Examples with EmptyNodeSet org.exist.dom.persistent.EmptyNodeSet used on opensource projects

Example 1 with EmptyNodeSet

use of org.exist.dom.persistent.EmptyNodeSet in project exist by eXist-db.

the class NGramSearch method fixedStringSearch.

public NodeSet fixedStringSearch(final NGramIndexWorker index, final DocumentSet docs, final List<QName> qnames, final String query, final NodeSet nodeSet, final int axis) throws XPathException {
    String[] ngrams = NGramSearch.getDistinctNGrams(query, index.getN());
    // Nothing to search for? The find nothing.
    if (ngrams.length == 0)
        return new EmptyNodeSet();
    String firstNgramm = ngrams[0];
    LOG.trace("First NGRAM: {}", firstNgramm);
    NodeSet result = index.search(getExpressionId(), docs, qnames, firstNgramm, firstNgramm, context, nodeSet, axis);
    for (int i = 1; i < ngrams.length; i++) {
        String ngram = ngrams[i];
        int len = ngram.codePointCount(0, ngram.length());
        int fillSize = index.getN() - len;
        String filledNgram = ngram;
        // ngrams lead to a considerable performance loss.
        if (fillSize > 0) {
            String filler = ngrams[i - 1];
            StringBuilder buf = new StringBuilder();
            int pos = filler.offsetByCodePoints(0, len);
            for (int j = 0; j < fillSize; j++) {
                int codepoint = filler.codePointAt(pos);
                pos += Character.charCount(codepoint);
                buf.appendCodePoint(codepoint);
            }
            buf.append(ngram);
            filledNgram = buf.toString();
            LOG.debug("Filled: {}", filledNgram);
        }
        NodeSet nodes = index.search(getExpressionId(), docs, qnames, filledNgram, ngram, context, nodeSet, axis);
        final NodeSet nodesContainingFirstINgrams = result;
        result = NodeSets.transformNodes(nodes, proxy -> Optional.ofNullable(nodesContainingFirstINgrams.get(proxy)).map(before -> getContinuousMatches(before, proxy)).orElse(null));
    }
    return result;
}

Example 2 with EmptyNodeSet

use of org.exist.dom.persistent.EmptyNodeSet in project exist by eXist-db.

the class WildcardedExpressionSequence method eval.

@Override
public NodeSet eval(final NGramIndexWorker index, final DocumentSet docs, final List<QName> qnames, final NodeSet nodeSet, final int axis, final int expressionId) throws XPathException {
    boolean startAnchorPresent = false;
    if (!expressions.isEmpty() && expressions.get(0) instanceof StartAnchor) {
        startAnchorPresent = true;
        expressions.remove(0);
    }
    Wildcard leadingWildcard = null;
    if (!expressions.isEmpty() && expressions.get(0) instanceof Wildcard)
        leadingWildcard = (Wildcard) expressions.remove(0);
    boolean endAnchorPresent = false;
    if (!expressions.isEmpty() && expressions.get(expressions.size() - 1) instanceof EndAnchor) {
        endAnchorPresent = true;
        expressions.remove(expressions.size() - 1);
    }
    Wildcard trailingWildcard = null;
    if (!expressions.isEmpty() && expressions.get(expressions.size() - 1) instanceof Wildcard)
        trailingWildcard = (Wildcard) expressions.remove(expressions.size() - 1);
    while (expressions.size() >= 3) {
        formEvaluatableTriples(expressionId);
    }
    if (expressions.isEmpty())
        return new EmptyNodeSet();
    if (expressions.size() != 1 || !(expressions.get(0) instanceof EvaluatableExpression)) {
        // Should not happen.
        LOG.error("Expression {} could not be evaluated", toString());
        throw new XPathException("Could not evaluate wildcarded query.");
    }
    LOG.trace("Evaluating expression {}", toString());
    NodeSet result = ((EvaluatableExpression) expressions.get(0)).eval(index, docs, qnames, nodeSet, axis, expressionId);
    if (leadingWildcard != null)
        result = expandMatchesBackward(leadingWildcard, result, expressionId);
    if (startAnchorPresent)
        result = NodeSets.getNodesMatchingAtStart(result, expressionId);
    if (trailingWildcard != null)
        result = expandMatchesForward(trailingWildcard, result, expressionId);
    if (endAnchorPresent)
        result = NodeSets.getNodesMatchingAtEnd(result, expressionId);
    return result;
}