private Appender buildAppender()

in log4j-1.2-api/src/main/java/org/apache/log4j/xml/XmlConfiguration.java [378:441]
62 lines of code
15 McCabe index (conditional complexity)

    private Appender buildAppender(final String className, final Element appenderElement) {
        try {
            final Appender appender = LoaderUtil.newInstanceOf(className);
            final PropertySetter propSetter = new PropertySetter(appender);

            appender.setName(subst(appenderElement.getAttribute(NAME_ATTR)));
            final AtomicReference<Filter> filterChain = new AtomicReference<>();
            forEachElement(appenderElement.getChildNodes(), currentElement -> {
                // Parse appender parameters
                switch (currentElement.getTagName()) {
                    case PARAM_TAG:
                        setParameter(currentElement, propSetter);
                        break;
                    case LAYOUT_TAG:
                        appender.setLayout(parseLayout(currentElement));
                        break;
                    case FILTER_TAG:
                        addFilter(filterChain, currentElement);
                        break;
                    case ERROR_HANDLER_TAG:
                        parseErrorHandler(currentElement, appender);
                        break;
                    case APPENDER_REF_TAG:
                        final String refName = subst(currentElement.getAttribute(REF_ATTR));
                        if (appender instanceof AppenderAttachable) {
                            final AppenderAttachable aa = (AppenderAttachable) appender;
                            final Appender child = findAppenderByReference(currentElement);
                            LOGGER.debug("Attaching appender named [{}] to appender named [{}].", refName,
                                    appender.getName());
                            aa.addAppender(child);
                        } else {
                            LOGGER.error("Requesting attachment of appender named [{}] to appender named [{}]"
                                            + "which does not implement org.apache.log4j.spi.AppenderAttachable.",
                                    refName, appender.getName());
                        }
                        break;
                    default:
                        try {
                            parseUnrecognizedElement(appender, currentElement, props);
                        } catch (Exception ex) {
                            throw new ConsumerException(ex);
                        }
                }
            });
            final Filter head = filterChain.get();
            if (head != null) {
                appender.addFilter(head);
            }
            propSetter.activate();
            return appender;
        } catch (ConsumerException ex) {
            final Throwable t = ex.getCause();
            if (t instanceof InterruptedException || t instanceof InterruptedIOException) {
                Thread.currentThread().interrupt();
            }
            LOGGER.error("Could not create an Appender. Reported error follows.", t);
        } catch (Exception oops) {
            if (oops instanceof InterruptedException || oops instanceof InterruptedIOException) {
                Thread.currentThread().interrupt();
            }
            LOGGER.error("Could not create an Appender. Reported error follows.", oops);
        }
        return null;
    }