protected void doConfigure()

in log4j-core/src/main/java/org/apache/logging/log4j/core/config/AbstractConfiguration.java [631:731]
95 lines of code
26 McCabe index (conditional complexity)

    protected void doConfigure() {
        processConditionals(rootNode);
        preConfigure(rootNode);
        configurationScheduler.start();
        if (rootNode.hasChildren() && rootNode.getChildren().get(0).getName().equalsIgnoreCase("Properties")) {
            final Node first = rootNode.getChildren().get(0);
            createConfiguration(first, null);
            if (first.getObject() != null) {
                final StrLookup lookup = (StrLookup) first.getObject();
                if (lookup instanceof LoggerContextAware) {
                    ((LoggerContextAware) lookup).setLoggerContext(loggerContext.get());
                }
                runtimeStrSubstitutor.setVariableResolver(lookup);
                configurationStrSubstitutor.setVariableResolver(lookup);
            }
        } else {
            final Map<String, String> map = this.getComponent(CONTEXT_PROPERTIES);
            final StrLookup lookup = map == null ? null : new PropertiesLookup(map);
            final Interpolator interpolator = new Interpolator(lookup, pluginPackages);
            interpolator.setLoggerContext(loggerContext.get());
            runtimeStrSubstitutor.setVariableResolver(interpolator);
            configurationStrSubstitutor.setVariableResolver(interpolator);
        }

        boolean setLoggers = false;
        boolean setRoot = false;
        for (final Node child : rootNode.getChildren()) {
            if (child.getName().equalsIgnoreCase("Properties")) {
                if (tempLookup == runtimeStrSubstitutor.getVariableResolver()) {
                    LOGGER.error("Properties declaration must be the first element in the configuration");
                }
                continue;
            }
            createConfiguration(child, null);
            if (child.getObject() == null) {
                continue;
            }
            if (child.getName().equalsIgnoreCase("Scripts")) {
                for (final AbstractScript script : child.getObject(AbstractScript[].class)) {
                    if (script instanceof ScriptRef) {
                        LOGGER.error("Script reference to {} not added. Scripts definition cannot contain script references",
                                script.getName());
                    } else if (scriptManager != null) {
                        scriptManager.addScript(script);
                    }
                }
            } else if (child.getName().equalsIgnoreCase("Appenders")) {
                appenders = child.getObject();
            } else if (child.isInstanceOf(Filter.class)) {
                addFilter(child.getObject(Filter.class));
            } else if (child.getName().equalsIgnoreCase("Loggers")) {
                final Loggers l = child.getObject();
                loggerConfigs = l.getMap();
                setLoggers = true;
                if (l.getRoot() != null) {
                    root = l.getRoot();
                    setRoot = true;
                }
            } else if (child.getName().equalsIgnoreCase("CustomLevels")) {
                customLevels = child.getObject(CustomLevels.class).getCustomLevels();
            } else if (child.isInstanceOf(CustomLevelConfig.class)) {
                final List<CustomLevelConfig> copy = new ArrayList<>(customLevels);
                copy.add(child.getObject(CustomLevelConfig.class));
                customLevels = copy;
            } else if (child.isInstanceOf(AsyncWaitStrategyFactoryConfig.class)) {
                final AsyncWaitStrategyFactoryConfig awsfc = child.getObject(AsyncWaitStrategyFactoryConfig.class);
                asyncWaitStrategyFactory = awsfc.createWaitStrategyFactory();
            } else {
                final List<String> expected = Arrays.asList("\"Appenders\"", "\"Loggers\"", "\"Properties\"",
                        "\"Scripts\"", "\"CustomLevels\"");
                LOGGER.error("Unknown object \"{}\" of type {} is ignored: try nesting it inside one of: {}.",
                        child.getName(), child.getObject().getClass().getName(), expected);
            }
        }

        if (!setLoggers) {
            LOGGER.warn("No Loggers were configured, using default. Is the Loggers element missing?");
            setToDefault();
            return;
        } else if (!setRoot) {
            LOGGER.warn("No Root logger was configured, creating default ERROR-level Root logger with Console appender");
            setToDefault();
            // return; // LOG4J2-219: creating default root=ok, but don't exclude configured Loggers
        }

        for (final Map.Entry<String, LoggerConfig> entry : loggerConfigs.entrySet()) {
            final LoggerConfig loggerConfig = entry.getValue();
            for (final AppenderRef ref : loggerConfig.getAppenderRefs()) {
                final Appender app = appenders.get(ref.getRef());
                if (app != null) {
                    loggerConfig.addAppender(app, ref.getLevel(), ref.getFilter());
                } else {
                    LOGGER.error("Unable to locate appender \"{}\" for logger config \"{}\"", ref.getRef(),
                            loggerConfig);
                }
            }

        }

        setParents();
    }