ConfigDataLocationResolvers Class — spring-boot Architecture

Source Code

core/spring-boot/src/main/java/org/springframework/boot/context/config/ConfigDataLocationResolvers.java lines 44–142

class ConfigDataLocationResolvers {

	private final List<ConfigDataLocationResolver<?>> resolvers;

	/**
	 * Create a new {@link ConfigDataLocationResolvers} instance.
	 * @param logFactory a {@link DeferredLogFactory} used to inject {@link Log} instances
	 * @param bootstrapContext the bootstrap context
	 * @param binder a binder providing values from the initial {@link Environment}
	 * @param resourceLoader {@link ResourceLoader} to load resource locations
	 * @param springFactoriesLoader to load {@link ConfigDataLocationResolver} instances
	 */
	ConfigDataLocationResolvers(DeferredLogFactory logFactory, ConfigurableBootstrapContext bootstrapContext,
			Binder binder, ResourceLoader resourceLoader, SpringFactoriesLoader springFactoriesLoader) {
		ArgumentResolver argumentResolver = ArgumentResolver.of(DeferredLogFactory.class, logFactory);
		argumentResolver = argumentResolver.and(Binder.class, binder);
		argumentResolver = argumentResolver.and(ResourceLoader.class, resourceLoader);
		argumentResolver = argumentResolver.and(ConfigurableBootstrapContext.class, bootstrapContext);
		argumentResolver = argumentResolver.and(BootstrapContext.class, bootstrapContext);
		argumentResolver = argumentResolver.and(BootstrapRegistry.class, bootstrapContext);
		argumentResolver = argumentResolver.andSupplied(Log.class, () -> {
			throw new IllegalArgumentException("Log types cannot be injected, please use DeferredLogFactory");
		});
		this.resolvers = reorder(springFactoriesLoader.load(ConfigDataLocationResolver.class, argumentResolver));
	}

	@SuppressWarnings("rawtypes")
	private List<ConfigDataLocationResolver<?>> reorder(List<ConfigDataLocationResolver> resolvers) {
		List<ConfigDataLocationResolver<?>> reordered = new ArrayList<>(resolvers.size());
		ConfigDataLocationResolver<?> standardConfigDataLocationResolver = null;
		for (ConfigDataLocationResolver<?> resolver : resolvers) {
			if (resolver instanceof StandardConfigDataLocationResolver) {
				standardConfigDataLocationResolver = resolver;
			}
			else {
				reordered.add(resolver);
			}
		}
		if (standardConfigDataLocationResolver != null) {
			reordered.add(standardConfigDataLocationResolver);
		}
		return Collections.unmodifiableList(reordered);
	}

	List<ConfigDataResolutionResult> resolve(ConfigDataLocationResolverContext context,
			@Nullable ConfigDataLocation location, @Nullable Profiles profiles) {
		if (location == null) {
			return Collections.emptyList();
		}
		for (ConfigDataLocationResolver<?> resolver : getResolvers()) {
			if (resolver.isResolvable(context, location)) {
				return resolve(resolver, context, location, profiles);
			}
		}
		throw new UnsupportedConfigDataLocationException(location);
	}

	private List<ConfigDataResolutionResult> resolve(ConfigDataLocationResolver<?> resolver,
			ConfigDataLocationResolverContext context, ConfigDataLocation location, @Nullable Profiles profiles) {
		List<ConfigDataResolutionResult> resolved = resolve(location, false, () -> resolver.resolve(context, location));
		if (profiles == null) {
			return resolved;
		}
		List<ConfigDataResolutionResult> profileSpecific = resolve(location, true,
				() -> resolver.resolveProfileSpecific(context, location, profiles));
		return merge(resolved, profileSpecific);
	}

	private List<ConfigDataResolutionResult> resolve(ConfigDataLocation location, boolean profileSpecific,
			Supplier<List<? extends ConfigDataResource>> resolveAction) {
		List<ConfigDataResource> resources = nonNullList(resolveAction.get());
		List<ConfigDataResolutionResult> resolved = new ArrayList<>(resources.size());
		for (ConfigDataResource resource : resources) {
			resolved.add(new ConfigDataResolutionResult(location, resource, profileSpecific));
		}
		return resolved;
	}

	@SuppressWarnings("unchecked")
	private <T> List<T> nonNullList(@Nullable List<? extends T> list) {
		return (list != null) ? (List<T>) list : Collections.emptyList();
	}

	private <T> List<T> merge(List<T> list1, List<T> list2) {
		List<T> merged = new ArrayList<>(list1.size() + list2.size());
		merged.addAll(list1);
		merged.addAll(list2);
		return merged;
	}

	/**
	 * Return the resolvers managed by this object.
	 * @return the resolvers
	 */
	List<ConfigDataLocationResolver<?>> getResolvers() {
		return this.resolvers;
	}

}