ComponentScanPackageCheck Class — spring-boot Architecture

Source Code

core/spring-boot/src/main/java/org/springframework/boot/context/ConfigurationWarningsApplicationContextInitializer.java lines 129–214

	protected static class ComponentScanPackageCheck implements Check {

		private static final Set<String> PROBLEM_PACKAGES;

		static {
			Set<String> packages = new HashSet<>();
			packages.add("org.springframework");
			packages.add("org");
			PROBLEM_PACKAGES = Collections.unmodifiableSet(packages);
		}

		@Override
		public @Nullable String getWarning(BeanDefinitionRegistry registry) {
			Set<String> scannedPackages = getComponentScanningPackages(registry);
			List<String> problematicPackages = getProblematicPackages(scannedPackages);
			if (problematicPackages.isEmpty()) {
				return null;
			}
			return "Your ApplicationContext is unlikely to start due to a @ComponentScan of "
					+ StringUtils.collectionToDelimitedString(problematicPackages, ", ") + ".";
		}

		protected Set<String> getComponentScanningPackages(BeanDefinitionRegistry registry) {
			Set<String> packages = new LinkedHashSet<>();
			String[] names = registry.getBeanDefinitionNames();
			for (String name : names) {
				BeanDefinition definition = registry.getBeanDefinition(name);
				if (definition instanceof AnnotatedBeanDefinition annotatedDefinition) {
					addComponentScanningPackages(packages, annotatedDefinition.getMetadata());
				}
			}
			return packages;
		}

		private void addComponentScanningPackages(Set<String> packages, AnnotationMetadata metadata) {
			AnnotationAttributes attributes = AnnotationAttributes
				.fromMap(metadata.getAnnotationAttributes(ComponentScan.class.getName(), true));
			if (attributes != null) {
				addPackages(packages, attributes.getStringArray("value"));
				addPackages(packages, attributes.getStringArray("basePackages"));
				addClasses(packages, attributes.getStringArray("basePackageClasses"));
				if (packages.isEmpty()) {
					packages.add(ClassUtils.getPackageName(metadata.getClassName()));
				}
			}
		}

		private void addPackages(Set<String> packages, String @Nullable [] values) {
			if (values != null) {
				Collections.addAll(packages, values);
			}
		}

		private void addClasses(Set<String> packages, String @Nullable [] values) {
			if (values != null) {
				for (String value : values) {
					packages.add(ClassUtils.getPackageName(value));
				}
			}
		}

		private List<String> getProblematicPackages(Set<String> scannedPackages) {
			List<String> problematicPackages = new ArrayList<>();
			for (String scannedPackage : scannedPackages) {
				if (isProblematicPackage(scannedPackage)) {
					problematicPackages.add(getDisplayName(scannedPackage));
				}
			}
			return problematicPackages;
		}

		private boolean isProblematicPackage(@Nullable String scannedPackage) {
			if (scannedPackage == null || scannedPackage.isEmpty()) {
				return true;
			}
			return PROBLEM_PACKAGES.contains(scannedPackage);
		}

		private String getDisplayName(@Nullable String scannedPackage) {
			if (scannedPackage == null || scannedPackage.isEmpty()) {
				return "the default package";
			}
			return "'" + scannedPackage + "'";
		}

	}