ImportAutoConfigurationImportSelector Class — spring-boot Architecture

Source Code

core/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/ImportAutoConfigurationImportSelector.java lines 54–179

class ImportAutoConfigurationImportSelector extends AutoConfigurationImportSelector implements DeterminableImports {

	private static final String OPTIONAL_PREFIX = "optional:";

	private static final Set<String> ANNOTATION_NAMES;

	static {
		Set<String> names = new LinkedHashSet<>();
		names.add(ImportAutoConfiguration.class.getName());
		names.add("org.springframework.boot.autoconfigure.test.ImportAutoConfiguration");
		ANNOTATION_NAMES = Collections.unmodifiableSet(names);
	}

	@Override
	public Set<Object> determineImports(AnnotationMetadata metadata) {
		List<String> candidateConfigurations = getCandidateConfigurations(metadata, null);
		Set<String> result = new LinkedHashSet<>(candidateConfigurations);
		result.removeAll(getExclusions(metadata, null));
		return Collections.unmodifiableSet(result);
	}

	@Override
	protected @Nullable AnnotationAttributes getAttributes(AnnotationMetadata metadata) {
		return null;
	}

	@Override
	protected List<String> getCandidateConfigurations(AnnotationMetadata metadata,
			@Nullable AnnotationAttributes attributes) {
		List<String> candidates = new ArrayList<>();
		Map<Class<?>, List<Annotation>> annotations = getAnnotations(metadata);
		annotations.forEach(
				(source, sourceAnnotations) -> collectCandidateConfigurations(source, sourceAnnotations, candidates));
		return candidates;
	}

	private void collectCandidateConfigurations(Class<?> source, List<Annotation> annotations,
			List<String> candidates) {
		for (Annotation annotation : annotations) {
			candidates.addAll(getConfigurationsForAnnotation(source, annotation));
		}
	}

	private Collection<String> getConfigurationsForAnnotation(Class<?> source, Annotation annotation) {
		String[] classes = (String[]) AnnotationUtils.getAnnotationAttributes(annotation, true).get("classes");
		if (classes != null && classes.length > 0) {
			return Arrays.asList(classes);
		}
		return loadFactoryNames(source).stream().map(this::mapFactoryName).filter(Objects::nonNull).toList();
	}

	private @Nullable String mapFactoryName(String name) {
		if (!name.startsWith(OPTIONAL_PREFIX)) {
			return name;
		}
		name = name.substring(OPTIONAL_PREFIX.length());
		return (!present(name)) ? null : name;
	}

	private boolean present(String className) {
		String resourcePath = ClassUtils.convertClassNameToResourcePath(className) + ".class";
		return new ClassPathResource(resourcePath).exists();
	}

	protected Collection<String> loadFactoryNames(Class<?> source) {
		return ImportCandidates.load(source, getBeanClassLoader()).getCandidates();
	}

	@Override
	protected Set<String> getExclusions(AnnotationMetadata metadata, @Nullable AnnotationAttributes attributes) {
		Set<String> exclusions = new LinkedHashSet<>();
		Class<?> source = ClassUtils.resolveClassName(metadata.getClassName(), getBeanClassLoader());
		for (String annotationName : ANNOTATION_NAMES) {
			AnnotationAttributes merged = AnnotatedElementUtils.getMergedAnnotationAttributes(source, annotationName);
			Class<?>[] exclude = (merged != null) ? merged.getClassArray("exclude") : null;
			if (exclude != null) {
				for (Class<?> excludeClass : exclude) {
					exclusions.add(excludeClass.getName());
				}
			}
		}
		for (List<Annotation> annotations : getAnnotations(metadata).values()) {
			for (Annotation annotation : annotations) {
				String[] exclude = (String[]) AnnotationUtils.getAnnotationAttributes(annotation, true).get("exclude");
				if (!ObjectUtils.isEmpty(exclude)) {
					exclusions.addAll(Arrays.asList(exclude));
				}
			}
		}
		exclusions.addAll(getExcludeAutoConfigurationsProperty());
		return exclusions;
	}

	protected final Map<Class<?>, List<Annotation>> getAnnotations(AnnotationMetadata metadata) {
		MultiValueMap<Class<?>, Annotation> annotations = new LinkedMultiValueMap<>();
		Class<?> source = ClassUtils.resolveClassName(metadata.getClassName(), getBeanClassLoader());
		collectAnnotations(source, annotations, new HashSet<>());
		return Collections.unmodifiableMap(annotations);
	}

	private void collectAnnotations(@Nullable Class<?> source, MultiValueMap<Class<?>, Annotation> annotations,
			HashSet<Class<?>> seen) {
		if (source != null && seen.add(source)) {
			for (Annotation annotation : source.getDeclaredAnnotations()) {
				if (!AnnotationUtils.isInJavaLangAnnotationPackage(annotation)) {
					if (ANNOTATION_NAMES.contains(annotation.annotationType().getName())) {
						annotations.add(source, annotation);
					}
					collectAnnotations(annotation.annotationType(), annotations, seen);
				}
			}
			collectAnnotations(source.getSuperclass(), annotations, seen);
		}
	}

	@Override
	public int getOrder() {
		return super.getOrder() - 1;
	}

	@Override
	protected void handleInvalidExcludes(List<String> invalidExcludes) {
		// Ignore for test
	}

}