Examples with AlternativeStrings org.exist.xquery.modules.ngram.query.AlternativeStrings used on opensource projects

Example 1 with AlternativeStrings

use of org.exist.xquery.modules.ngram.query.AlternativeStrings in project exist by eXist-db.

the class NGramSearch method parseQuery.

private EvaluatableExpression parseQuery(final String query) throws XPathException {
    List<String> queryTokens = tokenizeQuery(query);
    LOG.trace("Tokenized query: {}", queryTokens);
    if (queryTokens.isEmpty())
        return new EmptyExpression();
    List<WildcardedExpression> expressions = new ArrayList<>();
    if (queryTokens.get(0).equals("^")) {
        expressions.add(new StartAnchor());
        queryTokens.remove(0);
    }
    if (queryTokens.isEmpty())
        return new EmptyExpression();
    boolean endAnchorPresent = false;
    if (queryTokens.get(queryTokens.size() - 1).equals("$")) {
        endAnchorPresent = true;
        queryTokens.remove(queryTokens.size() - 1);
    }
    if (queryTokens.isEmpty())
        return new EmptyExpression();
    for (String token : queryTokens) {
        if (token.startsWith(".")) {
            Wildcard wildcard = null;
            if (token.length() == 1) {
                wildcard = new Wildcard(1, 1);
            } else {
                String qualifier = token.substring(1);
                switch(qualifier) {
                    case "?":
                        wildcard = new Wildcard(0, 1);
                        break;
                    case "*":
                        wildcard = new Wildcard(0, Integer.MAX_VALUE);
                        break;
                    case "+":
                        wildcard = new Wildcard(1, Integer.MAX_VALUE);
                        break;
                    default:
                        Pattern p = Pattern.compile(INTERVAL_QUALIFIER_PATTERN);
                        Matcher m = p.matcher(qualifier);
                        if (// Should not happen
                        !m.matches())
                            throw new XPathException(this, ErrorCodes.FTDY0020, "query string violates wildcard qualifier syntax");
                        try {
                            wildcard = new Wildcard(Integer.parseInt(m.group(1)), Integer.parseInt(m.group(2)));
                        } catch (NumberFormatException nfe) {
                            throw new XPathException(this, ErrorCodes.FTDY0020, "query string violates wildcard qualifier syntax", new StringValue(query), nfe);
                        }
                        break;
                }
            }
            expressions.add(wildcard);
        } else {
            if (token.startsWith("[")) {
                Set<String> strings = new HashSet<>(token.length() - 2);
                for (int i = 1; i < token.length() - 1; i++) strings.add(Character.toString(token.charAt(i)));
                expressions.add(new AlternativeStrings(this, strings));
            } else {
                expressions.add(new FixedString(this, unescape(token)));
            }
        }
    }
    if (endAnchorPresent)
        expressions.add(new EndAnchor());
    return new WildcardedExpressionSequence(expressions);
}