PatternRules Class — spring-boot Architecture

Source Code

core/spring-boot/src/main/java/org/springframework/boot/logging/logback/SpringBootJoranConfigurator.java lines 365–430

	private static final class PatternRules {

		private static final String RESOURCE_LOCATION = "META-INF/spring/logback-pattern-rules";

		private final Context context;

		private PatternRules(Context context) {
			this.context = context;
		}

		private boolean load() {
			try {
				ClassPathResource resource = new ClassPathResource(RESOURCE_LOCATION);
				if (!resource.exists()) {
					return false;
				}
				Properties properties = PropertiesLoaderUtils.loadProperties(resource);
				Map<String, String> patternRuleRegistry = getRegistryMap();
				for (String word : properties.stringPropertyNames()) {
					patternRuleRegistry.put(word, properties.getProperty(word));
				}
				return true;
			}
			catch (Exception ex) {
				throw new RuntimeException(ex);
			}
		}

		@SuppressWarnings("unchecked")
		private Map<String, String> getRegistryMap() {
			Map<String, String> patternRuleRegistry = (Map<String, String>) this.context
				.getObject(CoreConstants.PATTERN_RULE_REGISTRY);
			if (patternRuleRegistry == null) {
				patternRuleRegistry = new HashMap<>();
				this.context.putObject(CoreConstants.PATTERN_RULE_REGISTRY, patternRuleRegistry);
			}
			return patternRuleRegistry;
		}

		private void save(GenerationContext generationContext) {
			Map<String, String> registryMap = getRegistryMap();
			byte[] rules = asBytes(registryMap);
			generationContext.getGeneratedFiles()
				.handleFile(Kind.RESOURCE, RESOURCE_LOCATION, new RequireNewOrMatchingContentFileHandler(rules));
			generationContext.getRuntimeHints().resources().registerPattern(RESOURCE_LOCATION);
			for (String ruleClassName : registryMap.values()) {
				generationContext.getRuntimeHints()
					.reflection()
					.registerType(TypeReference.of(ruleClassName), MemberCategory.INVOKE_PUBLIC_CONSTRUCTORS);
			}
		}

		private byte[] asBytes(Map<String, String> patternRuleRegistry) {
			Properties properties = CollectionFactory.createSortedProperties(true);
			patternRuleRegistry.forEach(properties::setProperty);
			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
			try {
				properties.store(bytes, "");
			}
			catch (IOException ex) {
				throw new RuntimeException(ex);
			}
			return bytes.toByteArray();
		}

	}