Allow chained BeanRegistry registration

Add a `register(BeanRegistry registry)` method to `BeanRegistry`
to allow registration chaining.

Author: philwebb

spring-beans/src/main/java/org/springframework/beans/factory/BeanRegistry.java

@@ -77,6 +77,13 @@ public interface BeanRegistry {
 	 */
 	<T> void registerBean(String name, Class<T> beanClass, Consumer<Spec<T>> customizer);
 
+	/**
+	 * Register beans using given {@link BeanRegistrar}.
+	 * @param registrar the bean registrar that will be called to register
+	 * additional beans
+	 */
+	void register(BeanRegistrar registrar);
+
 	/**
 	 * Specification for customizing a bean.
 	 * @param <T> the bean type

spring-beans/src/main/java/org/springframework/beans/factory/support/BeanRegistryAdapter.java

@@ -31,6 +31,8 @@
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.config.BeanDefinitionCustomizer;
 import org.springframework.core.ResolvableType;
+import org.springframework.core.env.Environment;
+import org.springframework.util.Assert;
 import org.springframework.util.MultiValueMap;
 
 /**
@@ -46,21 +48,26 @@ public class BeanRegistryAdapter implements BeanRegistry {
 
 	private final ListableBeanFactory beanFactory;
 
+	private final Environment environment;
+
 	private final Class<? extends BeanRegistrar> beanRegistrarClass;
 
 	private final @Nullable MultiValueMap<String, BeanDefinitionCustomizer> customizers;
 
 
 	public BeanRegistryAdapter(BeanDefinitionRegistry beanRegistry, ListableBeanFactory beanFactory,
-			Class<? extends BeanRegistrar> beanRegistrarClass) {
-		this(beanRegistry, beanFactory, beanRegistrarClass, null);
+			Environment environment, Class<? extends BeanRegistrar> beanRegistrarClass) {
+
+		this(beanRegistry, beanFactory, environment, beanRegistrarClass, null);
 	}
 
 	public BeanRegistryAdapter(BeanDefinitionRegistry beanRegistry, ListableBeanFactory beanFactory,
-			Class<? extends BeanRegistrar> beanRegistrarClass, @Nullable MultiValueMap<String, BeanDefinitionCustomizer> customizers) {
+			Environment environment, Class<? extends BeanRegistrar> beanRegistrarClass,
+			@Nullable MultiValueMap<String, BeanDefinitionCustomizer> customizers) {
 
 		this.beanRegistry = beanRegistry;
 		this.beanFactory = beanFactory;
+		this.environment = environment;
 		this.beanRegistrarClass = beanRegistrarClass;
 		this.customizers = customizers;
 	}
@@ -102,6 +109,12 @@ public <T> void registerBean(String name, Class<T> beanClass, Consumer<Spec<T>>
 		this.beanRegistry.registerBeanDefinition(name, beanDefinition);
 	}
 
+	@Override
+	public void register(BeanRegistrar registrar) {
+		Assert.notNull(registrar, "'registrar' must not be null");
+		registrar.register(this, this.environment);
+	}
+
 
 	/**
 	 * {@link RootBeanDefinition} subclass for {@code #registerBean} based

spring-beans/src/test/java/org/springframework/beans/factory/support/BeanRegistryAdapterTests.java

@@ -27,6 +27,7 @@
 import org.springframework.core.env.StandardEnvironment;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.*;
 
 /**
  * Tests for {@link BeanRegistryAdapter}.
@@ -41,103 +42,103 @@ public class BeanRegistryAdapterTests {
 
 	@Test
 	void defaultBackgroundInit() {
-		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, DefaultBeanRegistrar.class);
+		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, this.env, DefaultBeanRegistrar.class);
 		new DefaultBeanRegistrar().register(adapter, env);
 		AbstractBeanDefinition beanDefinition = (AbstractBeanDefinition) this.beanFactory.getBeanDefinition("foo");
 		assertThat(beanDefinition.isBackgroundInit()).isFalse();
 	}
 
 	@Test
 	void enableBackgroundInit() {
-		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, BackgroundInitBeanRegistrar.class);
+		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, this.env, BackgroundInitBeanRegistrar.class);
 		new BackgroundInitBeanRegistrar().register(adapter, env);
 		AbstractBeanDefinition beanDefinition = (AbstractBeanDefinition) this.beanFactory.getBeanDefinition("foo");
 		assertThat(beanDefinition.isBackgroundInit()).isTrue();
 	}
 
 	@Test
 	void defaultDescription() {
-		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, DefaultBeanRegistrar.class);
+		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, this.env, DefaultBeanRegistrar.class);
 		new DefaultBeanRegistrar().register(adapter, env);
 		BeanDefinition beanDefinition = this.beanFactory.getBeanDefinition("foo");
 		assertThat(beanDefinition.getDescription()).isNull();
 	}
 
 	@Test
 	void customDescription() {
-		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, CustomDescriptionBeanRegistrar.class);
+		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, this.env, CustomDescriptionBeanRegistrar.class);
 		new CustomDescriptionBeanRegistrar().register(adapter, env);
 		BeanDefinition beanDefinition = this.beanFactory.getBeanDefinition("foo");
 		assertThat(beanDefinition.getDescription()).isEqualTo("custom");
 	}
 
 	@Test
 	void defaultFallback() {
-		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, DefaultBeanRegistrar.class);
+		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, this.env, DefaultBeanRegistrar.class);
 		new DefaultBeanRegistrar().register(adapter, env);
 		BeanDefinition beanDefinition = this.beanFactory.getBeanDefinition("foo");
 		assertThat(beanDefinition.isFallback()).isFalse();
 	}
 
 	@Test
 	void enableFallback() {
-		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, FallbackBeanRegistrar.class);
+		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, this.env, FallbackBeanRegistrar.class);
 		new FallbackBeanRegistrar().register(adapter, env);
 		BeanDefinition beanDefinition = this.beanFactory.getBeanDefinition("foo");
 		assertThat(beanDefinition.isFallback()).isTrue();
 	}
 
 	@Test
 	void defaultRole() {
-		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, DefaultBeanRegistrar.class);
+		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, this.env, DefaultBeanRegistrar.class);
 		new DefaultBeanRegistrar().register(adapter, env);
 		BeanDefinition beanDefinition = this.beanFactory.getBeanDefinition("foo");
 		assertThat(beanDefinition.getRole()).isEqualTo(AbstractBeanDefinition.ROLE_APPLICATION);
 	}
 
 	@Test
 	void infrastructureRole() {
-		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, InfrastructureBeanRegistrar.class);
+		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, this.env, InfrastructureBeanRegistrar.class);
 		new InfrastructureBeanRegistrar().register(adapter, env);
 		BeanDefinition beanDefinition = this.beanFactory.getBeanDefinition("foo");
 		assertThat(beanDefinition.getRole()).isEqualTo(AbstractBeanDefinition.ROLE_INFRASTRUCTURE);
 	}
 
 	@Test
 	void defaultLazyInit() {
-		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, DefaultBeanRegistrar.class);
+		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, this.env, DefaultBeanRegistrar.class);
 		new DefaultBeanRegistrar().register(adapter, env);
 		AbstractBeanDefinition beanDefinition = (AbstractBeanDefinition) this.beanFactory.getBeanDefinition("foo");
 		assertThat(beanDefinition.isLazyInit()).isFalse();
 	}
 
 	@Test
 	void enableLazyInit() {
-		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, LazyInitBeanRegistrar.class);
+		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, this.env, LazyInitBeanRegistrar.class);
 		new LazyInitBeanRegistrar().register(adapter, env);
 		AbstractBeanDefinition beanDefinition = (AbstractBeanDefinition) this.beanFactory.getBeanDefinition("foo");
 		assertThat(beanDefinition.isLazyInit()).isTrue();
 	}
 
 	@Test
 	void defaultAutowirable() {
-		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, DefaultBeanRegistrar.class);
+		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, this.env, DefaultBeanRegistrar.class);
 		new DefaultBeanRegistrar().register(adapter, env);
 		AbstractBeanDefinition beanDefinition = (AbstractBeanDefinition) this.beanFactory.getBeanDefinition("foo");
 		assertThat(beanDefinition.isAutowireCandidate()).isTrue();
 	}
 
 	@Test
 	void notAutowirable() {
-		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, NotAutowirableBeanRegistrar.class);
+		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, this.env, NotAutowirableBeanRegistrar.class);
 		new NotAutowirableBeanRegistrar().register(adapter, env);
 		AbstractBeanDefinition beanDefinition = (AbstractBeanDefinition) this.beanFactory.getBeanDefinition("foo");
 		assertThat(beanDefinition.isAutowireCandidate()).isFalse();
 	}
 
 	@Test
 	void defaultOrder() {
-		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, DefaultBeanRegistrar.class);
+		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, this.env, DefaultBeanRegistrar.class);
 		new DefaultBeanRegistrar().register(adapter, env);
 		AbstractBeanDefinition beanDefinition = (AbstractBeanDefinition) this.beanFactory.getBeanDefinition("foo");
 		Integer order = (Integer)beanDefinition.getAttribute(AbstractBeanDefinition.ORDER_ATTRIBUTE);
@@ -146,7 +147,7 @@ void defaultOrder() {
 
 	@Test
 	void customOrder() {
-		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, CustomOrderBeanRegistrar.class);
+		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, this.env, CustomOrderBeanRegistrar.class);
 		new CustomOrderBeanRegistrar().register(adapter, env);
 		AbstractBeanDefinition beanDefinition = (AbstractBeanDefinition) this.beanFactory.getBeanDefinition("foo");
 		Integer order = (Integer)beanDefinition.getAttribute(AbstractBeanDefinition.ORDER_ATTRIBUTE);
@@ -155,54 +156,62 @@ void customOrder() {
 
 	@Test
 	void defaultPrimary() {
-		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, DefaultBeanRegistrar.class);
+		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, this.env, DefaultBeanRegistrar.class);
 		new DefaultBeanRegistrar().register(adapter, env);
 		BeanDefinition beanDefinition = this.beanFactory.getBeanDefinition("foo");
 		assertThat(beanDefinition.isPrimary()).isFalse();
 	}
 
 	@Test
 	void enablePrimary() {
-		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, PrimaryBeanRegistrar.class);
+		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, this.env, PrimaryBeanRegistrar.class);
 		new PrimaryBeanRegistrar().register(adapter, env);
 		BeanDefinition beanDefinition = this.beanFactory.getBeanDefinition("foo");
 		assertThat(beanDefinition.isPrimary()).isTrue();
 	}
 
 	@Test
 	void defaultScope() {
-		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, DefaultBeanRegistrar.class);
+		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, this.env, DefaultBeanRegistrar.class);
 		new DefaultBeanRegistrar().register(adapter, env);
 		BeanDefinition beanDefinition = this.beanFactory.getBeanDefinition("foo");
 		assertThat(beanDefinition.getScope()).isEqualTo(AbstractBeanDefinition.SCOPE_DEFAULT);
 	}
 
 	@Test
 	void prototypeScope() {
-		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, PrototypeBeanRegistrar.class);
+		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, this.env, PrototypeBeanRegistrar.class);
 		new PrototypeBeanRegistrar().register(adapter, env);
 		BeanDefinition beanDefinition = this.beanFactory.getBeanDefinition("foo");
 		assertThat(beanDefinition.getScope()).isEqualTo(AbstractBeanDefinition.SCOPE_PROTOTYPE);
 	}
 
 	@Test
 	void defaultSupplier() {
-		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, DefaultBeanRegistrar.class);
+		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, this.env, DefaultBeanRegistrar.class);
 		new DefaultBeanRegistrar().register(adapter, env);
 		AbstractBeanDefinition beanDefinition = (AbstractBeanDefinition)this.beanFactory.getBeanDefinition("foo");
 		assertThat(beanDefinition.getInstanceSupplier()).isNull();
 	}
 
 	@Test
 	void customSupplier() {
-		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, SupplierBeanRegistrar.class);
+		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, this.env, SupplierBeanRegistrar.class);
 		new SupplierBeanRegistrar().register(adapter, env);
 		AbstractBeanDefinition beanDefinition = (AbstractBeanDefinition)this.beanFactory.getBeanDefinition("foo");
 		Supplier<?> supplier = beanDefinition.getInstanceSupplier();
 		assertThat(supplier).isNotNull();
 		assertThat(supplier.get()).isNotNull().isInstanceOf(Foo.class);
 	}
 
+	@Test
+	void registerViaAnotherRegistrar() {
+		BeanRegistryAdapter adapter = new BeanRegistryAdapter(this.beanFactory, this.beanFactory, this.env, DefaultBeanRegistrar.class);
+		BeanRegistrar registrar = (registry, env) -> registry.register(new DefaultBeanRegistrar());
+		registrar.register(adapter, env);
+		assertThat(this.beanFactory.getBeanDefinition("foo")).isNotNull();
+	}
+
 
 	private static class DefaultBeanRegistrar implements BeanRegistrar {
 

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassBeanDefinitionReader.java

@@ -409,7 +409,7 @@ private void loadBeanDefinitionsFromBeanRegistrars(Set<BeanRegistrar> registrars
 				"Cannot support bean registrars since " + this.registry.getClass().getName() +
 						" does not implement BeanDefinitionRegistry");
 		registrars.forEach(registrar -> registrar.register(new BeanRegistryAdapter(this.registry,
-				(ListableBeanFactory) this.registry, registrar.getClass()), this.environment));
+				(ListableBeanFactory) this.registry, this.environment, registrar.getClass()), this.environment));
 	}