MessageSourceAutoConfiguration Class — spring-boot Architecture

Source Code

core/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/context/MessageSourceAutoConfiguration.java lines 67–162

@AutoConfiguration
@ConditionalOnMissingBean(name = AbstractApplicationContext.MESSAGE_SOURCE_BEAN_NAME, search = SearchStrategy.CURRENT)
@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE)
@Conditional(ResourceBundleCondition.class)
@EnableConfigurationProperties(MessageSourceProperties.class)
@ImportRuntimeHints(MessageSourceRuntimeHints.class)
public final class MessageSourceAutoConfiguration {

	private static final Resource[] NO_RESOURCES = {};

	@Bean
	MessageSource messageSource(MessageSourceProperties properties) {
		ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource();
		if (!CollectionUtils.isEmpty(properties.getBasename())) {
			messageSource.setBasenames(properties.getBasename().toArray(new String[0]));
		}
		if (properties.getEncoding() != null) {
			messageSource.setDefaultEncoding(properties.getEncoding().name());
		}
		messageSource.setFallbackToSystemLocale(properties.isFallbackToSystemLocale());
		Duration cacheDuration = properties.getCacheDuration();
		if (cacheDuration != null) {
			messageSource.setCacheMillis(cacheDuration.toMillis());
		}
		messageSource.setAlwaysUseMessageFormat(properties.isAlwaysUseMessageFormat());
		messageSource.setUseCodeAsDefaultMessage(properties.isUseCodeAsDefaultMessage());
		messageSource.setCommonMessages(loadCommonMessages(properties.getCommonMessages()));
		return messageSource;
	}

	private @Nullable Properties loadCommonMessages(@Nullable List<Resource> resources) {
		if (CollectionUtils.isEmpty(resources)) {
			return null;
		}
		Properties properties = CollectionFactory.createSortedProperties(false);
		for (Resource resource : resources) {
			try {
				PropertiesLoaderUtils.fillProperties(properties, resource);
			}
			catch (IOException ex) {
				throw new UncheckedIOException("Failed to load common messages from '%s'".formatted(resource), ex);
			}
		}
		return properties;
	}

	protected static class ResourceBundleCondition extends SpringBootCondition {

		private static final ConcurrentReferenceHashMap<String, ConditionOutcome> cache = new ConcurrentReferenceHashMap<>();

		@Override
		public ConditionOutcome getMatchOutcome(ConditionContext context, AnnotatedTypeMetadata metadata) {
			String basename = context.getEnvironment().getProperty("spring.messages.basename", "messages");
			ConditionOutcome outcome = cache.get(basename);
			if (outcome == null) {
				outcome = getMatchOutcomeForBasename(context, basename);
				cache.put(basename, outcome);
			}
			return outcome;
		}

		private ConditionOutcome getMatchOutcomeForBasename(ConditionContext context, String basename) {
			ConditionMessage.Builder message = ConditionMessage.forCondition("ResourceBundle");
			for (String name : StringUtils.commaDelimitedListToStringArray(StringUtils.trimAllWhitespace(basename))) {
				for (Resource resource : getResources(context.getClassLoader(), name)) {
					if (resource.exists()) {
						return ConditionOutcome.match(message.found("bundle").items(resource));
					}
				}
			}
			return ConditionOutcome.noMatch(message.didNotFind("bundle with basename " + basename).atAll());
		}

		private Resource[] getResources(@Nullable ClassLoader classLoader, String name) {
			String target = name.replace('.', '/');
			try {
				return new PathMatchingResourcePatternResolver(classLoader)
					.getResources("classpath*:" + target + ".properties");
			}
			catch (Exception ex) {
				return NO_RESOURCES;
			}
		}

	}

	static class MessageSourceRuntimeHints implements RuntimeHintsRegistrar {

		@Override
		public void registerHints(RuntimeHints hints, @Nullable ClassLoader classLoader) {
			hints.resources().registerPattern("messages.properties").registerPattern("messages_*.properties");
		}

	}

}