Exemple #1
0
  @Override
  public Value value(final QueryContext qc) throws QueryException {
    final FItem getKey = checkArity(exprs[1], 1, qc);
    final long k = Math.min(toLong(exprs[2], qc), Integer.MAX_VALUE);
    if (k < 1) return Empty.SEQ;

    final Iter iter = exprs[0].iter(qc);
    final MinHeap<Item, Item> heap =
        new MinHeap<>(
            new Comparator<Item>() {
              @Override
              public int compare(final Item it1, final Item it2) {
                try {
                  return OpV.LT.eval(it1, it2, sc.collation, sc, info) ? -1 : 1;
                } catch (final QueryException qe) {
                  throw new QueryRTException(qe);
                }
              }
            });

    try {
      for (Item it; (it = iter.next()) != null; ) {
        heap.insert(checkNoEmpty(getKey.invokeItem(qc, info, it)), it);
        if (heap.size() > k) heap.removeMin();
      }
    } catch (final QueryRTException ex) {
      throw ex.getCause();
    }

    final ValueBuilder vb = new ValueBuilder();
    while (!heap.isEmpty()) vb.addFront(heap.removeMin());
    return vb.value();
  }
Exemple #2
0
  @Override
  public Value value(final QueryContext qc) throws QueryException {
    final FItem f = checkArity(exprs[1], 1, qc);
    final Iter iter = exprs[0].iter(qc);
    Item it = iter.next();
    if (it == null) return Empty.SEQ;
    final Value v1 = f.invokeValue(qc, info, it);
    it = iter.next();
    if (it == null) return v1;

    final ValueBuilder vb = new ValueBuilder().add(v1);
    do {
      vb.add(f.invokeValue(qc, info, it));
    } while ((it = iter.next()) != null);
    return vb.value();
  }