Exemplo n.º 1
0
  /**
   * Computes the number of results.
   *
   * @param qc query context (may be @code null)
   * @return number of results
   */
  private long size(final QueryContext qc) {
    final Value rt = initial(qc);
    // skip computation if value is not a document node
    if (rt == null || rt.type != NodeType.DOC) return -1;
    final Data data = rt.data();
    // skip computation if no database instance is available, is out-of-date or
    // if context does not contain all database nodes
    if (data == null || !data.meta.uptodate || data.resources.docs().size() != rt.size()) return -1;

    ArrayList<PathNode> nodes = data.paths.root();
    long m = 1;
    final int sl = steps.length;
    for (int s = 0; s < sl; s++) {
      final Step curr = axisStep(s);
      if (curr != null) {
        nodes = curr.nodes(nodes, data);
        if (nodes == null) return -1;
      } else if (s + 1 == sl) {
        m = steps[s].size();
      } else {
        // stop if a non-axis step is not placed last
        return -1;
      }
    }

    long sz = 0;
    for (final PathNode pn : nodes) sz += pn.stats.count;
    return sz * m;
  }
Exemplo n.º 2
0
 /**
  * Returns the root of the current context or {@code null}.
  *
  * @param ctx query context
  * @return root
  */
 final Value root(final QueryContext ctx) {
   final Value v = ctx != null ? ctx.value : null;
   // no root specified: return context, if it does not reference a document
   // as e.g. happens in //a(b|c)
   if (root == null) return v == null || v.type != NodeType.DOC ? v : null;
   // root is value: return root
   if (root.isValue()) return (Value) root;
   // no root reference, no context: return null
   if (!(root instanceof Root) || v == null) return null;
   // return context sequence or root of current context
   return v.size() == 1 ? Root.root(v) : v;
 }