DATACMNS-1368 - Add support for deferred repository initialization.

Both the XML and annotation based configuration sources now support a bootstrap mode configuration property that allow to configure whether repositories are eagerly initialized unless declared as lazy, initialized in a deferred way (just before the application context finishs bootstrapping) or entirely lazy (upon first usage, i.e. a method invocation).

We now register a custom AutowireCandidateResolver that will consider all injection points of lazy repositories lazy too. This will prevent them to accidentally trigger downstream infrastructure initialization.

src/test/java/org/springframework/data/repository/config/DefaultRepositoryConfigurationUnitTests.java

@@ -23,6 +23,7 @@ import lombok.Value;
 
 import java.util.Optional;
 
+import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.mockito.Mock;
@@ -45,6 +46,11 @@ public class DefaultRepositoryConfigurationUnitTests {
 
 	RepositoryConfigurationExtension extension = new SimplerRepositoryConfigurationExtension("factory", "module");
 
+	@Before
+	public void before() {
+		when(source.getBootstrapMode()).thenReturn(BootstrapMode.DEFAULT);
+	}
+
 	@Test
 	public void supportsBasicConfiguration() {
 

src/test/java/org/springframework/data/repository/config/EnableRepositories.java

@@ -51,4 +51,6 @@ public @interface EnableRepositories {
 	boolean considerNestedRepositories() default false;
 
 	boolean limitImplementationBasePackages() default true;
+
+	BootstrapMode bootstrapMode() default BootstrapMode.DEFAULT;
 }

src/test/java/org/springframework/data/repository/config/RepositoryComponentProviderUnitTests.java

@@ -49,7 +49,7 @@ public class RepositoryComponentProviderUnitTests {
 		RepositoryComponentProvider provider = new RepositoryComponentProvider(Collections.emptyList(), registry);
 		Set<BeanDefinition> components = provider.findCandidateComponents("org.springframework.data.repository.sample");
 
-		assertThat(components).hasSize(3);
+		assertThat(components).hasSize(4);
 		assertThat(components).extracting(BeanDefinition::getBeanClassName)
 				.contains(SampleAnnotatedRepository.class.getName());
 	}

src/test/java/org/springframework/data/repository/config/RepositoryConfigurationDelegateUnitTests.java

@@ -15,18 +15,29 @@
  */
 package org.springframework.data.repository.config;
 
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.hamcrest.CoreMatchers.*;
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertThat;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.mockito.Mock;
 import org.mockito.junit.MockitoJUnitRunner;
+import org.springframework.aop.TargetSource;
+import org.springframework.aop.framework.Advised;
+import org.springframework.beans.factory.ListableBeanFactory;
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.parsing.BeanComponentDefinition;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.context.annotation.ComponentScan.Filter;
+import org.springframework.context.annotation.FilterType;
 import org.springframework.context.support.GenericApplicationContext;
 import org.springframework.core.env.StandardEnvironment;
 import org.springframework.core.type.StandardAnnotationMetadata;
+import org.springframework.data.repository.config.RepositoryConfigurationDelegate.LazyRepositoryInjectionPointResolver;
+import org.springframework.data.repository.sample.AddressRepository;
+import org.springframework.data.repository.sample.AddressRepositoryClient;
 import org.springframework.data.repository.sample.ProductRepository;
 
 /**
@@ -35,7 +46,7 @@ import org.springframework.data.repository.sample.ProductRepository;
  * @author Oliver Gierke
  * @soundtrack Richard Spaven - Tribute (Whole Other*)
  */
-@RunWith(MockitoJUnitRunner.class)
+@RunWith(MockitoJUnitRunner.Silent.class)
 public class RepositoryConfigurationDelegateUnitTests {
 
 	@Mock RepositoryConfigurationExtension extension;
@@ -61,6 +72,51 @@ public class RepositoryConfigurationDelegateUnitTests {
 		}
 	}
 
+	@Test // DATACMNS-1368
+	public void registersLazyAutowireCandidateResolver() {
+		assertLazyRepositoryBeanSetup(LazyConfig.class);
+	}
+
+	@Test // DATACMNS-1368
+	public void registersDeferredRepositoryInitializationListener() {
+
+		ListableBeanFactory beanFactory = assertLazyRepositoryBeanSetup(DeferredConfig.class);
+
+		assertThat(beanFactory.getBeanNamesForType(DeferredRepositoryInitializationListener.class)).isNotEmpty();
+
+	}
+
+	private static ListableBeanFactory assertLazyRepositoryBeanSetup(Class<?> configClass) {
+
+		StandardEnvironment environment = new StandardEnvironment();
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(configClass);
+
+		assertThat(context.getDefaultListableBeanFactory().getAutowireCandidateResolver())
+				.isInstanceOf(LazyRepositoryInjectionPointResolver.class);
+
+		AddressRepositoryClient client = context.getBean(AddressRepositoryClient.class);
+		AddressRepository repository = client.getRepository();
+
+		assertThat(Advised.class.isInstance(repository)).isTrue();
+
+		TargetSource targetSource = Advised.class.cast(repository).getTargetSource();
+		assertThat(targetSource).isNotNull();
+
+		return context.getDefaultListableBeanFactory();
+	}
+
 	@EnableRepositories(basePackageClasses = ProductRepository.class)
 	static class TestConfig {}
+
+	@ComponentScan(basePackageClasses = AddressRepository.class)
+	@EnableRepositories(basePackageClasses = AddressRepository.class,
+			includeFilters = @Filter(type = FilterType.ASSIGNABLE_TYPE, classes = AddressRepository.class),
+			bootstrapMode = BootstrapMode.LAZY)
+	static class LazyConfig {}
+
+	@ComponentScan(basePackageClasses = AddressRepository.class)
+	@EnableRepositories(basePackageClasses = AddressRepository.class,
+			includeFilters = @Filter(type = FilterType.ASSIGNABLE_TYPE, classes = AddressRepository.class),
+			bootstrapMode = BootstrapMode.DEFERRED)
+	static class DeferredConfig {}
 }

src/test/java/org/springframework/data/repository/sample/AddressRepository.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.repository.sample;
+
+import org.springframework.data.repository.Repository;
+import org.springframework.data.repository.sample.AddressRepository.Address;
+
+/**
+ * @author Oliver Gierke
+ */
+public interface AddressRepository extends Repository<Address, Long> {
+
+	static class Address {}
+}

src/test/java/org/springframework/data/repository/sample/AddressRepositoryClient.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.repository.sample;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+import org.springframework.stereotype.Component;
+
+/**
+ * @author Oliver Gierke
+ */
+@Component
+@RequiredArgsConstructor
+public class AddressRepositoryClient {
+
+	private final @Getter AddressRepository repository;
+}