private BsonDocument extractBsonDocument(Struct value, Schema valueSchema, String fieldName) {
        if (valueSchema.field(fieldName) != null) {
            String docString = value.getString(fieldName);
            if (docString != null) {
                return BsonDocument.parse(docString);
            }
        }
        return null;
    }
Validator to validate the row value.
inlong-sort/sort-flink/sort-flink-v1.13/sort-connectors/mongodb-cdc/src/main/java/org/apache/inlong/sort/cdc/mongodb/debezium/table/MongoDBConnectorDeserializationSchema.java