void AddRelation(Entity a, Entity b, Hashtable h, bool incself) {
ResSet r = (ResSet)h[a];
if (r == null) {
r = new ResSet();
h[a] = r;
if (incself) r.Add(a);
}
r.Add(b);
}
public static void FindMSG(SelectableSource store, Entity node, StatementSink msg) {
if (node.Uri != null) throw new ArgumentException("node must be anonymous");
ResSet nodesSeen = new ResSet();
ResSet nodesToAdd = new ResSet();
nodesToAdd.Add(node);
while (nodesToAdd.Count > 0) {
ResSet nodes = nodesToAdd;
nodesToAdd = new ResSet();
Sink sink = new Sink(msg, nodesToAdd);
foreach (Entity n in nodes) {
if (nodesSeen.Contains(n)) continue;
nodesSeen.Add(n);
store.Select(new Statement(n, null, null, null), sink);
store.Select(new Statement(null, n, null, null), sink);
store.Select(new Statement(null, null, n, null), sink);
}
}
}
private static bool MakeLeanMSG3(Store msg, ResSet predicates, StatementSink removed,
ResSet nodesremoved, SyncPath path) {
// The variable path has to be expanded by including the statements
// connected to the variables on the frontier. Statements
// mentioning a variable node have already been considered.
// The target of each such statement can be considered fixed
// or variable. If a variable is considered fixed, the edge
// must exist in the MSG substituting the variables for their
// values. If it's variable, it has to have at least one
// match in the MSG but not as any of the variable nodes.
// If all targets are considered fixed (and have matches),
// then the variables so far (and their edges) can all be
// removed and no more processing needs to be done.
// There are (2^N)-1 other considerations. For each of those,
// the targets considered variables all become the new
// frontier, and this is repeated.
// First, get a list of edges from the frontier that we
// haven't considered yet.
ArrayList alledges = new ArrayList();
foreach (BNode b in path.FrontierVariables) {
// Make sure all edges are kept because even the ones
// to literals have to be removed when duplication is found.
foreach (Statement s in msg.Select(new Statement(b, null, null)))
alledges.Add(new Edge(true, b, s.Predicate, s.Object));
foreach (Statement s in msg.Select(new Statement(null, null, b)))
alledges.Add(new Edge(false, b, s.Predicate, s.Subject));
}
ArrayList newedges = new ArrayList();
ResSet alltargets = new ResSet();
ResSet fixabletargetsset = new ResSet(); // can be fixed
ResSet variabletargetsset = new ResSet(); // must be variable
foreach (Edge e in alledges) {
if (path.Path.ContainsKey(e)) continue;
path.Path[e] = e;
// This checks if we can keep the target of this edge
// fixed, given the variable mappings we have so far.
bool isTargetFixable =
msg.Contains(e.AsStatement().Replace(path.Mapping));
// If the target of e is any of the following, we
// can check immediately if the edge is supported
// by the MSG under the variable mapping we have so far:
// a named node, literal, fixed node, or predicate
// a variable we've seen already
// If it's not supported, this path fails. If it is
// supported, we're done with this edge.
if (!(e.End is BNode)
|| path.FixedNodes.Contains(e.End)
|| predicates.Contains(e.End)
|| path.VariableNodes.Contains(e.End)) {
if (!isTargetFixable) return false;
continue; // this edge is supported, so we can continue
}
// The target of e is a new BNode.
// If this target is not fixable via this edge, it's
// not fixable at all.
if (!isTargetFixable) {
fixabletargetsset.Remove(e.End);
variabletargetsset.Add(e.End);
}
if (!alltargets.Contains(e.End)) {
alltargets.Add(e.End);
fixabletargetsset.Add(e.End);
}
newedges.Add(e);
}
// If all of the targets were fixable (trivially true also
// if there simple were no new edges/targets), then we've reached
// the end of this path. We can immediately remove
// the edges we've seen so far, under the variable mapping
// we've chosen.
if (variabletargetsset.Count == 0) {
foreach (Edge e in path.Path.Keys) {
Statement s = e.AsStatement();
msg.Remove(s);
if (removed != null) removed.Add(s);
}
foreach (Entity e in path.Mapping.Keys)
nodesremoved.Add(e);
return true;
}
// At this point, at least one target must be a variable
// and we'll have to expand the path in that direction.
// We might want to permute through the ways we can
// take fixable nodes as either fixed or variable, but
// we'll be greedy and assume everything fixable is
// fixed and everything else is a variable.
path.FixedNodes.AddRange(fixabletargetsset);
path.VariableNodes.AddRange(variabletargetsset);
// But we need to look at all the ways each variable target
// can be mapped to a new value, which means intersecting
// the possible matches for each relevant edge.
Entity[] variables = variabletargetsset.ToEntityArray();
ResSet[] values = new ResSet[variables.Length];
Entity[][] values_array = new Entity[variables.Length][];
int[] choices = new int[variables.Length];
for (int i = 0; i < variables.Length; i++) {
foreach (Edge e in newedges) {
if (e.End != variables[i]) continue;
// Get the possible values this edge allows
Resource[] vr;
if (e.Direction)
vr = msg.SelectObjects((Entity)path.Mapping[e.Start], e.Predicate);
else
vr = msg.SelectSubjects(e.Predicate, (Entity)path.Mapping[e.Start]);
// Filter out literals and any variables
// on the path! The two paths can't intersect
// except at fixed nodes.
ResSet v = new ResSet();
foreach (Resource r in vr) {
if (r is Literal) continue;
if (path.Mapping.ContainsKey(r)) continue;
v.Add(r);
}
// Intersect these with the values we have already.
if (values[i] == null)
values[i] = v;
else
values[i].RetainAll(v);
// If no values are available for this variable,
// we're totally done.
if (values[i].Count == 0) return false;
}
choices[i] = values[i].Count;
values_array[i] = values[i].ToEntityArray();
}
// Now we have to permute through the choice of values.
// Make an array of the number of choices for each variable.
Permutation p = new Permutation(choices);
int[] pstate;
while ((pstate = p.Next()) != null) {
SyncPath newpath = new SyncPath();
newpath.FixedNodes.AddRange(path.FixedNodes);
newpath.VariableNodes.AddRange(path.VariableNodes);
newpath.Mapping = (Hashtable)path.Mapping.Clone();
newpath.Path = (Hashtable)path.Path.Clone();
newpath.FrontierVariables = variabletargetsset;
for (int i = 0; i < variables.Length; i++) {
Entity value = values_array[i][pstate[i]];
newpath.Mapping[variables[i]] = value;
newpath.FixedNodes.Add(value);
}
if (MakeLeanMSG3(msg, predicates, removed,
nodesremoved, newpath)) return true;
}
return false;
}
private static void MakeLeanMSG2(Store msg, ResSet predicates, StatementSink removed,
ResSet nodesremoved, BNode startingnode) {
// Find every pair of two distinct outgoing edges from startingnode
// with the same predicate, targeting entities only.
MultiMap edges = new MultiMap();
foreach (Statement s in msg.Select(new Statement(startingnode, null, null)))
if (s.Object is Entity)
edges.Put(new Edge(true, startingnode, s.Predicate, null), s.Object);
foreach (Statement s in msg.Select(new Statement(null, null, startingnode)))
edges.Put(new Edge(false, startingnode, s.Predicate, null), s.Subject);
foreach (Edge e in edges.Keys) {
// Make sure we have a distinct set of targets.
ResSet targets_set = new ResSet();
foreach (Entity r in edges.Get(e))
targets_set.Add(r);
if (targets_set.Count == 1) continue;
IList targets = targets_set.ToEntityArray();
// Take every pair of targets, provided
// one is a bnode that can be a variable.
for (int i = 0; i < targets.Count; i++) {
if (!(targets[i] is BNode) || predicates.Contains((BNode)targets[i])) continue;
if (nodesremoved.Contains((BNode)targets[i])) continue;
for (int j = 0; j < targets.Count; j++) {
if (i == j) continue;
// Create a new synchronous-path object.
SyncPath p = new SyncPath();
p.FixedNodes.Add((Resource)targets[j]);
p.FrontierVariables.Add((Resource)targets[i]);
p.Mapping[targets[i]] = targets[j];
p.Path[new Edge(e.Direction, e.Start, e.Predicate, (BNode)targets[i])] = p.Path;
if (MakeLeanMSG3(msg, predicates, removed, nodesremoved, p))
break; // the target was removed
}
}
}
}
private static void MakeLeanMSG(Store msg, ICollection bnodecollection, StatementSink removed) {
// To make any graph lean, we try to eliminate duplicate
// paths through the graph, where duplicate means we
// take some subset of the bnodes and call them variables,
// and we relabel them as other bnodes from the remaining
// set (the fixed nodes). But there are 2^N subsets of bnodes
// we could choose as variables (N=number of bnodes), so we can't
// reasonably iterate through them.
// I'll make a simplifying assumption that bnode predicates
// in the graph will be considered always fixed.
// This lets us view the graph as actually a graph (with
// nodes and edges), and then we can make the observation that
// if variable node V is part of a subgraph that can be removed,
// if V directly connects to fixed node F via an edge labeled P,
// then F must connect to a fixed node G via an edge also
// labeled P. That is, we can start our search looking for
// nodes that project two edges with the same label.
// Also, we only want to consider contiguous 'paths' -- subsets
// of the bnodes connected only through those nodes --
// to see if there is another path in the MSG if we
// map bnodes in the first path to nodes in the MSG.
// So the strategy is to start at each node in the graph
// and consider it fixed. If it has two outgoing
// edges with the same property and one terminates on a
// bnode, this is the beginning of a possible pair
// of redundant paths (the one with the bnode being
// eliminable).
// However, the path with the bnode
// has to be incremented with all of that bnode's
// outgoing edges. The other path has to be
// incremented in parallel, following the same predicates
// to other nodes. If that can't be done, then these
// paths are not duplicates. If the parallel predicates
// terminate on the very same nodes, the bnode and its edges can
// be removed.
// From there, each of the nodes the bnode edges terminate on,
// besides the initial node, can be considered fixed or
// a variable. If it's a variable it might be able to have
// one of many possible values, but then the path has to
// be expanded to include all of the outgoing edges for this
// variable.
// Ok, here we go.
// If there is only one bnode in the MSG, then
// there are no subgraphs to check. That's nice.
if (bnodecollection.Count == 1) return;
// Remember which bnodes have been removed in
// due course.
ResSet nodesremoved = new ResSet();
// Remember which nodes are predicates and can't
// be considered variable.
ResSet predicates = new ResSet();
foreach (Statement s in msg.Select(Statement.All))
predicates.Add(s.Predicate);
// Start with each bnode to consider fixed.
foreach (BNode b in bnodecollection) {
if (nodesremoved.Contains(b)) continue;
MakeLeanMSG2(msg, predicates, removed, nodesremoved, b);
}
}
public void Select(SelectFilter filter, StatementSink sink) {
if (filter.Predicates == null || filter.LiteralFilters != null) {
data.Select(filter, sink);
return;
}
ResSet remainingPredicates = new ResSet();
Entity[] subjects = filter.Subjects;
Entity[] predicates = filter.Predicates;
Resource[] objects = filter.Objects;
Entity[] metas = filter.Metas;
foreach (Entity p in predicates) {
if (p == type) {
if (objects != null) {
// Do the subjects have any of the types listed in the objects,
// or what things have those types?
// Expand objects by the subclass closure of the objects
data.Select(new SelectFilter(subjects, new Entity[] { p }, GetClosure(objects, subclasses), metas), sink);
// Process domains and ranges.
ResSet dom = new ResSet(), ran = new ResSet();
Hashtable domPropToType = new Hashtable();
Hashtable ranPropToType = new Hashtable();
foreach (Entity e in objects) {
Entity[] dc = GetClosure((ResSet)domainof[e], subprops);
if (dc != null)
foreach (Entity c in dc) {
dom.Add(c);
AddRelation(c, e, domPropToType, false);
}
dc = GetClosure((ResSet)rangeof[e], subprops);
if (dc != null)
foreach (Entity c in dc) {
ran.Add(c);
AddRelation(c, e, ranPropToType, false);
}
}
// If it's in the domain of any of these properties,
// we know its type.
if (subjects != null) {
if (dom.Count > 0) data.Select(new SelectFilter(subjects, dom.ToEntityArray(), null, metas), new ExpandDomRan(0, domPropToType, sink));
if (ran.Count > 0) data.Select(new SelectFilter(null, ran.ToEntityArray(), subjects, metas), new ExpandDomRan(1, ranPropToType, sink));
}
} else if (subjects != null) {
// What types do these subjects have?
// Expand the resulting types by the closure of their superclasses
data.Select(new SelectFilter(subjects, new Entity[] { p }, objects, metas), new Expand(superclasses, sink));
// Use domains and ranges to get type info
data.Select(new SelectFilter(subjects, null, null, metas), new Expand3(0, domains, superclasses, sink));
data.Select(new SelectFilter(null, null, subjects, metas), new Expand3(1, ranges, superclasses, sink));
} else {
// What has type what? We won't answer that question.
data.Select(filter, sink);
}
} else if ((p == subClassOf || p == subPropertyOf)
&& (metas == null || metas[0] == Statement.DefaultMeta)) {
Hashtable supers = (p == subClassOf) ? superclasses : superprops;
Hashtable subs = (p == subClassOf) ? subclasses : subprops;
if (subjects != null && objects != null) {
// Expand objects by the subs closure of the objects.
data.Select(new SelectFilter(subjects, new Entity[] { p }, GetClosure(objects, subs), metas), sink);
} else if (subjects != null) {
// get all of the supers of all of the subjects
foreach (Entity s in subjects)
foreach (Entity o in GetClosure(new Entity[] { s }, supers))
sink.Add(new Statement(s, p, o));
} else if (objects != null) {
// get all of the subs of all of the objects
foreach (Resource o in objects) {
if (o is Literal) continue;
foreach (Entity s in GetClosure(new Entity[] { (Entity)o }, subs))
sink.Add(new Statement(s, p, (Entity)o));
}
} else {
// What is a subclass/property of what? We won't answer that.
data.Select(filter, sink);
}
} else {
remainingPredicates.Add(p);
}
}
if (remainingPredicates.Count > 0) {
// Also query the subproperties of any property
// being queried, but remember which subproperties
// came from which superproperties so we can map them
// back to the properties actually queried. The closures
// contain the queried properties themselves too.
ResSet qprops = new ResSet();
Hashtable propfrom = new Hashtable();
foreach (Entity p in remainingPredicates) {
foreach (Entity sp in GetClosure(new Entity[] { p }, subprops)) {
AddRelation(sp, p, propfrom, false);
qprops.Add(sp);
}
}
//data.Select(subjects, qprops.ToEntityArray(), objects, metas, new LiteralDTMap(ranges, new PredMap(propfrom, sink)));
SelectFilter sf = new SelectFilter(subjects, qprops.ToEntityArray(), objects, metas);
sf.LiteralFilters = filter.LiteralFilters;
sf.Limit = filter.Limit;
data.Select(sf, new PredMap(propfrom, sink));
}
}
static Entity[] GetClosure(Resource[] starts, Hashtable table) {
ResSet ret = new ResSet();
ResSet toadd = new ResSet(starts);
while (toadd.Count > 0) {
ResSet newadd = new ResSet();
foreach (Resource e in toadd) {
if (!(e is Entity)) continue;
if (ret.Contains(e)) continue;
ret.Add(e);
if (table.ContainsKey(e))
newadd.AddRange((ResSet)table[e]);
}
toadd.Clear();
toadd.AddRange(newadd);
}
return ret.ToEntityArray();
}
// The next few routines convert a set of axioms from a StatementSource
// into a data structure of use for the algorithm, with Sequents and things.
private static Hashtable RulesToCases(StatementSource rules)
{
Hashtable cases = new Hashtable();
MemoryStore rules_store = new MemoryStore(rules);
foreach (Statement p in rules_store) {
if (p.Meta == Statement.DefaultMeta) {
if (p.Predicate == entLOGIMPLIES && p.Object is Entity) {
MemoryStore body = new MemoryStore();
MemoryStore head = new MemoryStore();
rules_store.Select(new Statement(null, null, null, (Entity)p.Subject), new RemoveMeta(body));
rules_store.Select(new Statement(null, null, null, (Entity)p.Object), new RemoveMeta(head));
// Any variables in the head not bound in the body represent existentially closed bnodes.
// (Euler's OWL test case does this. Wish they had used bnodes instead of vars...)
ResSet bodyvars = new ResSet();
foreach (Statement b in body) {
if (b.Subject is Variable) bodyvars.Add(b.Subject);
if (b.Predicate is Variable) bodyvars.Add(b.Predicate);
if (b.Object is Variable) bodyvars.Add(b.Object);
}
foreach (Entity v in head.GetEntities()) {
if (v is Variable && !bodyvars.Contains(v))
head.Replace(v, new BNode(((Variable)v).LocalName));
}
// Replace (...) lists in the body that are tied to the subjects
// of user predicates with callArgs objects.
Hashtable callArgs = new Hashtable();
CollectCallArgs(body, callArgs);
// Rules can't have more than one statement in their
// consequent. The best we can do is break up
// the consequent into multiple rules. (Since all head
// variables are bound in body, it's equivalent...?)
foreach (Statement h in head)
AddSequent(cases, new Sequent(h, body.ToArray(), callArgs));
} else {
AddSequent(cases, new Sequent(p, new Statement[0], null));
}
}
}
return cases;
}
ResSet GetQueryRes(Statement s, int i, SemWeb.Query.QueryOptions options) {
ResSet ret = new ResSet();
Resource r = s.GetComponent(i);
if (r == null) return ret;
if (!(r is Variable)) ret.Add(r);
if (options.VariableKnownValues != null && r is Variable
#if !DOTNET2
&& options.VariableKnownValues.Contains((Variable)r)) {
static Entity[] GetClosure(Resource[] starts, Hashtable table, bool includeStarts) {
ResSet ret = new ResSet();
ResSet toadd = new ResSet(starts);
bool firstRound = true;
while (toadd.Count > 0) {
ResSet newadd = new ResSet();
foreach (Resource e in toadd) {
if (!(e is Entity)) continue;
if (ret.Contains(e)) continue;
if (!(firstRound && !includeStarts)) ret.Add(e);
if (table.ContainsKey(e))
newadd.AddRange((ResSet)table[e]);
}
toadd.Clear();
toadd.AddRange(newadd);
firstRound = false;
}
return ret.ToEntityArray();
}
public void Query(Statement[] graph, QueryOptions options, QueryResultSink sink) {
if (options.DistinguishedVariables != null && options.DistinguishedVariables.Count == 0)
throw new ArgumentException("options.DistinguishedVariables cannot be an empty list.");
StringBuilder query = new StringBuilder();
query.Append("SELECT ");
// Get a list of variables and map them to fresh names
#if !DOTNET2
Hashtable variableNames = new Hashtable();
#else
Dictionary<Variable,string> variableNames = new Dictionary<Variable,string>();
#endif
Hashtable variableNames2 = new Hashtable();
foreach (Statement s in graph) {
for (int j = 0; j < 3; j++) {
Variable v = s.GetComponent(j) as Variable;
if (v == null) continue;
if (variableNames.ContainsKey(v)) continue;
variableNames2["v" + variableNames.Count] = v;
variableNames[v] = "?v" + variableNames.Count;
}
}
// What variables will we select on?
ArrayList selectedVars = new ArrayList();
foreach (Variable v in
options.DistinguishedVariables != null
? options.DistinguishedVariables
: variableNames.Keys) {
if (!variableNames.ContainsKey(v)) continue; // in case distinguished variables list
// has more than what actually appears in query
if (selectedVars.Contains(v)) continue; // don't select more than once
query.Append(variableNames[v]);
query.Append(' ');
selectedVars.Add(v);
}
if (selectedVars.Count == 0) {
if (options.DistinguishedVariables == null)
throw new ArgumentException("There were no variables in the query.");
else
throw new ArgumentException("None of the variables in the query were distinguished.");
}
// Bnodes are not allowed here -- we can't query on them.
foreach (Statement s in graph) {
for (int j = 0; j < 3; j++) {
if (s.GetComponent(j) is BNode && !(s.GetComponent(j) is Variable)) {
Variable[] varArray = (Variable[])selectedVars.ToArray(typeof(Variable));
sink.Init(varArray);
sink.Finished();
return;
}
}
}
// Build the graph pattern.
query.Append("WHERE {\n");
ResSet firstVarUse = new ResSet();
foreach (Statement s in graph) {
for (int j = 0; j < 3; j++) {
Resource r = s.GetComponent(j);
query.Append(S(r, r is Variable && variableNames.ContainsKey((Variable)r) ? (string)variableNames[(Variable)r] : null));
query.Append(" ");
}
query.Append(" . \n");
if (options.VariableKnownValues != null) {
for (int j = 0; j < 3; j++) {
Resource r = s.GetComponent(j);
if (firstVarUse.Contains(r)) continue;
firstVarUse.Add(r);
if (r is Variable && variableNames.ContainsKey((Variable)r) &&
#if !DOTNET2
options.VariableKnownValues.Contains(r)
#else
options.VariableKnownValues.ContainsKey((Variable)r)
#endif
)
query.Append(SL(options.VariableKnownValues[(Variable)r], (string)variableNames[(Variable)r], true));
}
}
// And what about meta...?
}
query.Append("}");
if (options.Limit > 0) {
query.Append(" LIMIT ");
query.Append(options.Limit);
}
Load(query.ToString(), new QueryResultsWrapper(sink, variableNames2));
}
private bool Query(int groupindex, BindingSet bindings, SelectableSource targetModel) {
QueryStatement[] group = statements[groupindex];
QueryStatement qs = group[0];
int numMultiplyBound = IsMultiplyBound(qs.Subject, bindings)
+ IsMultiplyBound(qs.Predicate, bindings)
+ IsMultiplyBound(qs.Object, bindings);
if (numMultiplyBound >= 1) {
// If there is one or more multiply-bound variable,
// then we need to iterate through the permutations
// of the variables in the statement.
Debug(qs.ToString() + " Something Multiply Bound");
MemoryStore matches = new MemoryStore();
targetModel.Select(
new SelectFilter(
(Entity[])qs.Subject.GetValues(bindings.Union, true),
(Entity[])qs.Predicate.GetValues(bindings.Union, true),
qs.Object.GetValues(bindings.Union, false),
QueryMeta == null ? null : new Entity[] { QueryMeta }
),
new ClearMetaDupCheck(matches));
Debug("\t" + matches.StatementCount + " Matches");
if (matches.StatementCount == 0) {
// This statement doesn't match any of
// the existing bindings. If this was
// optional, preserve the bindings.
return qs.Optional;
}
// We need to preserve the pairings of
// the multiply bound variable with the matching
// statements.
ArrayList newbindings = new ArrayList();
if (!qs.Optional) bindings.Union.Clear(qs);
foreach (QueryResult binding in bindings.Results) {
// Break apart the permutations in this binding.
BindingEnumerator enumer2 = new BindingEnumerator(qs, binding);
Entity s, p;
Resource o;
while (enumer2.MoveNext(out s, out p, out o)) {
// Get the matching statements from the union query
Statement bs = new Statement(s, p, o);
MemoryStore innermatches = matches.Select(bs).Load();
// If no matches, the binding didn't match the filter.
if (innermatches.StatementCount == 0) {
if (qs.Optional) {
// Preserve the binding.
QueryResult bc = binding.Clone();
bc.Set(qs, bs);
newbindings.Add(bc);
continue;
} else {
// Toss out the binding.
continue;
}
}
for (int si = 0; si < innermatches.StatementCount; si++) {
Statement m = innermatches[si];
if (!MatchesFilters(m, qs, targetModel)) {
if (qs.Optional) {
QueryResult bc = binding.Clone();
bc.Set(qs, bs);
newbindings.Add(bc);
}
continue;
}
bindings.Union.Add(qs, m);
QueryResult r = binding.Clone();
r.Set(qs, m);
r.StatementMatched[groupindex] = true;
newbindings.Add(r);
}
}
}
bindings.Results = newbindings;
} else {
// There are no multiply bound variables, but if
// there are more than two unbound variables,
// we need to be sure to preserve the pairings
// of the matching values.
int numUnbound = IsUnbound(qs.Subject, bindings)
+ IsUnbound(qs.Predicate, bindings)
+ IsUnbound(qs.Object, bindings);
bool sunbound = IsUnbound(qs.Subject, bindings) == 1;
bool punbound = IsUnbound(qs.Predicate, bindings) == 1;
bool ounbound = IsUnbound(qs.Object, bindings) == 1;
Statement s = GetStatement(qs, bindings);
// If we couldn't get a statement out of this,
// then if this was not an optional filter,
// fail. If this was optional, don't change
// the bindings any.
if (s == StatementFailed) return qs.Optional;
if (numUnbound == 0) {
Debug(qs.ToString() + " All bound");
// All variables are singly bound already.
// We can just test if the statement exists.
if (targetModel.Contains(s)) {
// Mark each binding that it matched this statement.
foreach (QueryResult r in bindings.Results)
r.StatementMatched[groupindex] = true;
} else {
return qs.Optional;
}
} else if (numUnbound == 1) {
Debug(qs.ToString() + " 1 Unbound");
// There is just one unbound variable. The others
// are not multiply bound, so they must be uniquely
// bound (but they may not be bound in all results).
// Run a combined select to find all possible values
// of the unbound variable at once, and set these to
// be the values of the variable for matching results.
ResSet values = new ResSet();
MemoryStore ms = new MemoryStore();
targetModel.Select(s, ms);
for (int si = 0; si < ms.StatementCount; si++) {
Statement match = ms[si];
if (!MatchesFilters(match, qs, targetModel)) continue;
if (sunbound) values.Add(match.Subject);
if (punbound) values.Add(match.Predicate);
if (ounbound) values.Add(match.Object);
}
Debug("\t" + values.Count + " matches");
if (values.Count == 0)
return qs.Optional;
int varIndex = -1;
if (sunbound) varIndex = qs.Subject.VarIndex;
if (punbound) varIndex = qs.Predicate.VarIndex;
if (ounbound) varIndex = qs.Object.VarIndex;
if (bindings.Results.Count == 0)
bindings.Results.Add(new QueryResult(this));
bindings.Union.Bindings[varIndex] = new ResSet();
foreach (Resource r in values)
bindings.Union.Bindings[varIndex].Add(r);
foreach (QueryResult r in bindings.Results) {
// Check that the bound variables are bound in this result.
// If it is bound, it will be bound to the correct resource,
// but it might not be bound at all if an optional statement
// failed to match -- in which case, don't modify the binding.
if (qs.Subject.IsVariable && !sunbound && r.Bindings[qs.Subject.VarIndex] == null) continue;
if (qs.Predicate.IsVariable && !punbound && r.Bindings[qs.Predicate.VarIndex] == null) continue;
if (qs.Object.IsVariable && !ounbound && r.Bindings[qs.Object.VarIndex] == null) continue;
r.Bindings[varIndex] = values;
r.StatementMatched[groupindex] = true;
}
} else {
// There are two or more unbound variables, the
// third variable being uniquely bound, if bound.
// Keep track of the pairing of unbound variables.
if (numUnbound == 3)
throw new QueryExecutionException("Query would select all statements in the store.");
Debug(qs.ToString() + " 2 or 3 Unbound");
if (bindings.Results.Count == 0)
bindings.Results.Add(new QueryResult(this));
ArrayList newbindings = new ArrayList();
MemoryStore ms = new MemoryStore();
targetModel.Select(s, ms);
for (int si = 0; si < ms.StatementCount; si++) {
Statement match = ms[si];
if (!MatchesFilters(match, qs, targetModel)) continue;
bindings.Union.Add(qs, match);
foreach (QueryResult r in bindings.Results) {
if (numUnbound == 2) {
// Check that the bound variable is bound in this result.
// If it is bound, it will be bound to the correct resource,
// but it might not be bound at all if an optional statement
// failed to match -- in which case, preserve the binding if
// this was an optional statement.
bool matches = true;
if (qs.Subject.IsVariable && !sunbound && r.Bindings[qs.Subject.VarIndex] == null) matches = false;
if (qs.Predicate.IsVariable && !punbound && r.Bindings[qs.Predicate.VarIndex] == null) matches = false;
if (qs.Object.IsVariable && !ounbound && r.Bindings[qs.Object.VarIndex] == null) matches = false;
if (!matches) {
if (qs.Optional)
newbindings.Add(r);
continue;
}
}
QueryResult r2 = r.Clone();
r2.Add(qs, match);
r2.StatementMatched[groupindex] = true;
newbindings.Add(r2);
}
}
if (newbindings.Count == 0)
return qs.Optional; // don't clear out bindings if this was optional and it failed
bindings.Results = newbindings;
}
}
return true;
}
