/**
   * Returns atomic text node merging operations if necessary for the given node PRE and its right
   * neighbor PRE+1.
   *
   * @param a node PRE value
   * @param d target data reference
   * @return list of text merging operations
   */
  private AtomicUpdateList necessaryMerges(final int a, final Data d) {
    final AtomicUpdateList mergeTwoNodes = new AtomicUpdateList(d);
    final int s = d.meta.size;
    final int b = a + 1;
    // don't leave table
    if (a >= s || b >= s || a < 0 || b < 0) return mergeTwoNodes;
    // only merge texts
    if (d.kind(a) != Data.TEXT || d.kind(b) != Data.TEXT) return mergeTwoNodes;
    // only merge neighboring texts
    if (d.parent(a, Data.TEXT) != d.parent(b, Data.TEXT)) return mergeTwoNodes;

    mergeTwoNodes.addDelete(b);
    mergeTwoNodes.addUpdateValue(a, Data.TEXT, Token.concat(d.text(a, true), d.text(b, true)));

    return mergeTwoNodes;
  }
  /**
   * Resolves unwanted text node adjacency which can result from structural changes in the database.
   * Adjacent text nodes are two text nodes A and B, where PRE(B)=PRE(A)+1 and PARENT(A)=PARENT(B).
   */
  private void resolveTextAdjacency() {
    // Text node merges are also gathered on a separate list to leverage optimizations.
    final AtomicUpdateList allMerges = new AtomicUpdateList(data);

    // keep track of the visited locations to avoid superfluous checks
    final IntSet s = new IntSet();
    // Text nodes have to be merged from the highest to the lowest pre value
    for (int i = 0; i < updStructural.size(); i++) {
      final BasicUpdate u = updStructural.get(i);
      final Data insseq = u.getInsertionData();
      // calculate the new location of the update, here we have to check for adjacency
      final int newLocation = u.location + u.accumulatedShifts - u.shifts;
      final int beforeNewLocation = newLocation - 1;
      // check surroundings of this location for adjacent text nodes depending on the
      // kind of update, first the one with higher PRE values (due to shifts!)
      // ... for insert/replace ...
      if (insseq != null) {
        // calculate the current following node
        final int followingNode = newLocation + insseq.meta.size;
        final int beforeFollowingNode = followingNode - 1;
        // check the nodes at the end of/after the insertion sequence
        if (!s.contains(beforeFollowingNode)) {
          final AtomicUpdateList merges = necessaryMerges(beforeFollowingNode, allMerges.data);
          mergeNodes(merges);
          allMerges.merge(merges);
          s.add(beforeFollowingNode);
        }
      }
      // check nodes for delete and for insert before the updated location
      if (!s.contains(beforeNewLocation)) {
        final AtomicUpdateList merges = necessaryMerges(beforeNewLocation, allMerges.data);
        mergeNodes(merges);
        allMerges.merge(merges);
        s.add(beforeNewLocation);
      }
    }

    allMerges.updateDistances();
    allMerges.clear();
  }
Exemple #3
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 @Override
 public void addAtomics(final AtomicUpdateList l) {
   l.addReplace(targetPre, insseq);
 }
 /**
  * Applies text node merges of the given list.
  *
  * @param mergeTexts list of atomic text node merging operations
  */
 private void mergeNodes(final AtomicUpdateList mergeTexts) {
   mergeTexts.check();
   mergeTexts.applyValueUpdates();
   mergeTexts.applyStructuralUpdates();
 }