GH-1691 - Fail early if bookmark setup is enabled without a bookmark manager.

This change adds a bean through `@EnableBookmarkManagement` that asserts
the presence of a bean implementing
`org.springframework.data.neo4j.bookmark.BookmarkManager`. Thus the
context will fail to start up early when the user assumes that the
combination of `@EnableBookmarkManagement` and `@UseBookmark` is enough
and not only on the latest point in time possible.

This closes #1691.

spring-data-neo4j/src/main/java/org/springframework/data/neo4j/bookmark/BookmarkManagementConfiguration.java

@@ -15,10 +15,14 @@
  */
 package org.springframework.data.neo4j.bookmark;
 
+import org.springframework.beans.factory.NoSuchBeanDefinitionException;
+import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.beans.factory.config.BeanDefinition;
+import org.springframework.context.ApplicationListener;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Role;
+import org.springframework.context.event.ContextRefreshedEvent;
 
 /**
  * Configuration used by @{@link org.springframework.data.neo4j.annotation.EnableBookmarkManagement}
@@ -33,6 +37,7 @@ import org.springframework.context.annotation.Role;
  * provide the BookmarkManager bean.
  *
  * @author Frantisek Hartman
+ * @author Michael J. Simons
  */
 @Configuration
 public class BookmarkManagementConfiguration {
@@ -52,4 +57,33 @@ public class BookmarkManagementConfiguration {
 		return new BookmarkInterceptor();
 	}
 
+	@Bean
+	@Role(BeanDefinition.ROLE_INFRASTRUCTURE)
+	public BookmarkManagerContextValidator bookmarkManagerContextValidator(
+			ObjectProvider<BookmarkManager> bookmarkManagerProvider) {
+		return new BookmarkManagerContextValidator(bookmarkManagerProvider);
+	}
+
+	/**
+	 * A helper class that asserts the presence of a {@link BookmarkManager} on startup.
+	 */
+	static class BookmarkManagerContextValidator implements ApplicationListener<ContextRefreshedEvent> {
+
+		private final ObjectProvider<BookmarkManager> bookmarkManagerProvider;
+
+		public BookmarkManagerContextValidator(ObjectProvider<BookmarkManager> bookmarkManagerProvider) {
+			this.bookmarkManagerProvider = bookmarkManagerProvider;
+		}
+
+		@Override
+		public void onApplicationEvent(ContextRefreshedEvent event) {
+			try {
+				bookmarkManagerProvider.getObject();
+			} catch (NoSuchBeanDefinitionException e) {
+				throw new IllegalStateException(
+						"Bookmark management has been enabled via `@EnableBookmarkManagement` but no bean implementing `org.springframework.data.neo4j.bookmark.BookmarkManager` has been provided.\n"
+						+ "Preventing the start of the context as all `@UseBookmark` annotated methods would fail. Please provide a bookmark manager.");
+			}
+		}
+	}
 }

spring-data-neo4j/src/test/java/org/springframework/data/neo4j/bookmark/BookmarkManagementConfigurationTests.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2011-2021 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
+ *
+ *      https://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.neo4j.bookmark;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
+
+import java.util.Collection;
+import java.util.Collections;
+
+import org.junit.Test;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.data.neo4j.annotation.EnableBookmarkManagement;
+import org.springframework.transaction.annotation.EnableTransactionManagement;
+
+/**
+ * @author Michael J. Simons
+ */
+public class BookmarkManagementConfigurationTests {
+
+	@Test // GH-1691
+	public void bookmarkManagerShouldBeRequired() {
+
+		assertThatIllegalStateException().isThrownBy(() -> new AnnotationConfigApplicationContext(BookmarkManagementConfiguration.class))
+				.withMessageStartingWith("Bookmark management has been enabled via `@EnableBookmarkManagement` but no bean implementing `org.springframework.data.neo4j.bookmark.BookmarkManager` has been provided.");
+	}
+
+	@Test // GH-1691
+	public void bookmarkManagerShouldBeRecognized() {
+
+		try(ConfigurableApplicationContext ctx = new AnnotationConfigApplicationContext(BookmarkManagementConfiguration.class, BookmarkManagerConfiguration.class)) {
+			assertThat(ctx.getBean(BookmarkInterceptor.class)).isNotNull();
+			assertThat(ctx.getBean(BeanFactoryBookmarkOperationAdvisor.class)).isNotNull();
+			assertThat(ctx.getBean(
+					org.springframework.data.neo4j.bookmark.BookmarkManagementConfiguration.BookmarkManagerContextValidator.class)).isNotNull();
+		}
+	}
+
+	@Configuration
+	@EnableBookmarkManagement
+	@EnableTransactionManagement
+	static class BookmarkManagementConfiguration {
+	}
+
+	@Configuration
+	static class BookmarkManagerConfiguration {
+		@Bean
+		public BookmarkManager bookmarkManager() {
+			return new BookmarkManager() {
+				@Override
+				public Collection<String> getBookmarks() {
+					return Collections.emptyList();
+				}
+
+				@Override
+				public void storeBookmark(String bookmark, Collection<String> previous) {
+				}
+			};
+		}
+	}
+}

spring-data-neo4j/src/test/java/org/springframework/data/neo4j/bookmark/BookmarkManagementTests.java

@@ -20,6 +20,8 @@ import static org.assertj.core.api.Assertions.*;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.data.neo4j.annotation.EnableBookmarkManagement;
@@ -143,7 +145,7 @@ public class BookmarkManagementTests {
 
 	@Configuration
 	@EnableBookmarkManagement
-	@EnableTransactionManagement()
+	@EnableTransactionManagement
 	static class BookmarkManagementConfiguration {
 
 		@Bean
@@ -166,6 +168,11 @@ public class BookmarkManagementTests {
 			return new UseBookmarkWrapperOnClassBean();
 		}
 
+		@Bean
+		public BookmarkManager bookmarkManager() {
+			return new CaffeineBookmarkManager();
+		}
+
 		@Bean
 		public UseBookmarkWrapperOnMethodBean useBookmarkWrapperOnMethodBean() {
 			return new UseBookmarkWrapperOnMethodBean();