Polishing.

Original pull request: #605
See #3148
See #2939

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/TransientClientSessionException.java

@@ -16,24 +16,23 @@
 package org.springframework.data.mongodb;
 
 import org.springframework.dao.TransientDataAccessException;
-import org.springframework.lang.Nullable;
 
 /**
  * {@link TransientDataAccessException} specific to MongoDB {@link com.mongodb.session.ClientSession} related data
  * access failures such as reading data using an already closed session.
  *
  * @author Christoph Strobl
- * @since 3.3
+ * @since 4.4
  */
 public class TransientClientSessionException extends TransientMongoDbException {
 
 	/**
 	 * Constructor for {@link TransientClientSessionException}.
 	 *
-	 * @param msg the detail message. Can be {@literal null}.
-	 * @param cause the root cause. Can be {@literal null}.
+	 * @param msg the detail message.
+	 * @param cause the root cause.
 	 */
-	public TransientClientSessionException(@Nullable String msg, @Nullable Throwable cause) {
+	public TransientClientSessionException(String msg, Throwable cause) {
 		super(msg, cause);
 	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/TransientMongoDbException.java

@@ -16,25 +16,24 @@
 package org.springframework.data.mongodb;
 
 import org.springframework.dao.TransientDataAccessException;
-import org.springframework.lang.Nullable;
 
 /**
  * Root of the hierarchy of MongoDB specific data access exceptions that are considered transient such as
  * {@link com.mongodb.MongoException MongoExceptions} carrying {@link com.mongodb.MongoException#hasErrorLabel(String)
  * specific labels}.
  *
  * @author Christoph Strobl
- * @since 3.3
+ * @since 4.4
  */
 public class TransientMongoDbException extends TransientDataAccessException {
 
 	/**
 	 * Constructor for {@link TransientMongoDbException}.
 	 *
-	 * @param msg the detail message. Can be {@literal null}.
-	 * @param cause the root cause. Can be {@literal null}.
+	 * @param msg the detail message.
+	 * @param cause the root cause.
 	 */
-	public TransientMongoDbException(String msg, @Nullable Throwable cause) {
+	public TransientMongoDbException(String msg, Throwable cause) {
 		super(msg, cause);
 	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoClientFactoryBean.java

@@ -55,16 +55,14 @@
  */
 public class MongoClientFactoryBean extends AbstractFactoryBean<MongoClient> implements PersistenceExceptionTranslator {
 
-	private static final PersistenceExceptionTranslator DEFAULT_EXCEPTION_TRANSLATOR = new MongoExceptionTranslator();
-
 	private @Nullable MongoClientSettings mongoClientSettings;
 	private @Nullable String host;
 	private @Nullable Integer port;
 	private @Nullable List<MongoCredential> credential = null;
 	private @Nullable ConnectionString connectionString;
 	private @Nullable String replicaSet = null;
 
-	private PersistenceExceptionTranslator exceptionTranslator = DEFAULT_EXCEPTION_TRANSLATOR;
+	private PersistenceExceptionTranslator exceptionTranslator = MongoExceptionTranslator.DEFAULT_EXCEPTION_TRANSLATOR;
 
 	/**
 	 * Set the {@link MongoClientSettings} to be used when creating {@link MongoClient}.
@@ -116,23 +114,34 @@ public void setReplicaSet(@Nullable String replicaSet) {
 	 * @param exceptionTranslator
 	 */
 	public void setExceptionTranslator(@Nullable PersistenceExceptionTranslator exceptionTranslator) {
-		this.exceptionTranslator = exceptionTranslator == null ? DEFAULT_EXCEPTION_TRANSLATOR : exceptionTranslator;
-	}
-
-	public Class<? extends MongoClient> getObjectType() {
-		return MongoClient.class;
+		this.exceptionTranslator = exceptionTranslator == null ? MongoExceptionTranslator.DEFAULT_EXCEPTION_TRANSLATOR
+				: exceptionTranslator;
 	}
 
+	@Override
 	@Nullable
 	public DataAccessException translateExceptionIfPossible(RuntimeException ex) {
 		return exceptionTranslator.translateExceptionIfPossible(ex);
 	}
 
+	@Override
+	public Class<? extends MongoClient> getObjectType() {
+		return MongoClient.class;
+	}
+
 	@Override
 	protected MongoClient createInstance() throws Exception {
 		return createMongoClient(computeClientSetting());
 	}
 
+	@Override
+	protected void destroyInstance(@Nullable MongoClient instance) throws Exception {
+
+		if (instance != null) {
+			instance.close();
+		}
+	}
+
 	/**
 	 * Create {@link MongoClientSettings} based on configuration and priority (lower is better).
 	 * <ol>
@@ -324,14 +333,6 @@ private <T> T computeSettingsValue(T defaultValue, T fromSettings, T fromConnect
 		return !fromConnectionStringIsDefault ? fromConnectionString : defaultValue;
 	}
 
-	@Override
-	protected void destroyInstance(@Nullable MongoClient instance) throws Exception {
-
-		if (instance != null) {
-			instance.close();
-		}
-	}
-
 	private MongoClient createMongoClient(MongoClientSettings settings) throws UnknownHostException {
 		return MongoClients.create(settings, SpringDataMongoDB.driverInformation());
 	}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoDatabaseFactorySupport.java

@@ -32,8 +32,7 @@
 
 /**
  * Common base class for usage with both {@link com.mongodb.client.MongoClients} defining common properties such as
- * database name and exception translator.
- * <br />
+ * database name and exception translator. <br />
  * Not intended to be used directly.
  *
  * @author Christoph Strobl
@@ -47,8 +46,8 @@ public abstract class MongoDatabaseFactorySupport<C> implements MongoDatabaseFac
 	private final C mongoClient;
 	private final String databaseName;
 	private final boolean mongoInstanceCreated;
-	private final PersistenceExceptionTranslator exceptionTranslator;
 
+	private PersistenceExceptionTranslator exceptionTranslator;
 	private @Nullable WriteConcern writeConcern;
 
 	/**
@@ -75,15 +74,31 @@ protected MongoDatabaseFactorySupport(C mongoClient, String databaseName, boolea
 		this.exceptionTranslator = exceptionTranslator;
 	}
 
+	/**
+	 * Configures the {@link PersistenceExceptionTranslator} to be used.
+	 *
+	 * @param exceptionTranslator the exception translator to set.
+	 * @since 4.4
+	 */
+	public void setExceptionTranslator(PersistenceExceptionTranslator exceptionTranslator) {
+		this.exceptionTranslator = exceptionTranslator;
+	}
+
+	@Override
+	public PersistenceExceptionTranslator getExceptionTranslator() {
+		return this.exceptionTranslator;
+	}
+
 	/**
 	 * Configures the {@link WriteConcern} to be used on the {@link MongoDatabase} instance being created.
 	 *
-	 * @param writeConcern the writeConcern to set
+	 * @param writeConcern the writeConcern to set.
 	 */
 	public void setWriteConcern(WriteConcern writeConcern) {
 		this.writeConcern = writeConcern;
 	}
 
+	@Override
 	public MongoDatabase getMongoDatabase() throws DataAccessException {
 		return getMongoDatabase(getDefaultDatabaseName());
 	}
@@ -116,10 +131,7 @@ public void destroy() throws Exception {
 		}
 	}
 
-	public PersistenceExceptionTranslator getExceptionTranslator() {
-		return this.exceptionTranslator;
-	}
-
+	@Override
 	public MongoDatabaseFactory withSession(ClientSession session) {
 		return new MongoDatabaseFactorySupport.ClientSessionBoundMongoDbFactory(session, this);
 	}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoExceptionTranslator.java

@@ -18,18 +18,17 @@
 import java.util.Set;
 
 import org.bson.BsonInvalidOperationException;
+
 import org.springframework.dao.DataAccessException;
 import org.springframework.dao.DataAccessResourceFailureException;
 import org.springframework.dao.DataIntegrityViolationException;
 import org.springframework.dao.DuplicateKeyException;
 import org.springframework.dao.InvalidDataAccessApiUsageException;
 import org.springframework.dao.InvalidDataAccessResourceUsageException;
 import org.springframework.dao.PermissionDeniedDataAccessException;
-import org.springframework.dao.TransientDataAccessException;
 import org.springframework.dao.support.PersistenceExceptionTranslator;
 import org.springframework.data.mongodb.ClientSessionException;
 import org.springframework.data.mongodb.TransientClientSessionException;
-import org.springframework.data.mongodb.TransientMongoDbException;
 import org.springframework.data.mongodb.UncategorizedMongoDbException;
 import org.springframework.data.mongodb.util.MongoDbErrorCodes;
 import org.springframework.lang.Nullable;
@@ -53,6 +52,8 @@
  */
 public class MongoExceptionTranslator implements PersistenceExceptionTranslator {
 
+	public static final MongoExceptionTranslator DEFAULT_EXCEPTION_TRANSLATOR = new MongoExceptionTranslator();
+
 	private static final Set<String> DUPLICATE_KEY_EXCEPTIONS = Set.of("MongoException.DuplicateKey",
 			"DuplicateKeyException");
 
@@ -70,18 +71,7 @@ public class MongoExceptionTranslator implements PersistenceExceptionTranslator
 	@Override
 	@Nullable
 	public DataAccessException translateExceptionIfPossible(RuntimeException ex) {
-
-		DataAccessException translatedException = doTranslateException(ex);
-		if (translatedException == null) {
-			return null;
-		}
-
-		// Translated exceptions that per se are not be recoverable (eg. WriteConflicts), might still be transient inside a
-		// transaction. Let's wrap those.
-		return (isTransientFailure(ex) && !(translatedException instanceof TransientDataAccessException))
-				? new TransientMongoDbException(ex.getMessage(), translatedException)
-				: translatedException;
-
+		return doTranslateException(ex);
 	}
 
 	@Nullable
@@ -180,21 +170,23 @@ DataAccessException doTranslateException(RuntimeException ex) {
 	/**
 	 * Check if a given exception holds an error label indicating a transient failure.
 	 *
-	 * @param e
+	 * @param e the exception to inspect.
 	 * @return {@literal true} if the given {@link Exception} is a {@link MongoException} holding one of the transient
 	 *         exception error labels.
 	 * @see MongoException#hasErrorLabel(String)
-	 * @since 3.3
+	 * @since 4.4
 	 */
-	public static boolean isTransientFailure(Exception e) {
+	public boolean isTransientFailure(Exception e) {
 
-		if (!(e instanceof MongoException)) {
-			return false;
+		if (e instanceof MongoException mongoException) {
+			return mongoException.hasErrorLabel(MongoException.TRANSIENT_TRANSACTION_ERROR_LABEL)
+					|| mongoException.hasErrorLabel(MongoException.UNKNOWN_TRANSACTION_COMMIT_RESULT_LABEL);
 		}
 
-		MongoException mongoException = (MongoException) e;
+		if (e.getCause() != e && e.getCause() instanceof Exception ex) {
+			return isTransientFailure(ex);
+		}
 
-		return mongoException.hasErrorLabel(MongoException.TRANSIENT_TRANSACTION_ERROR_LABEL)
-				|| mongoException.hasErrorLabel(MongoException.UNKNOWN_TRANSACTION_COMMIT_RESULT_LABEL);
+		return false;
 	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveMongoClientFactoryBean.java

@@ -36,13 +36,11 @@
 public class ReactiveMongoClientFactoryBean extends AbstractFactoryBean<MongoClient>
 		implements PersistenceExceptionTranslator {
 
-	private static final PersistenceExceptionTranslator DEFAULT_EXCEPTION_TRANSLATOR = new MongoExceptionTranslator();
-
 	private @Nullable String connectionString;
 	private @Nullable String host;
 	private @Nullable Integer port;
 	private @Nullable MongoClientSettings mongoClientSettings;
-	private PersistenceExceptionTranslator exceptionTranslator = DEFAULT_EXCEPTION_TRANSLATOR;
+	private PersistenceExceptionTranslator exceptionTranslator = MongoExceptionTranslator.DEFAULT_EXCEPTION_TRANSLATOR;
 
 	/**
 	 * Configures the host to connect to.
@@ -86,7 +84,13 @@ public void setMongoClientSettings(@Nullable MongoClientSettings mongoClientSett
 	 * @param exceptionTranslator
 	 */
 	public void setExceptionTranslator(@Nullable PersistenceExceptionTranslator exceptionTranslator) {
-		this.exceptionTranslator = exceptionTranslator == null ? DEFAULT_EXCEPTION_TRANSLATOR : exceptionTranslator;
+		this.exceptionTranslator = exceptionTranslator == null ? MongoExceptionTranslator.DEFAULT_EXCEPTION_TRANSLATOR
+				: exceptionTranslator;
+	}
+
+	@Override
+	public DataAccessException translateExceptionIfPossible(RuntimeException ex) {
+		return exceptionTranslator.translateExceptionIfPossible(ex);
 	}
 
 	@Override
@@ -123,8 +127,4 @@ protected void destroyInstance(@Nullable MongoClient instance) throws Exception
 		instance.close();
 	}
 
-	@Override
-	public DataAccessException translateExceptionIfPossible(RuntimeException ex) {
-		return exceptionTranslator.translateExceptionIfPossible(ex);
-	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/SimpleMongoClientDatabaseFactory.java

@@ -72,7 +72,7 @@ public SimpleMongoClientDatabaseFactory(MongoClient mongoClient, String database
 	 * @param mongoInstanceCreated
 	 */
 	SimpleMongoClientDatabaseFactory(MongoClient mongoClient, String databaseName, boolean mongoInstanceCreated) {
-		super(mongoClient, databaseName, mongoInstanceCreated, new MongoExceptionTranslator());
+		super(mongoClient, databaseName, mongoInstanceCreated, MongoExceptionTranslator.DEFAULT_EXCEPTION_TRANSLATOR);
 	}
 
 	@Override

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/SimpleReactiveMongoDatabaseFactory.java

@@ -51,8 +51,7 @@ public class SimpleReactiveMongoDatabaseFactory implements DisposableBean, React
 	private final String databaseName;
 	private final boolean mongoInstanceCreated;
 
-	private final PersistenceExceptionTranslator exceptionTranslator;
-
+	private PersistenceExceptionTranslator exceptionTranslator = MongoExceptionTranslator.DEFAULT_EXCEPTION_TRANSLATOR;
 	private @Nullable WriteConcern writeConcern;
 
 	/**
@@ -85,7 +84,21 @@ private SimpleReactiveMongoDatabaseFactory(MongoClient client, String databaseNa
 		this.mongo = client;
 		this.databaseName = databaseName;
 		this.mongoInstanceCreated = mongoInstanceCreated;
-		this.exceptionTranslator = new MongoExceptionTranslator();
+	}
+
+	/**
+	 * Configures the {@link PersistenceExceptionTranslator} to be used.
+	 *
+	 * @param exceptionTranslator the exception translator to set.
+	 * @since 4.4
+	 */
+	public void setExceptionTranslator(PersistenceExceptionTranslator exceptionTranslator) {
+		this.exceptionTranslator = exceptionTranslator;
+	}
+
+	@Override
+	public PersistenceExceptionTranslator getExceptionTranslator() {
+		return this.exceptionTranslator;
 	}
 
 	/**
@@ -97,10 +110,12 @@ public void setWriteConcern(WriteConcern writeConcern) {
 		this.writeConcern = writeConcern;
 	}
 
+	@Override
 	public Mono<MongoDatabase> getMongoDatabase() throws DataAccessException {
 		return getMongoDatabase(databaseName);
 	}
 
+	@Override
 	public Mono<MongoDatabase> getMongoDatabase(String dbName) throws DataAccessException {
 
 		Assert.hasText(dbName, "Database name must not be empty");
@@ -118,17 +133,14 @@ public Mono<MongoDatabase> getMongoDatabase(String dbName) throws DataAccessExce
 	 *
 	 * @see DisposableBean#destroy()
 	 */
+	@Override
 	public void destroy() throws Exception {
 
 		if (mongoInstanceCreated) {
 			mongo.close();
 		}
 	}
 
-	public PersistenceExceptionTranslator getExceptionTranslator() {
-		return this.exceptionTranslator;
-	}
-
 	@Override
 	public CodecRegistry getCodecRegistry() {
 		return this.mongo.getDatabase(databaseName).getCodecRegistry();