AutoConfigurationGroup Class — spring-boot Architecture

Source Code

core/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/AutoConfigurationImportSelector.java lines 431–539

	private static final class AutoConfigurationGroup
			implements DeferredImportSelector.Group, BeanClassLoaderAware, BeanFactoryAware, ResourceLoaderAware {

		private final Map<String, AnnotationMetadata> entries = new LinkedHashMap<>();

		private final List<AutoConfigurationEntry> autoConfigurationEntries = new ArrayList<>();

		@SuppressWarnings("NullAway.Init")
		private ClassLoader beanClassLoader;

		@SuppressWarnings("NullAway.Init")
		private BeanFactory beanFactory;

		@SuppressWarnings("NullAway.Init")
		private ResourceLoader resourceLoader;

		private @Nullable AutoConfigurationMetadata autoConfigurationMetadata;

		private @Nullable AutoConfigurationReplacements autoConfigurationReplacements;

		@Override
		public void setBeanClassLoader(ClassLoader classLoader) {
			this.beanClassLoader = classLoader;
		}

		@Override
		public void setBeanFactory(BeanFactory beanFactory) {
			this.beanFactory = beanFactory;
		}

		@Override
		public void setResourceLoader(ResourceLoader resourceLoader) {
			this.resourceLoader = resourceLoader;
		}

		@Override
		public void process(AnnotationMetadata annotationMetadata, DeferredImportSelector deferredImportSelector) {
			Assert.state(deferredImportSelector instanceof AutoConfigurationImportSelector,
					() -> String.format("Only %s implementations are supported, got %s",
							AutoConfigurationImportSelector.class.getSimpleName(),
							deferredImportSelector.getClass().getName()));
			AutoConfigurationImportSelector autoConfigurationImportSelector = (AutoConfigurationImportSelector) deferredImportSelector;
			AutoConfigurationReplacements autoConfigurationReplacements = autoConfigurationImportSelector
				.getAutoConfigurationReplacements();
			Assert.state(
					this.autoConfigurationReplacements == null
							|| this.autoConfigurationReplacements.equals(autoConfigurationReplacements),
					"Auto-configuration replacements must be the same for each call to process");
			this.autoConfigurationReplacements = autoConfigurationReplacements;
			AutoConfigurationEntry autoConfigurationEntry = autoConfigurationImportSelector
				.getAutoConfigurationEntry(annotationMetadata);
			this.autoConfigurationEntries.add(autoConfigurationEntry);
			for (String importClassName : autoConfigurationEntry.getConfigurations()) {
				this.entries.putIfAbsent(importClassName, annotationMetadata);
			}
		}

		@Override
		public Iterable<Entry> selectImports() {
			if (this.autoConfigurationEntries.isEmpty()) {
				return Collections.emptyList();
			}
			Set<String> allExclusions = this.autoConfigurationEntries.stream()
				.map(AutoConfigurationEntry::getExclusions)
				.flatMap(Collection::stream)
				.collect(Collectors.toSet());
			Set<String> processedConfigurations = this.autoConfigurationEntries.stream()
				.map(AutoConfigurationEntry::getConfigurations)
				.flatMap(Collection::stream)
				.collect(Collectors.toCollection(LinkedHashSet::new));
			processedConfigurations.removeAll(allExclusions);
			return sortAutoConfigurations(processedConfigurations, getAutoConfigurationMetadata()).stream()
				.map(this::getEntry)
				.toList();
		}

		private Entry getEntry(String importClassName) {
			AnnotationMetadata metadata = this.entries.get(importClassName);
			Assert.state(metadata != null, "'metadata' must not be null");
			return new Entry(metadata, importClassName);
		}

		private AutoConfigurationMetadata getAutoConfigurationMetadata() {
			if (this.autoConfigurationMetadata == null) {
				this.autoConfigurationMetadata = AutoConfigurationMetadataLoader.loadMetadata(this.beanClassLoader);
			}
			return this.autoConfigurationMetadata;
		}

		private List<String> sortAutoConfigurations(Set<String> configurations,
				AutoConfigurationMetadata autoConfigurationMetadata) {
			Assert.state(this.autoConfigurationReplacements != null,
					"'autoConfigurationReplacements' must not be null");
			return new AutoConfigurationSorter(getMetadataReaderFactory(), autoConfigurationMetadata,
					this.autoConfigurationReplacements::replace)
				.getInPriorityOrder(configurations);
		}

		private MetadataReaderFactory getMetadataReaderFactory() {
			try {
				return this.beanFactory.getBean(SharedMetadataReaderFactoryContextInitializer.BEAN_NAME,
						MetadataReaderFactory.class);
			}
			catch (NoSuchBeanDefinitionException ex) {
				return new CachingMetadataReaderFactory(this.resourceLoader);
			}
		}

	}