public static Op applyCovers(
Op parentOp, SparqlViewCache conceptMap, Map<Op, CacheResult> opToCover) {
Op result;
CacheResult cacheResult = opToCover.get(parentOp);
if (cacheResult == null) {
// Recursively descend to the children
List<Op> subOps = OpUtils.getSubOps(parentOp);
List<Op> newSubOps =
subOps
.stream()
.map(child -> applyCovers(child, conceptMap, opToCover))
.collect(Collectors.toList());
result = OpUtils.copy(parentOp, newSubOps);
} else {
// CacheHit cacheHit = cacheHits.iterator().next();
// CacheResult cacheResult = cacheHits;
QuadFilterPatternCanonical qfpc = cacheResult.getReplacementPattern();
Op o = qfpc.toOp();
Collection<Table> tables = cacheResult.getTables();
Op opTable = null;
for (Table table : tables) {
Op tmp = OpTable.create(table);
if (opTable == null) {
opTable = tmp;
} else {
opTable = OpJoin.create(opTable, tmp);
}
}
// System.out.println("Table size: " + table.size());
if (o instanceof OpNull) {
result = opTable;
} else {
result = OpJoin.create(opTable, o);
}
}
return result;
}
