Polish "Allow customization of MongoClientSettings.Builder"

Closes gh-9341

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/mongo/MongoClientSettingsBuilderCustomizer.java

@@ -31,8 +31,8 @@ public interface MongoClientSettingsBuilderCustomizer {
 
 	/**
 	 * Customize the {@link Builder}.
-	 * @param settingsBuilder the builder to customize
+	 * @param clientSettingsBuilder the builder to customize
 	 */
-	void customize(Builder settingsBuilder);
+	void customize(Builder clientSettingsBuilder);
 
 }

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/mongo/ReactiveMongoClientFactory.java

@@ -54,7 +54,8 @@ public class ReactiveMongoClientFactory {
 			List<MongoClientSettingsBuilderCustomizer> builderCustomizers) {
 		this.properties = properties;
 		this.environment = environment;
-		this.builderCustomizers = builderCustomizers;
+		this.builderCustomizers = (builderCustomizers != null ? builderCustomizers
+				: Collections.emptyList());
 	}
 
 	/**
@@ -157,10 +158,8 @@ public class ReactiveMongoClientFactory {
 	}
 
 	private void customize(MongoClientSettings.Builder builder) {
-		if (this.builderCustomizers != null) {
-			for (MongoClientSettingsBuilderCustomizer customizer : this.builderCustomizers) {
-				customizer.customize(builder);
-			}
+		for (MongoClientSettingsBuilderCustomizer customizer : this.builderCustomizers) {
+			customizer.customize(builder);
 		}
 	}
 

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/mongo/MongoReactiveAutoConfigurationTests.java

@@ -20,7 +20,6 @@ import java.util.concurrent.TimeUnit;
 
 import com.mongodb.ReadPreference;
 import com.mongodb.async.client.MongoClientSettings;
-import com.mongodb.async.client.MongoClientSettings.Builder;
 import com.mongodb.connection.SocketSettings;
 import com.mongodb.connection.StreamFactory;
 import com.mongodb.connection.StreamFactoryFactory;
@@ -38,7 +37,6 @@ import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.BDDMockito.given;
 import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.verify;
 
 /**
  * Tests for {@link MongoReactiveAutoConfiguration}.
@@ -108,21 +106,6 @@ public class MongoReactiveAutoConfigurationTests {
 				.isSameAs(this.context.getBean("myStreamFactoryFactory"));
 	}
 
-	@Test
-	public void customizerGetsInvoked() {
-		this.context = new AnnotationConfigApplicationContext();
-		TestPropertyValues.of(
-				"spring.data.mongodb.uri:mongodb://localhost/test").applyTo(this.context);
-		this.context.register(PropertyPlaceholderAutoConfiguration.class,
-				MongoReactiveAutoConfiguration.class, MockCustomizerConfig.class);
-		this.context.refresh();
-		assertThat(this.context.getBeanNamesForType(MongoClient.class).length)
-				.isEqualTo(1);
-		MongoClientSettingsBuilderCustomizer customizer = this.context
-				.getBean(MongoClientSettingsBuilderCustomizer.class);
-		verify(customizer).customize(any(Builder.class));
-	}
-
 	@Test
 	public void customizerOverridesAutoConfig() {
 		this.context = new AnnotationConfigApplicationContext();
@@ -171,27 +154,13 @@ public class MongoReactiveAutoConfigurationTests {
 
 	}
 
-	@Configuration
-	static class MockCustomizerConfig {
-
-		@Bean
-		public MongoClientSettingsBuilderCustomizer customizer() {
-			return mock(MongoClientSettingsBuilderCustomizer.class);
-		}
-
-	}
-
 	@Configuration
 	static class SimpleCustomizerConfig {
 
 		@Bean
 		public MongoClientSettingsBuilderCustomizer customizer() {
-			return new MongoClientSettingsBuilderCustomizer() {
-				@Override
-				public void customize(MongoClientSettings.Builder settingsBuilder) {
-					settingsBuilder.applicationName("overridden-name");
-				}
-			};
+			return clientSettingsBuilder ->
+					clientSettingsBuilder.applicationName("overridden-name");
 		}
 
 	}

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/mongo/ReactiveMongoClientFactoryTests.java

@@ -17,6 +17,7 @@
 package org.springframework.boot.autoconfigure.mongo;
 
 import java.net.UnknownHostException;
+import java.util.Arrays;
 import java.util.List;
 
 import com.mongodb.MongoCredential;
@@ -32,6 +33,9 @@ import org.springframework.core.env.Environment;
 import org.springframework.mock.env.MockEnvironment;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
 
 /**
  * Tests for {@link ReactiveMongoClientFactory}.
@@ -148,14 +152,24 @@ public class ReactiveMongoClientFactoryTests {
 		assertServerAddress(allAddresses.get(0), "localhost", 4000);
 	}
 
+	@Test
+	public void customizerIsInvoked() {
+		MongoProperties properties = new MongoProperties();
+		MongoClientSettingsBuilderCustomizer customizer = mock(
+				MongoClientSettingsBuilderCustomizer.class);
+		createMongoClient(properties, this.environment, customizer);
+		verify(customizer).customize(any(MongoClientSettings.Builder.class));
+	}
+
 	private MongoClient createMongoClient(MongoProperties properties) {
 		return createMongoClient(properties, this.environment);
 	}
 
 	private MongoClient createMongoClient(MongoProperties properties,
-			Environment environment) {
-		return new ReactiveMongoClientFactory(properties, environment, null)
-				.createMongoClient(null);
+			Environment environment,
+			MongoClientSettingsBuilderCustomizer... customizers) {
+		return new ReactiveMongoClientFactory(properties, environment,
+				Arrays.asList(customizers)).createMongoClient(null);
 	}
 
 	private List<ServerAddress> extractServerAddresses(MongoClient client) {