Allow to customize Cluster.Builder rather than Cluster

Rework cb3d14a so that the customizer operates on the Builder rather than
the Cluster. The former exposes many more options.

See gh-7320
Closes gh-7669

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/cassandra/CassandraAutoConfiguration.java

@@ -40,6 +40,8 @@ import org.springframework.util.StringUtils;
  *
  * @author Julien Dubois
  * @author Phillip Webb
+ * @author Eddú Meléndez
+ * @author Stephane Nicoll
  * @since 1.3.0
  */
 @Configuration
@@ -49,12 +51,13 @@ public class CassandraAutoConfiguration {
 
 	private final CassandraProperties properties;
 
-	private final List<ClusterCustomizer> clusterCustomizers;
+	private final List<ClusterBuilderCustomizer> builderCustomizers;
 
 	public CassandraAutoConfiguration(CassandraProperties properties,
-			ObjectProvider<List<ClusterCustomizer>> clusterCustomizersProvider) {
+			ObjectProvider<List<ClusterBuilderCustomizer>> builderCustomizersProvider) {
 		this.properties = properties;
-		this.clusterCustomizers = clusterCustomizersProvider.getIfAvailable();
+		this.builderCustomizers = builderCustomizersProvider
+				.getIfAvailable();
 	}
 
 	@Bean
@@ -90,15 +93,14 @@ public class CassandraAutoConfiguration {
 		String points = properties.getContactPoints();
 		builder.addContactPoints(StringUtils.commaDelimitedListToStringArray(points));
 
-		Cluster cluster = builder.build();
-		customize(cluster);
-		return cluster;
+		customize(builder);
+		return builder.build();
 	}
 
-	private void customize(Cluster cluster) {
-		if (this.clusterCustomizers != null) {
-			for (ClusterCustomizer customizer : this.clusterCustomizers) {
-				customizer.customize(cluster);
+	private void customize(Cluster.Builder builder) {
+		if (this.builderCustomizers != null) {
+			for (ClusterBuilderCustomizer customizer : this.builderCustomizers) {
+				customizer.customize(builder);
 			}
 		}
 	}

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/cassandra/ClusterBuilderCustomizer.java

@@ -20,18 +20,17 @@ import com.datastax.driver.core.Cluster;
 
 /**
  * Callback interface that can be implemented by beans wishing to customize the
- * {@link Cluster} before it is fully initialized, in particular to tune its
- * configuration.
+ * {@link Cluster} via {@link Cluster.Builder} retaining its default auto-configuration.
  *
  * @author Eddú Meléndez
  * @since 1.5.0
  */
-public interface ClusterCustomizer {
+public interface ClusterBuilderCustomizer {
 
 	/**
-	 * Customize the {@link Cluster}.
-	 * @param cluster the cluster to customize
+	 * Customize the {@link Cluster.Builder}.
+	 * @param clusterBuilder the builder to customize
 	 */
-	void customize(Cluster cluster);
+	void customize(Cluster.Builder clusterBuilder);
 
 }

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/cassandra/CassandraAutoConfigurationTests.java

@@ -64,12 +64,21 @@ public class CassandraAutoConfigurationTests {
 
 	@Test
 	public void createCustomizeCluster() {
-		load(ClusterConfig.class);
+		load(MockCustomizerConfig.class);
 		assertThat(this.context.getBeanNamesForType(Cluster.class).length).isEqualTo(1);
-		assertThat(this.context.getBeanNamesForType(ClusterCustomizer.class).length)
+		assertThat(this.context.getBeanNamesForType(ClusterBuilderCustomizer.class).length)
 				.isEqualTo(1);
 	}
 
+	@Test
+	public void customizerOverridesAutoConfig() {
+		load(SimpleCustomizerConfig.class,
+				"spring.data.cassandra.cluster-name=testcluster");
+		assertThat(this.context.getBeanNamesForType(Cluster.class).length).isEqualTo(1);
+		Cluster cluster = this.context.getBean(Cluster.class);
+		assertThat(cluster.getClusterName()).isEqualTo("overridden-name");
+	}
+
 	private void load(String... environment) {
 		load(null, environment);
 	}
@@ -87,11 +96,26 @@ public class CassandraAutoConfigurationTests {
 	}
 
 	@Configuration
-	static class ClusterConfig {
+	static class MockCustomizerConfig {
+
+		@Bean
+		public ClusterBuilderCustomizer customizer() {
+			return mock(ClusterBuilderCustomizer.class);
+		}
+
+	}
+
+	@Configuration
+	static class SimpleCustomizerConfig {
 
 		@Bean
-		public ClusterCustomizer customizer() {
-			return mock(ClusterCustomizer.class);
+		public ClusterBuilderCustomizer customizer() {
+			return new ClusterBuilderCustomizer() {
+				@Override
+				public void customize(Cluster.Builder clusterBuilder) {
+					clusterBuilder.withClusterName("overridden-name");
+				}
+			};
 		}
 
 	}