Class Genealogist

core/src/main/java/org/apache/calcite/sql/SqlUtil.java:1372–1447

Walks over a org.apache.calcite.sql.SqlNode tree and returns the ancestry stack when it finds a given node.

  /** Walks over a {@link org.apache.calcite.sql.SqlNode} tree and returns the
   * ancestry stack when it finds a given node. */
  private static class Genealogist extends SqlBasicVisitor<Void> {
    private final List<SqlNode> ancestors = new ArrayList<>();
    private final Predicate<SqlNode> predicate;
    private final Predicate<SqlNode> postPredicate;

    Genealogist(Predicate<SqlNode> predicate,
        Predicate<SqlNode> postPredicate) {
      this.predicate = predicate;
      this.postPredicate = postPredicate;
    }

    private Void check(SqlNode node) {
      preCheck(node);
      postCheck(node);
      return null;
    }

    private Void preCheck(SqlNode node) {
      if (predicate.test(node)) {
        throw new Util.FoundOne(ImmutableList.copyOf(ancestors));
      }
      return null;
    }

    private Void postCheck(SqlNode node) {
      if (postPredicate.test(node)) {
        throw new Util.FoundOne(ImmutableList.copyOf(ancestors));
      }
      return null;
    }

    private void visitChild(@Nullable SqlNode node) {
      if (node == null) {
        return;
      }
      ancestors.add(node);
      node.accept(this);
      ancestors.remove(ancestors.size() - 1);
    }

    @Override public Void visit(SqlIdentifier id) {
      return check(id);
    }

    @Override public Void visit(SqlCall call) {
      preCheck(call);
      for (SqlNode node : call.getOperandList()) {
        visitChild(node);
      }
      return postCheck(call);
    }

    @Override public Void visit(SqlIntervalQualifier intervalQualifier) {
      return check(intervalQualifier);
    }

    @Override public Void visit(SqlLiteral literal) {
      return check(literal);