JavaLoggingSystem Class — spring-boot Architecture

Source Code

core/spring-boot/src/main/java/org/springframework/boot/logging/java/JavaLoggingSystem.java lines 58–198

public class JavaLoggingSystem extends AbstractLoggingSystem {

	private static final LogLevels<Level> LEVELS = new LogLevels<>();

	static {
		LEVELS.map(LogLevel.TRACE, Level.FINEST);
		LEVELS.map(LogLevel.DEBUG, Level.FINE);
		LEVELS.map(LogLevel.INFO, Level.INFO);
		LEVELS.map(LogLevel.WARN, Level.WARNING);
		LEVELS.map(LogLevel.ERROR, Level.SEVERE);
		LEVELS.map(LogLevel.FATAL, Level.SEVERE);
		LEVELS.map(LogLevel.OFF, Level.OFF);
	}

	private final Set<Logger> configuredLoggers = Collections.synchronizedSet(new HashSet<>());

	public JavaLoggingSystem(ClassLoader classLoader) {
		super(classLoader);
	}

	@Override
	protected String[] getStandardConfigLocations() {
		return new String[] { "logging.properties" };
	}

	@Override
	public void beforeInitialize() {
		super.beforeInitialize();
		Logger.getLogger("").setLevel(Level.SEVERE);
	}

	@Override
	protected void loadDefaults(LoggingInitializationContext initializationContext, @Nullable LogFile logFile) {
		if (logFile != null) {
			loadConfiguration(getPackagedConfigFile("logging-file.properties"), logFile);
		}
		else {
			loadConfiguration(getPackagedConfigFile("logging.properties"), null);
		}
	}

	@Override
	protected void loadConfiguration(LoggingInitializationContext initializationContext, String location,
			@Nullable LogFile logFile) {
		loadConfiguration(location, logFile);
	}

	protected void loadConfiguration(String location, @Nullable LogFile logFile) {
		Assert.notNull(location, "'location' must not be null");
		try {
			Resource resource = ApplicationResourceLoader.get().getResource(location);
			String configuration = FileCopyUtils.copyToString(new InputStreamReader(resource.getInputStream()));
			if (logFile != null) {
				configuration = configuration.replace("${LOG_FILE}", StringUtils.cleanPath(logFile.toString()));
			}
			LogManager.getLogManager().readConfiguration(new ByteArrayInputStream(configuration.getBytes()));
		}
		catch (Exception ex) {
			throw new IllegalStateException("Could not initialize Java logging from " + location, ex);
		}
	}

	@Override
	public Set<LogLevel> getSupportedLogLevels() {
		return LEVELS.getSupported();
	}

	@Override
	public void setLogLevel(@Nullable String loggerName, @Nullable LogLevel level) {
		if (loggerName == null || ROOT_LOGGER_NAME.equals(loggerName)) {
			loggerName = "";
		}
		Logger logger = Logger.getLogger(loggerName);
		if (logger != null) {
			this.configuredLoggers.add(logger);
			logger.setLevel(LEVELS.convertSystemToNative(level));
		}
	}

	@Override
	public List<LoggerConfiguration> getLoggerConfigurations() {
		List<LoggerConfiguration> result = new ArrayList<>();
		Enumeration<String> names = LogManager.getLogManager().getLoggerNames();
		while (names.hasMoreElements()) {
			result.add(getLoggerConfiguration(names.nextElement()));
		}
		result.sort(CONFIGURATION_COMPARATOR);
		return Collections.unmodifiableList(result);
	}

	@Override
	public @Nullable LoggerConfiguration getLoggerConfiguration(String loggerName) {
		Logger logger = Logger.getLogger(loggerName);
		if (logger == null) {
			return null;
		}
		LogLevel level = LEVELS.convertNativeToSystem(logger.getLevel());
		LogLevel effectiveLevel = LEVELS.convertNativeToSystem(getEffectiveLevel(logger));
		String name = (StringUtils.hasLength(logger.getName()) ? logger.getName() : ROOT_LOGGER_NAME);
		Assert.state(effectiveLevel != null, "effectiveLevel must not be null");
		return new LoggerConfiguration(name, level, effectiveLevel);
	}

	private Level getEffectiveLevel(Logger root) {
		Logger logger = root;
		while (logger.getLevel() == null) {
			logger = logger.getParent();
		}
		return logger.getLevel();
	}

	@Override
	public Runnable getShutdownHandler() {
		return () -> LogManager.getLogManager().reset();
	}

	@Override
	public void cleanUp() {
		this.configuredLoggers.clear();
	}

	/**
	 * {@link LoggingSystemFactory} that returns {@link JavaLoggingSystem} if possible.
	 */
	@Order(Ordered.LOWEST_PRECEDENCE - 1024)
	public static class Factory implements LoggingSystemFactory {

		private static final boolean PRESENT = ClassUtils.isPresent("java.util.logging.LogManager",
				Factory.class.getClassLoader());

		@Override
		public @Nullable LoggingSystem getLoggingSystem(ClassLoader classLoader) {
			if (PRESENT) {
				return new JavaLoggingSystem(classLoader);
			}
			return null;
		}

	}

}