private static Op transformFilterQuadPattern(
ExprList exprs, Set<Var> patternVarsScope, Node graphNode, BasicPattern pattern) {
// Any filters that depend on no variables.
Op op = insertAnyFilter(exprs, patternVarsScope, null);
if (Var.isVar(graphNode)) {
// Add in the graph node of the quad block.
// It's picked up after the first triple is processed.
VarUtils.addVar(patternVarsScope, Var.alloc(graphNode));
}
for (Triple triple : pattern) {
OpQuadPattern opQuad = getQuads(op);
if (opQuad == null) {
opQuad = new OpQuadPattern(graphNode, new BasicPattern());
op = OpSequence.create(op, opQuad);
}
opQuad.getBasicPattern().add(triple);
// Update variables in scope.
VarUtils.addVarsFromTriple(patternVarsScope, triple);
// Attempt to place any filters
op = insertAnyFilter(exprs, patternVarsScope, op);
}
return op;
}
private static Op transformFilterBGP(
ExprList exprs, Set<Var> patternVarsScope, BasicPattern pattern) {
// Any filters that depend on no variables.
Op op = insertAnyFilter(exprs, patternVarsScope, null);
for (Triple triple : pattern) {
OpBGP opBGP = getBGP(op);
if (opBGP == null) {
// Last thing was not a BGP (so it likely to be a filter)
// Need to pass the results from that into the next triple.
// Which is a join and sequence is a special case of join
// which always evaluates by passing results of the early
// part into the next element of the sequence.
opBGP = new OpBGP();
op = OpSequence.create(op, opBGP);
}
opBGP.getPattern().add(triple);
// Update variables in scope.
VarUtils.addVarsFromTriple(patternVarsScope, triple);
// Attempt to place any filters
op = insertAnyFilter(exprs, patternVarsScope, op);
}
// Leave any remaining filter expressions - don't wrap up any as something else may take them.
return op;
}
public static void addVars(Collection<Var> acc, Collection<Triple> triples) {
for (Triple triple : triples) addVarsFromTriple(acc, triple);
}
public static Set<Var> getVars(Triple triple) {
Set<Var> x = new HashSet<Var>();
addVarsFromTriple(x, triple);
return x;
}