private static Document toDocument()

in nouveau/src/main/java/org/apache/couchdb/nouveau/lucene9/Lucene9Index.java [405:459]
47 lines of code
15 McCabe index (conditional complexity)

    private static Document toDocument(final String docId, final DocumentUpdateRequest request) throws IOException {
        final Document result = new Document();

        // id
        result.add(new org.apache.lucene.document.StringField("_id", docId, Store.YES));
        result.add(new SortedDocValuesField("_id", new BytesRef(docId)));

        // partition (optional)
        if (request.hasPartition()) {
            result.add(new org.apache.lucene.document.StringField("_partition", request.getPartition(), Store.NO));
        }

        final CharsetDecoder utf8Decoder = Charset.forName("UTF-8").newDecoder();

        for (Field field : request.getFields()) {
            // Underscore-prefix is reserved.
            if (field.getName().startsWith("_")) {
                continue;
            }
            if (field instanceof TextField) {
                var f = (TextField) field;
                result.add(new org.apache.lucene.document.TextField(
                        f.getName(), f.getValue(), f.isStore() ? Store.YES : Store.NO));
            } else if (field instanceof StringField) {
                var f = (StringField) field;
                result.add(new org.apache.lucene.document.KeywordField(
                        f.getName(), f.getValue(), f.isStore() ? Store.YES : Store.NO));
            } else if (field instanceof DoubleField) {
                var f = (DoubleField) field;
                result.add(new org.apache.lucene.document.DoubleField(
                        f.getName(), f.getValue(), f.isStore() ? Store.YES : Store.NO));
            } else if (field instanceof StoredField) {
                var f = (StoredField) field;
                var val = f.getValue();
                if (val instanceof String) {
                    result.add(new org.apache.lucene.document.StoredField(f.getName(), (String) val));
                } else if (val instanceof Number) {
                    result.add(new org.apache.lucene.document.StoredField(f.getName(), ((Number) val).doubleValue()));
                } else if (val instanceof byte[]) {
                    try {
                        final CharBuffer buf = utf8Decoder.decode(ByteBuffer.wrap((byte[]) val));
                        result.add(new org.apache.lucene.document.StoredField(f.getName(), buf.toString()));
                    } catch (final CharacterCodingException e) {
                        result.add(new org.apache.lucene.document.StoredField(f.getName(), (byte[]) val));
                    }
                } else {
                    throw new WebApplicationException(field + " is not valid", Status.BAD_REQUEST);
                }
            } else {
                throw new WebApplicationException(field + " is not valid", Status.BAD_REQUEST);
            }
        }

        return result;
    }