Polishing.

Tweak naming. Add Javadoc and documentation.

See #1628
Original pull request: #4552

Author: mp911de

Diff for: spring-data-mongodb/src/main/java/org/springframework/data/mongodb/DefaultMongoTransactionOptionsResolver.java

@@ -18,7 +18,6 @@
 import java.util.Map;
 import java.util.Set;
 
-import org.springframework.data.util.Lazy;
 import org.springframework.lang.Nullable;
 
 /**
@@ -30,14 +29,12 @@
  * @author Christoph Strobl
  * @since 4.3
  */
-class DefaultMongoTransactionOptionsResolver implements MongoTransactionOptionsResolver {
+enum DefaultMongoTransactionOptionsResolver implements MongoTransactionOptionsResolver {
 
-	static final Lazy<MongoTransactionOptionsResolver> INSTANCE = Lazy.of(DefaultMongoTransactionOptionsResolver::new);
+	INSTANCE;
 
 	private static final String PREFIX = "mongo:";
 
-	private DefaultMongoTransactionOptionsResolver() {}
-
 	@Override
 	public MongoTransactionOptions convert(Map<String, String> options) {
 
@@ -53,7 +50,7 @@ public String getLabelPrefix() {
 
 	private static void validateKeys(Set<String> keys) {
 
-		if (!keys.stream().allMatch(SimpleMongoTransactionOptions.KNOWN_KEYS::contains)) {
+		if (!SimpleMongoTransactionOptions.KNOWN_KEYS.containsAll(keys)) {
 
 			throw new IllegalArgumentException("Transaction labels contained invalid values. Has to be one of %s"
 					.formatted(SimpleMongoTransactionOptions.KNOWN_KEYS));

Diff for: spring-data-mongodb/src/main/java/org/springframework/data/mongodb/MongoTransactionManager.java

@@ -64,59 +64,61 @@
 public class MongoTransactionManager extends AbstractPlatformTransactionManager
 		implements ResourceTransactionManager, InitializingBean {
 
-	private @Nullable MongoDatabaseFactory dbFactory;
+	private @Nullable MongoDatabaseFactory databaseFactory;
 	private MongoTransactionOptions options;
-	private MongoTransactionOptionsResolver transactionOptionsResolver;
+	private final MongoTransactionOptionsResolver transactionOptionsResolver;
 
 	/**
-	 * Create a new {@link MongoTransactionManager} for bean-style usage.
-	 * <br />
+	 * Create a new {@link MongoTransactionManager} for bean-style usage. <br />
 	 * <strong>Note:</strong>The {@link MongoDatabaseFactory db factory} has to be
-	 * {@link #setDbFactory(MongoDatabaseFactory) set} before using the instance. Use this constructor to prepare a
-	 * {@link MongoTransactionManager} via a {@link org.springframework.beans.factory.BeanFactory}.
-	 * <br />
+	 * {@link #setDatabaseFactory(MongoDatabaseFactory) set} before using the instance. Use this constructor to prepare a
+	 * {@link MongoTransactionManager} via a {@link org.springframework.beans.factory.BeanFactory}. <br />
 	 * Optionally it is possible to set default {@link TransactionOptions transaction options} defining
 	 * {@link com.mongodb.ReadConcern} and {@link com.mongodb.WriteConcern}.
 	 *
-	 * @see #setDbFactory(MongoDatabaseFactory)
+	 * @see #setDatabaseFactory(MongoDatabaseFactory)
 	 * @see #setTransactionSynchronization(int)
 	 */
-	public MongoTransactionManager() {}
+	public MongoTransactionManager() {
+		this.transactionOptionsResolver = MongoTransactionOptionsResolver.defaultResolver();
+	}
 
 	/**
 	 * Create a new {@link MongoTransactionManager} obtaining sessions from the given {@link MongoDatabaseFactory}.
 	 *
-	 * @param dbFactory must not be {@literal null}.
+	 * @param databaseFactory must not be {@literal null}.
 	 */
-	public MongoTransactionManager(MongoDatabaseFactory dbFactory) {
-		this(dbFactory, null);
+	public MongoTransactionManager(MongoDatabaseFactory databaseFactory) {
+		this(databaseFactory, null);
 	}
 
 	/**
 	 * Create a new {@link MongoTransactionManager} obtaining sessions from the given {@link MongoDatabaseFactory}
 	 * applying the given {@link TransactionOptions options}, if present, when starting a new transaction.
 	 *
-	 * @param dbFactory must not be {@literal null}.
+	 * @param databaseFactory must not be {@literal null}.
 	 * @param options can be {@literal null}.
 	 */
-	public MongoTransactionManager(MongoDatabaseFactory dbFactory, @Nullable TransactionOptions options) {
-		this(dbFactory, MongoTransactionOptionsResolver.defaultResolver(), MongoTransactionOptions.of(options));
+	public MongoTransactionManager(MongoDatabaseFactory databaseFactory, @Nullable TransactionOptions options) {
+		this(databaseFactory, MongoTransactionOptionsResolver.defaultResolver(), MongoTransactionOptions.of(options));
 	}
 
 	/**
 	 * Create a new {@link MongoTransactionManager} obtaining sessions from the given {@link MongoDatabaseFactory}
 	 * applying the given {@link TransactionOptions options}, if present, when starting a new transaction.
 	 *
-	 * @param dbFactory must not be {@literal null}.
-	 * @param transactionOptionsResolver
+	 * @param databaseFactory must not be {@literal null}.
+	 * @param transactionOptionsResolver must not be {@literal null}.
 	 * @param defaultTransactionOptions can be {@literal null}.
 	 * @since 4.3
 	 */
-	public MongoTransactionManager(MongoDatabaseFactory dbFactory, MongoTransactionOptionsResolver transactionOptionsResolver, MongoTransactionOptions defaultTransactionOptions) {
+	public MongoTransactionManager(MongoDatabaseFactory databaseFactory,
+			MongoTransactionOptionsResolver transactionOptionsResolver, MongoTransactionOptions defaultTransactionOptions) {
 
-		Assert.notNull(dbFactory, "DbFactory must not be null");
+		Assert.notNull(databaseFactory, "MongoDatabaseFactory must not be null");
+		Assert.notNull(transactionOptionsResolver, "MongoTransactionOptionsResolver must not be null");
 
-		this.dbFactory = dbFactory;
+		this.databaseFactory = databaseFactory;
 		this.transactionOptionsResolver = transactionOptionsResolver;
 		this.options = defaultTransactionOptions;
 	}
@@ -278,12 +280,12 @@ protected void doCleanupAfterCompletion(Object transaction) {
 	/**
 	 * Set the {@link MongoDatabaseFactory} that this instance should manage transactions for.
 	 *
-	 * @param dbFactory must not be {@literal null}.
+	 * @param databaseFactory must not be {@literal null}.
 	 */
-	public void setDbFactory(MongoDatabaseFactory dbFactory) {
+	public void setDatabaseFactory(MongoDatabaseFactory databaseFactory) {
 
-		Assert.notNull(dbFactory, "DbFactory must not be null");
-		this.dbFactory = dbFactory;
+		Assert.notNull(databaseFactory, "DbFactory must not be null");
+		this.databaseFactory = databaseFactory;
 	}
 
 	/**
@@ -301,8 +303,8 @@ public void setOptions(@Nullable TransactionOptions options) {
 	 * @return can be {@literal null}.
 	 */
 	@Nullable
-	public MongoDatabaseFactory getDbFactory() {
-		return dbFactory;
+	public MongoDatabaseFactory getDatabaseFactory() {
+		return databaseFactory;
 	}
 
 	@Override
@@ -326,14 +328,14 @@ private MongoResourceHolder newResourceHolder(TransactionDefinition definition,
 	}
 
 	/**
-	 * @throws IllegalStateException if {@link #dbFactory} is {@literal null}.
+	 * @throws IllegalStateException if {@link #databaseFactory} is {@literal null}.
 	 */
 	private MongoDatabaseFactory getRequiredDbFactory() {
 
-		Assert.state(dbFactory != null,
+		Assert.state(databaseFactory != null,
 				"MongoTransactionManager operates upon a MongoDbFactory; Did you forget to provide one; It's required");
 
-		return dbFactory;
+		return databaseFactory;
 	}
 
 	private static MongoTransactionObject extractMongoTransaction(Object transaction) {

Diff for: spring-data-mongodb/src/main/java/org/springframework/data/mongodb/MongoTransactionOptions.java

@@ -17,13 +17,13 @@
 
 import java.time.Duration;
 import java.util.concurrent.TimeUnit;
+import java.util.function.Function;
 
 import org.springframework.data.mongodb.core.ReadConcernAware;
 import org.springframework.data.mongodb.core.ReadPreferenceAware;
 import org.springframework.data.mongodb.core.WriteConcernAware;
 import org.springframework.lang.Nullable;
 
-import com.mongodb.Function;
 import com.mongodb.ReadConcern;
 import com.mongodb.ReadPreference;
 import com.mongodb.TransactionOptions;
@@ -115,24 +115,23 @@ public WriteConcern getWriteConcern() {
 	}
 
 	/**
-	 * Map the current options using the given mapping {@link Function}.
+	 * Apply the current options using the given mapping {@link Function} and return its result.
 	 *
 	 * @param mappingFunction
-	 * @return instance of T.
-	 * @param <T>
+	 * @return result of the mapping function.
 	 */
-	default <T> T as(Function<MongoTransactionOptions, T> mappingFunction) {
+	default <T> T map(Function<MongoTransactionOptions, T> mappingFunction) {
 		return mappingFunction.apply(this);
 	}
 
 	/**
 	 * @return MongoDB driver native {@link TransactionOptions}.
-	 * @see MongoTransactionOptions#as(Function)
+	 * @see MongoTransactionOptions#map(Function)
 	 */
 	@Nullable
 	default TransactionOptions toDriverOptions() {
 
-		return as(it -> {
+		return map(it -> {
 
 			if (MongoTransactionOptions.NONE.equals(it)) {
 				return null;
@@ -157,7 +156,7 @@ default TransactionOptions toDriverOptions() {
 
 	/**
 	 * Factory method to wrap given MongoDB driver native {@link TransactionOptions} into {@link MongoTransactionOptions}.
-	 * 
+	 *
 	 * @param options
 	 * @return {@link MongoTransactionOptions#NONE} if given object is {@literal null}.
 	 */

Diff for: spring-data-mongodb/src/main/java/org/springframework/data/mongodb/MongoTransactionOptionsResolver.java

@@ -28,7 +28,7 @@
  * A {@link TransactionOptionResolver} reading MongoDB specific {@link MongoTransactionOptions transaction options} from
  * a {@link TransactionDefinition}. Implementations of {@link MongoTransactionOptions} may choose a specific
  * {@link #getLabelPrefix() prefix} for {@link TransactionAttribute#getLabels() transaction attribute labels} to avoid
- * evaluating non store specific ones.
+ * evaluating non-store specific ones.
  * <p>
  * {@link TransactionAttribute#getLabels()} evaluated by default should follow the property style using {@code =} to
  * separate key and value pairs.
@@ -50,11 +50,11 @@ public interface MongoTransactionOptionsResolver extends TransactionOptionResolv
 	/**
 	 * Obtain the default {@link MongoTransactionOptionsResolver} implementation using a {@literal mongo:}
 	 * {@link #getLabelPrefix() prefix}.
-	 * 
+	 *
 	 * @return instance of default {@link MongoTransactionOptionsResolver} implementation.
 	 */
 	static MongoTransactionOptionsResolver defaultResolver() {
-		return DefaultMongoTransactionOptionsResolver.INSTANCE.get();
+		return DefaultMongoTransactionOptionsResolver.INSTANCE;
 	}
 
 	/**
@@ -71,16 +71,16 @@ static MongoTransactionOptionsResolver defaultResolver() {
 	 * <p>
 	 * Splits applicable labels property style using {@literal =} as deliminator and removes a potential
 	 * {@link #getLabelPrefix() prefix} before calling {@link #convert(Map)} with filtered label values.
-	 * 
-	 * @param txDefinition
+	 *
+	 * @param definition
 	 * @return {@link MongoTransactionOptions#NONE} in case the given {@link TransactionDefinition} is not a
 	 *         {@link TransactionAttribute} if no matching {@link TransactionAttribute#getLabels() labels} could be found.
 	 * @throws IllegalArgumentException for options that do not map to valid transactions options or malformatted labels.
 	 */
 	@Override
-	default MongoTransactionOptions resolve(TransactionDefinition txDefinition) {
+	default MongoTransactionOptions resolve(TransactionDefinition definition) {
 
-		if (!(txDefinition instanceof TransactionAttribute attribute)) {
+		if (!(definition instanceof TransactionAttribute attribute)) {
 			return MongoTransactionOptions.NONE;
 		}
 

Diff for: spring-data-mongodb/src/main/java/org/springframework/data/mongodb/ReactiveMongoTransactionManager.java

@@ -37,17 +37,14 @@
 /**
  * A {@link org.springframework.transaction.ReactiveTransactionManager} implementation that manages
  * {@link com.mongodb.reactivestreams.client.ClientSession} based transactions for a single
- * {@link org.springframework.data.mongodb.ReactiveMongoDatabaseFactory}.
- * <br />
+ * {@link org.springframework.data.mongodb.ReactiveMongoDatabaseFactory}. <br />
  * Binds a {@link ClientSession} from the specified
  * {@link org.springframework.data.mongodb.ReactiveMongoDatabaseFactory} to the subscriber
- * {@link reactor.util.context.Context}.
- * <br />
+ * {@link reactor.util.context.Context}. <br />
  * {@link org.springframework.transaction.TransactionDefinition#isReadOnly() Readonly} transactions operate on a
  * {@link ClientSession} and enable causal consistency, and also {@link ClientSession#startTransaction() start},
  * {@link com.mongodb.reactivestreams.client.ClientSession#commitTransaction() commit} or
- * {@link ClientSession#abortTransaction() abort} a transaction.
- * <br />
+ * {@link ClientSession#abortTransaction() abort} a transaction. <br />
  * Application code is required to retrieve the {@link com.mongodb.reactivestreams.client.MongoDatabase} via
  * {@link org.springframework.data.mongodb.ReactiveMongoDatabaseUtils#getDatabase(ReactiveMongoDatabaseFactory)} instead
  * of a standard {@link org.springframework.data.mongodb.ReactiveMongoDatabaseFactory#getMongoDatabase()} call. Spring
@@ -68,11 +65,10 @@ public class ReactiveMongoTransactionManager extends AbstractReactiveTransaction
 
 	private @Nullable ReactiveMongoDatabaseFactory databaseFactory;
 	private @Nullable MongoTransactionOptions options;
-	private MongoTransactionOptionsResolver transactionOptionsResolver;
+	private final MongoTransactionOptionsResolver transactionOptionsResolver;
 
 	/**
-	 * Create a new {@link ReactiveMongoTransactionManager} for bean-style usage.
-	 * <br />
+	 * Create a new {@link ReactiveMongoTransactionManager} for bean-style usage. <br />
 	 * <strong>Note:</strong>The {@link org.springframework.data.mongodb.ReactiveMongoDatabaseFactory db factory} has to
 	 * be {@link #setDatabaseFactory(ReactiveMongoDatabaseFactory)} set} before using the instance. Use this constructor
 	 * to prepare a {@link ReactiveMongoTransactionManager} via a {@link org.springframework.beans.factory.BeanFactory}.
@@ -82,7 +78,9 @@ public class ReactiveMongoTransactionManager extends AbstractReactiveTransaction
 	 *
 	 * @see #setDatabaseFactory(ReactiveMongoDatabaseFactory)
 	 */
-	public ReactiveMongoTransactionManager() {}
+	public ReactiveMongoTransactionManager() {
+		this.transactionOptionsResolver = MongoTransactionOptionsResolver.defaultResolver();
+	}
 
 	/**
 	 * Create a new {@link ReactiveMongoTransactionManager} obtaining sessions from the given
@@ -113,14 +111,16 @@ public ReactiveMongoTransactionManager(ReactiveMongoDatabaseFactory databaseFact
 	 * starting a new transaction.
 	 *
 	 * @param databaseFactory must not be {@literal null}.
-	 * @param transactionOptionsResolver
+	 * @param transactionOptionsResolver must not be {@literal null}.
 	 * @param defaultTransactionOptions can be {@literal null}.
-	 *
+	 * @since 4.3
 	 */
-	public ReactiveMongoTransactionManager(ReactiveMongoDatabaseFactory databaseFactory, MongoTransactionOptionsResolver transactionOptionsResolver,
+	public ReactiveMongoTransactionManager(ReactiveMongoDatabaseFactory databaseFactory,
+			MongoTransactionOptionsResolver transactionOptionsResolver,
 			@Nullable MongoTransactionOptions defaultTransactionOptions) {
 
 		Assert.notNull(databaseFactory, "DatabaseFactory must not be null");
+		Assert.notNull(transactionOptionsResolver, "MongoTransactionOptionsResolver must not be null");
 
 		this.databaseFactory = databaseFactory;
 		this.transactionOptionsResolver = transactionOptionsResolver;
@@ -163,7 +163,8 @@ protected Mono<Void> doBegin(TransactionSynchronizationManager synchronizationMa
 
 			}).doOnNext(resourceHolder -> {
 
-				MongoTransactionOptions mongoTransactionOptions = transactionOptionsResolver.resolve(definition).mergeWith(options);
+				MongoTransactionOptions mongoTransactionOptions = transactionOptionsResolver.resolve(definition)
+						.mergeWith(options);
 				mongoTransactionObject.startTransaction(mongoTransactionOptions.toDriverOptions());
 
 				if (logger.isDebugEnabled()) {

Diff for: spring-data-mongodb/src/main/java/org/springframework/data/mongodb/SimpleMongoTransactionOptions.java

@@ -82,6 +82,13 @@ public WriteConcern getWriteConcern() {
 		return writeConcern;
 	}
 
+	@Override
+	public String toString() {
+
+		return "DefaultMongoTransactionOptions{" + "maxCommitTime=" + maxCommitTime + ", readConcern=" + readConcern
+				+ ", readPreference=" + readPreference + ", writeConcern=" + writeConcern + '}';
+	}
+
 	@Nullable
 	private static Duration doGetMaxCommitTime(Map<String, String> options) {
 
@@ -123,13 +130,6 @@ private static <T> T getValue(Map<String, String> options, OptionKey key, Functi
 		return value != null ? convertFunction.apply(value) : null;
 	}
 
-	@Override
-	public String toString() {
-
-		return "DefaultMongoTransactionOptions{" + "maxCommitTime=" + maxCommitTime + ", readConcern=" + readConcern
-				+ ", readPreference=" + readPreference + ", writeConcern=" + writeConcern + '}';
-	}
-
 	enum OptionKey {
 
 		MAX_COMMIT_TIME("maxCommitTime"), READ_CONCERN("readConcern"), READ_PREFERENCE("readPreference"), WRITE_CONCERN(

Diff for: spring-data-mongodb/src/main/java/org/springframework/data/mongodb/TransactionMetadata.java

@@ -20,14 +20,22 @@
 import org.springframework.lang.Nullable;
 
 /**
+ * MongoDB-specific transaction metadata.
+ *
  * @author Christoph Strobl
  * @since 4.3
  */
 public interface TransactionMetadata {
 
+	/**
+	 * @return the maximum commit time. Can be {@literal null} if not configured.
+	 */
 	@Nullable
 	Duration getMaxCommitTime();
 
+	/**
+	 * @return {@literal true} if the max commit time is configured; {@literal false} otherwise.
+	 */
 	default boolean hasMaxCommitTime() {
 		return getMaxCommitTime() != null;
 	}