}
            accessResultData.setId(accessResult.getId());

            final Map<String, AccessResultImpl<Long>> arMap = dataHelper.getAccessResultMap(accessResult.getSessionId());
            if (arMap.containsKey(accessResult.getUrl())) {
                throw new CrawlerSystemException(accessResult.getUrl() + " already exists.");
            }
            arMap.put(accessResult.getUrl(), accessResult);
        }

    }

                    fieldName = null;
                }
                buffer.setLength(0);
            } else if ("list".equals(qName)) {
                if (fieldName != null && !dataMap.containsKey(fieldName)) {
                    dataMap.put(fieldName, new ArrayList<>());
                }
            } else if ("item".equals(qName)) {
                buffer.setLength(0);
            }
        }

            throw new CrawlerSystemException("The key is null.");
        }
        if (extractor == null) {
            throw new CrawlerSystemException("The extractor is null.");
        }
        if (extractorMap.containsKey(key)) {
            final Extractor[] existingExtractors = extractorMap.get(key);

            final Extractor[] newExtractors = new Extractor[existingExtractors.length + 1];