private Vector decodeEvents()

in src/main/java/org/apache/log4j/xml/XMLDecoder.java [306:470]
132 lines of code
25 McCabe index (conditional complexity)

    private Vector<ChainsawLoggingEvent> decodeEvents(final Document document) {
        Vector<ChainsawLoggingEvent> events = new Vector<>();

        String logger;
        long timeStamp;
        String level;
        String threadName;
        String message = null;
        String ndc = null;
        String[] exception = null;
        String className = null;
        String methodName = null;
        String fileName = null;
        String lineNumber = null;
        Hashtable properties = null;

        NodeList nl = document.getElementsByTagName("log4j:eventSet");
        Node eventSet = nl.item(0);

        NodeList eventList = eventSet.getChildNodes();

        for (int eventIndex = 0; eventIndex < eventList.getLength();
             eventIndex++) {
            Node eventNode = eventList.item(eventIndex);
            //ignore carriage returns in xml
            if (eventNode.getNodeType() != Node.ELEMENT_NODE) {
                continue;
            }
            logger = eventNode.getAttributes().getNamedItem("logger").getNodeValue();
            timeStamp = Long.parseLong(eventNode.getAttributes().getNamedItem("timestamp").getNodeValue());
            level = eventNode.getAttributes().getNamedItem("level").getNodeValue();
            threadName = eventNode.getAttributes().getNamedItem("thread").getNodeValue();

            NodeList list = eventNode.getChildNodes();
            int listLength = list.getLength();

            if (listLength == 0) {
                continue;
            }

            for (int y = 0; y < listLength; y++) {
                String tagName = list.item(y).getNodeName();

                if (tagName.equalsIgnoreCase("log4j:message")) {
                    message = getCData(list.item(y));
                }

                if (tagName.equalsIgnoreCase("log4j:NDC")) {
                    ndc = getCData(list.item(y));
                }
                //still support receiving of MDC and convert to properties
                if (tagName.equalsIgnoreCase("log4j:MDC")) {
                    properties = new Hashtable();
                    NodeList propertyList = list.item(y).getChildNodes();
                    int propertyLength = propertyList.getLength();

                    for (int i = 0; i < propertyLength; i++) {
                        String propertyTag = propertyList.item(i).getNodeName();

                        if (propertyTag.equalsIgnoreCase("log4j:data")) {
                            Node property = propertyList.item(i);
                            String name =
                                property.getAttributes().getNamedItem("name").getNodeValue();
                            String value =
                                property.getAttributes().getNamedItem("value").getNodeValue();
                            properties.put(name, value);
                        }
                    }
                }

                if (tagName.equalsIgnoreCase("log4j:throwable")) {
                    String exceptionString = getCData(list.item(y));
                    if (exceptionString != null && !exceptionString.trim().equals("")) {
                        exception = new String[]{exceptionString.trim()
                        };
                    }
                }

                if (tagName.equalsIgnoreCase("log4j:locationinfo")) {
                    className =
                        list.item(y).getAttributes().getNamedItem("class").getNodeValue();
                    methodName =
                        list.item(y).getAttributes().getNamedItem("method").getNodeValue();
                    fileName =
                        list.item(y).getAttributes().getNamedItem("file").getNodeValue();
                    lineNumber =
                        list.item(y).getAttributes().getNamedItem("line").getNodeValue();
                }

                if (tagName.equalsIgnoreCase("log4j:properties")) {
                    if (properties == null) {
                        properties = new Hashtable();
                    }
                    NodeList propertyList = list.item(y).getChildNodes();
                    int propertyLength = propertyList.getLength();

                    for (int i = 0; i < propertyLength; i++) {
                        String propertyTag = propertyList.item(i).getNodeName();

                        if (propertyTag.equalsIgnoreCase("log4j:data")) {
                            Node property = propertyList.item(i);
                            String name =
                                property.getAttributes().getNamedItem("name").getNodeValue();
                            String value =
                                property.getAttributes().getNamedItem("value").getNodeValue();
                            properties.put(name, value);
                        }
                    }
                }

                /**
                 * We add all the additional properties to the properties
                 * hashtable. Override properties that already exist
                 */
                if (additionalProperties.size() > 0) {
                    if (properties == null) {
                        properties = new Hashtable(additionalProperties);
                    }
                    for (Object o : additionalProperties.entrySet()) {
                        Map.Entry e = (Map.Entry) o;
                        properties.put(e.getKey(), e.getValue());
                    }
                }
            }

            LocationInfo info;
            if ((fileName != null)
                || (className != null)
                || (methodName != null)
                || (lineNumber != null)) {
                info = new LocationInfo(fileName, className, methodName, 
                        Integer.parseInt(lineNumber));
            } else {
                info = null;
            }
//            ThrowableInformation throwableInfo = null;
//            if (exception != null) {
//                throwableInfo = new ThrowableInformation(exception);
//            }

            builder.clear();
            builder.setLogger(logger)
                    .setTimestamp(Instant.ofEpochMilli(timeStamp))
                    .setLevelFromString(level)
                    .setMessage(message)
                    .setThreadName(threadName)
                    .setMDC(properties)
                    .setNDC(ndc)
                    .setLocationInfo(info);


            events.add(builder.create());

            message = null;
            ndc = null;
            exception = null;
            className = null;
            methodName = null;
            fileName = null;
            lineNumber = null;
            properties = null;
        }

        return events;
    }