple</param>
/// <returns></returns>
public override int Compare(Triple x, Triple y)
{
return(_nodeComparer.Compare(x.Predicate, y.Predicate));
}
/// <summary>
/// Gets whether a given Triple exists in this Graph.
/// </summary>
/// <param name="t">Triple to test.</param>
/// <returns></returns>
public virtual bool ContainsTriple(Triple t)
{
return(_g.ContainsTriple(t));
}
/// <summary>
/// Retracts a Triple from the Graph.
/// </summary>
/// <param name="t">Triple.</param>
public virtual bool Retract(Triple t)
{
return(_g.Retract(t));
}
/// <summary>
/// Asserts a Triple in the Graph.
/// </summary>
/// <param name="t">Triple.</param>
public virtual bool Assert(Triple t)
{
return(_g.Assert(t.CopyTriple(_g)));
}
/// <summary>
/// Unindexes a triple.
/// </summary>
/// <param name="t">Triple.</param>
private void Unindex(Triple t)
{
Unindex(t.Subject, t, _s);
Unindex(t.Predicate, t, _p);
Unindex(t.Object, t, _o);
}
/// <summary>
/// Checks whether the collection contains a given Triple.
/// </summary>
/// <param name="t">Triple.</param>
/// <returns></returns>
public override bool Contains(Triple t)
{
return(_triples.ContainsKey(t));
}
/// <summary>
/// Copies a Triple from one Graph to another
/// </summary>
/// <param name="t">Triple to copy</param>
/// <param name="target">Graph to copy to</param>
/// <returns></returns>
public static Triple CopyTriple(Triple t, IGraph target)
{
return(CopyTriple(t, target, false));
}
/// <summary>
/// Deletes a Triple from the base collection
/// </summary>
/// <param name="t">Triple to delete</param>
protected internal override bool Delete(Triple t)
{
return(this._baseCollection.Delete(t));
}
/// <summary>
/// Creates a new set of Triple Event Arguments for the given Triple
/// </summary>
/// <param name="t">Triple</param>
/// <param name="g">Graph the Triple Event occurred in</param>
public TripleEventArgs(Triple t, IGraph g)
: base()
{
this._t = t;
this._g = g;
}
/// <summary>
/// Checks whether the union contains this Triple in any of the collections it comprises
/// </summary>
/// <param name="t">Triple to test</param>
/// <returns></returns>
public override bool Contains(Triple t)
{
return(this._collections.Any(c => c.Contains(t)));
}
/// <summary>
/// Creates a new set of Triple Event Arguments for the given Triple
/// </summary>
/// <param name="t">Triple</param>
/// <param name="g">Graph the Triple Event occurred in</param>
/// <param name="asserted">Was the Triple Asserted (if not then it was Retracted)</param>
public TripleEventArgs(Triple t, IGraph g, bool asserted)
: this(t, g)
{
this._added = asserted;
}
/// <summary>
/// Deletes a triple from the collection
/// </summary>
/// <param name="t">Triple</param>
/// <returns></returns>
protected internal override bool Delete(Triple t)
{
return(this._triples.Delete(t));
}
internal void AddAddedTriple(Triple t)
{
_addedTriples.Add(t);
}
