AutoConfigurationPackages Class — spring-boot Architecture

Source Code

core/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/AutoConfigurationPackages.java lines 53–230

public abstract class AutoConfigurationPackages {

	private static final Log logger = LogFactory.getLog(AutoConfigurationPackages.class);

	private static final String BEAN = AutoConfigurationPackages.class.getName();

	/**
	 * Determine if the auto-configuration base packages for the given bean factory are
	 * available.
	 * @param beanFactory the source bean factory
	 * @return true if there are auto-config packages available
	 */
	public static boolean has(BeanFactory beanFactory) {
		return beanFactory.containsBean(BEAN) && !get(beanFactory).isEmpty();
	}

	/**
	 * Return the auto-configuration base packages for the given bean factory.
	 * @param beanFactory the source bean factory
	 * @return a list of auto-configuration packages
	 * @throws IllegalStateException if auto-configuration is not enabled
	 */
	public static List<String> get(BeanFactory beanFactory) {
		try {
			return beanFactory.getBean(BEAN, BasePackages.class).get();
		}
		catch (NoSuchBeanDefinitionException ex) {
			throw new IllegalStateException("Unable to retrieve @EnableAutoConfiguration base packages");
		}
	}

	/**
	 * Programmatically registers the auto-configuration package names. Subsequent
	 * invocations will add the given package names to those that have already been
	 * registered. You can use this method to manually define the base packages that will
	 * be used for a given {@link BeanDefinitionRegistry}. Generally it's recommended that
	 * you don't call this method directly, but instead rely on the default convention
	 * where the package name is set from your {@code @EnableAutoConfiguration}
	 * configuration class or classes.
	 * @param registry the bean definition registry
	 * @param packageNames the package names to set
	 */
	public static void register(BeanDefinitionRegistry registry, String... packageNames) {
		if (registry.containsBeanDefinition(BEAN)) {
			addBasePackages(registry.getBeanDefinition(BEAN), packageNames);
		}
		else {
			RootBeanDefinition beanDefinition = new RootBeanDefinition(BasePackages.class);
			beanDefinition.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
			addBasePackages(beanDefinition, packageNames);
			registry.registerBeanDefinition(BEAN, beanDefinition);
		}
	}

	private static void addBasePackages(BeanDefinition beanDefinition, String[] additionalBasePackages) {
		ConstructorArgumentValues constructorArgumentValues = beanDefinition.getConstructorArgumentValues();
		if (constructorArgumentValues.hasIndexedArgumentValue(0)) {
			ValueHolder indexedArgumentValue = constructorArgumentValues.getIndexedArgumentValue(0, String[].class);
			Assert.state(indexedArgumentValue != null, "'indexedArgumentValue' must not be null");
			String[] existingPackages = (String[]) indexedArgumentValue.getValue();
			Stream<String> existingPackagesStream = (existingPackages != null) ? Stream.of(existingPackages)
					: Stream.empty();
			constructorArgumentValues.addIndexedArgumentValue(0,
					Stream.concat(existingPackagesStream, Stream.of(additionalBasePackages))
						.distinct()
						.toArray(String[]::new));
		}
		else {
			constructorArgumentValues.addIndexedArgumentValue(0, additionalBasePackages);
		}
	}

	/**
	 * {@link ImportBeanDefinitionRegistrar} to store the base package from the importing
	 * configuration.
	 */
	static class Registrar implements ImportBeanDefinitionRegistrar, DeterminableImports {

		@Override
		public void registerBeanDefinitions(AnnotationMetadata metadata, BeanDefinitionRegistry registry) {
			register(registry, new PackageImports(metadata).getPackageNames().toArray(new String[0]));
		}

		@Override
		public Set<Object> determineImports(AnnotationMetadata metadata) {
			return Collections.singleton(new PackageImports(metadata));
		}

	}

	/**
	 * Wrapper for a package import.
	 */
	private static final class PackageImports {

		private final List<String> packageNames;

		PackageImports(AnnotationMetadata metadata) {
			AnnotationAttributes attributes = AnnotationAttributes
				.fromMap(metadata.getAnnotationAttributes(AutoConfigurationPackage.class.getName(), false));
			Assert.state(attributes != null, "'attributes' must not be null");
			List<String> packageNames = new ArrayList<>(Arrays.asList(attributes.getStringArray("basePackages")));
			for (Class<?> basePackageClass : attributes.getClassArray("basePackageClasses")) {
				packageNames.add(basePackageClass.getPackage().getName());
			}
			if (packageNames.isEmpty()) {
				packageNames.add(ClassUtils.getPackageName(metadata.getClassName()));
			}
			this.packageNames = Collections.unmodifiableList(packageNames);
		}

		List<String> getPackageNames() {
			return this.packageNames;
		}

		@Override
		public boolean equals(Object obj) {
			if (obj == null || getClass() != obj.getClass()) {
				return false;
			}
			return this.packageNames.equals(((PackageImports) obj).packageNames);
		}

		@Override
		public int hashCode() {
			return this.packageNames.hashCode();
		}

		@Override
		public String toString() {
			return "Package Imports " + this.packageNames;
		}

	}

	/**
	 * Holder for the base package (name may be null to indicate no scanning).
	 */
	static final class BasePackages {

		private final List<String> packages;

		private boolean loggedBasePackageInfo;

		BasePackages(String... names) {
			List<String> packages = new ArrayList<>();
			for (String name : names) {
				if (StringUtils.hasText(name)) {
					packages.add(name);
				}
			}
			this.packages = packages;
		}

		List<String> get() {
			if (!this.loggedBasePackageInfo) {
				if (this.packages.isEmpty()) {
					if (logger.isWarnEnabled()) {
						logger.warn("@EnableAutoConfiguration was declared on a class "
								+ "in the default package. Automatic @Repository and "
								+ "@Entity scanning is not enabled.");
					}
				}
				else {
					if (logger.isDebugEnabled()) {
						String packageNames = StringUtils.collectionToCommaDelimitedString(this.packages);
						logger.debug("@EnableAutoConfiguration was declared on a class in the package '" + packageNames
								+ "'. Automatic @Repository and @Entity scanning is enabled.");
					}
				}
				this.loggedBasePackageInfo = true;
			}
			return this.packages;
		}

	}

}