Method check

basex-core/src/main/java/org/basex/core/parse/XMLParser.java:254–314

Checks the syntax of the specified command. Returns an error with the expected syntax if the check fails. The passed on strings describe the arguments of a command. They may be: attribute names labels for text nodes if prefixed with "#" labels for text or descenda

(final XNode root, final String... checks)

   * @throws QueryException query exception
   */
  private boolean check(final XNode root, final String... checks) throws QueryException {
    // prepare validating query
    final TokenList mand = new TokenList(), opt = new TokenList();
    String t = null;
    boolean ot = true;
    boolean n = false;
    for(String check : checks) {
      final boolean o = Strings.endsWith(check, '?');
      check = check.replace("?", "");
      if(!check.isEmpty() && !Character.isLetter(check.charAt(0))) {
        // textual contents
        t = check.substring(1);
        ot = o;
        n = check.charAt(0) == '<';
      } else {
        (o ? opt : mand).add(check);
      }
    }

    // build validating query
    final TokenBuilder tb = new TokenBuilder();
    tb.add("declare variable $A external;");
    tb.add("declare variable $O external;");
    tb.add(".");
    // check existence of mandatory attributes
    tb.add("[every $e in $A satisfies @*/name() = $e]");
    // check existence of unknown attributes
    tb.add("[every $e in @* satisfies $e/name() = ($A, $O)]");
    // ensure that all values are non-empty
    tb.add("[every $e in @* satisfies data($e)]");
    if(t == null) {
      // ensure that no children exist
      tb.add("[not(node())]");
    } else if(!ot) {
      // ensure that children exist
      tb.add("[node()]");
      if(!n) tb.add("[not(*)]");
    }

    // run query
    try(QueryProcessor qp = new QueryProcessor(tb.toString(), ctx).context(root)) {
      qp.variable("A", StrSeq.get(mand.toArray())).variable("O", StrSeq.get(opt.toArray()));
      if(!qp.value().isEmpty()) return true;
    }
    // build error string
    final TokenBuilder syntax = new TokenBuilder();
    final byte[] nm = root.qname().string();
    syntax.reset().add('<').add(nm);
    for(final byte[] m : mand) syntax.add(' ').add(m).add("=\"...\"");
    for(final byte[] o : opt) syntax.add(" (").add(o).add("=\"...\")");
    if(t != null) {
      syntax.add('>');
      if(ot) syntax.add('(');
      syntax.add('[').add(t).add(']');
      if(ot) syntax.add(')');
      syntax.add("</").add(nm).add('>');
    } else {
      syntax.add("/>");