DATAMONGO-1919 - Polishing.

Remove unused imports, deprecated MongoClientVersion methods for drivers no longer supported and remove their usage throughout the codebase and partially revert changes in MongoSimpleTypes because all org.bson types have been included in the 3.8 release of org.mongodb.bson.

Original Pull Request: spring-projects#572

Author: christophstrobl

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/AbstractReactiveMongoConfiguration.java

@@ -81,8 +81,7 @@ public ReactiveMongoDatabaseFactory reactiveMongoDbFactory() {
 	@Bean
 	public MappingMongoConverter mappingMongoConverter() throws Exception {
 
-		MappingMongoConverter converter = new MappingMongoConverter(NoOpDbRefResolver.INSTANCE,
-				mongoMappingContext());
+		MappingMongoConverter converter = new MappingMongoConverter(NoOpDbRefResolver.INSTANCE, mongoMappingContext());
 		converter.setCustomConversions(customConversions());
 
 		return converter;

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

@@ -1221,8 +1221,7 @@ protected WriteConcern prepareWriteConcern(MongoAction mongoAction) {
 	@Nullable
 	private WriteConcern potentiallyForceAcknowledgedWrite(@Nullable WriteConcern wc) {
 
-		if (ObjectUtils.nullSafeEquals(WriteResultChecking.EXCEPTION, writeResultChecking)
-				&& MongoClientVersion.isMongo3Driver()) {
+		if (ObjectUtils.nullSafeEquals(WriteResultChecking.EXCEPTION, writeResultChecking)) {
 			if (wc == null || wc.getWObject() == null
 					|| (wc.getWObject() instanceof Number && ((Number) wc.getWObject()).intValue() < 1)) {
 				return WriteConcern.ACKNOWLEDGED;

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

@@ -2626,8 +2626,7 @@ protected WriteConcern prepareWriteConcern(MongoAction mongoAction) {
 	@Nullable
 	private WriteConcern potentiallyForceAcknowledgedWrite(@Nullable WriteConcern wc) {
 
-		if (ObjectUtils.nullSafeEquals(WriteResultChecking.EXCEPTION, writeResultChecking)
-				&& MongoClientVersion.isMongo3Driver()) {
+		if (ObjectUtils.nullSafeEquals(WriteResultChecking.EXCEPTION, writeResultChecking)) {
 			if (wc == null || wc.getWObject() == null
 					|| (wc.getWObject() instanceof Number && ((Number) wc.getWObject()).intValue() < 1)) {
 				return WriteConcern.ACKNOWLEDGED;

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

@@ -43,7 +43,6 @@
 import org.springframework.data.mongodb.ClientSessionException;
 import org.springframework.data.mongodb.LazyLoadingException;
 import org.springframework.data.mongodb.MongoDbFactory;
-import org.springframework.data.mongodb.core.mapping.MongoPersistentEntity;
 import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
 import org.springframework.lang.Nullable;
 import org.springframework.objenesis.ObjenesisStd;

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

@@ -17,13 +17,9 @@
 
 import java.util.List;
 
-import javax.annotation.Nonnull;
-
 import org.bson.Document;
-import org.springframework.data.mongodb.core.mapping.MongoPersistentEntity;
 import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
 import org.springframework.lang.Nullable;
-import org.springframework.util.StringUtils;
 
 import com.mongodb.DBRef;
 
@@ -32,6 +28,7 @@
  * {@link UnsupportedOperationException} when attempting to resolve database references.
  *
  * @author Mark Paluch
+ * @author Christoph Strobl
  * @since 2.1
  */
 public enum NoOpDbRefResolver implements DbRefResolver {
@@ -40,22 +37,24 @@ public enum NoOpDbRefResolver implements DbRefResolver {
 
 	/*
 	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.convert.DbRefResolver#resolveDbRef(org.springframework.data.mongodb.core.mapping.MongoPersistentProperty, org.springframework.data.mongodb.core.convert.DbRefResolverCallback)
+	 * @see org.springframework.data.mongodb.core.convert.DbRefResolver#resolveDbRef(org.springframework.data.mongodb.core.mapping.MongoPersistentProperty, org.springframework.data.mongodb.core.convert.DbRefResolverCallback, org.springframework.data.mongodb.core.convert.DbRefProxyHandler)
 	 */
 	@Override
 	@Nullable
-	public Object resolveDbRef(@Nonnull MongoPersistentProperty property, @Nonnull DBRef dbref,
-			@Nonnull DbRefResolverCallback callback, @Nonnull DbRefProxyHandler proxyHandler) {
-		throw new UnsupportedOperationException("DBRef resolution not supported!");
+	public Object resolveDbRef(MongoPersistentProperty property, @Nullable DBRef dbref, DbRefResolverCallback callback,
+			DbRefProxyHandler proxyHandler) {
+
+		return handle();
 	}
 
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mongodb.core.convert.DbRefResolver#fetch(com.mongodb.DBRef)
 	 */
 	@Override
+	@Nullable
 	public Document fetch(DBRef dbRef) {
-		throw new UnsupportedOperationException("DBRef resolution not supported!");
+		return handle();
 	}
 
 	/*
@@ -64,6 +63,10 @@ public Document fetch(DBRef dbRef) {
 	 */
 	@Override
 	public List<Document> bulkFetch(List<DBRef> dbRefs) {
-		throw new UnsupportedOperationException("DBRef resolution not supported!");
+		return handle();
+	}
+
+	private <T> T handle() throws UnsupportedOperationException {
+		throw new UnsupportedOperationException("DBRef resolution is not supported!");
 	}
 }

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

@@ -24,6 +24,9 @@
 
 import org.bson.BsonObjectId;
 import org.bson.types.Binary;
+import org.bson.types.CodeWScope;
+import org.bson.types.CodeWithScope;
+import org.bson.types.Decimal128;
 import org.bson.types.ObjectId;
 import org.springframework.data.mapping.model.SimpleTypeHolder;
 import org.springframework.data.mongodb.util.MongoClientVersion;
@@ -36,49 +39,34 @@
  *
  * @author Oliver Gierke
  * @author Christoph Strobl
- * @author Mark Paluch
  */
 public abstract class MongoSimpleTypes {
 
 	public static final Set<Class<?>> AUTOGENERATED_ID_TYPES;
 
 	static {
-		Set<Class<?>> classes = new HashSet<>();
+		Set<Class<?>> classes = new HashSet<Class<?>>();
 		classes.add(ObjectId.class);
 		classes.add(String.class);
 		classes.add(BigInteger.class);
 		AUTOGENERATED_ID_TYPES = Collections.unmodifiableSet(classes);
 
-		Set<Class<?>> simpleTypes = new HashSet<>();
+		Set<Class<?>> simpleTypes = new HashSet<Class<?>>();
 		simpleTypes.add(DBRef.class);
 		simpleTypes.add(ObjectId.class);
 		simpleTypes.add(BsonObjectId.class);
+		simpleTypes.add(CodeWScope.class);
+		simpleTypes.add(CodeWithScope.class);
 		simpleTypes.add(org.bson.Document.class);
 		simpleTypes.add(Pattern.class);
 		simpleTypes.add(Binary.class);
 		simpleTypes.add(UUID.class);
-
-		if (ClassUtils.isPresent("org.bson.types.CodeWScope", MongoSimpleTypes.class.getClassLoader())) {
-			simpleTypes.add(resolveClassName("org.bson.types.CodeWScope"));
-		}
-
-		if (ClassUtils.isPresent("org.bson.types.CodeWithScope", MongoSimpleTypes.class.getClassLoader())) {
-			simpleTypes.add(resolveClassName("org.bson.types.CodeWithScope"));
-		}
-
-		if (MongoClientVersion.isMongo34Driver()) {
-			simpleTypes.add(resolveClassName("org.bson.types.Decimal128"));
-		}
-
+		simpleTypes.add(Decimal128.class);
 		MONGO_SIMPLE_TYPES = Collections.unmodifiableSet(simpleTypes);
 	}
 
 	private static final Set<Class<?>> MONGO_SIMPLE_TYPES;
 	public static final SimpleTypeHolder HOLDER = new SimpleTypeHolder(MONGO_SIMPLE_TYPES, true);
 
 	private MongoSimpleTypes() {}
-
-	private static Class<?> resolveClassName(String className) {
-		return ClassUtils.resolveClassName(className, MongoSimpleTypes.class.getClassLoader());
-	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/util/MongoClientVersion.java

@@ -26,34 +26,54 @@
  */
 public class MongoClientVersion {
 
-	private static final boolean IS_MONGO_30 = ClassUtils.isPresent("com.mongodb.binding.SingleServerBinding",
+	private static final boolean SYNC_CLIENT_PRESENT = ClassUtils.isPresent("com.mongodb.MongoClient",
 			MongoClientVersion.class.getClassLoader());
 
-	private static final boolean IS_MONGO_34 = ClassUtils.isPresent("org.bson.types.Decimal128",
+	private static final boolean ASYNC_CLIENT_PRESENT = ClassUtils.isPresent("com.mongodb.async.client.MongoClient",
 			MongoClientVersion.class.getClassLoader());
 
-	private static final boolean IS_ASYNC_CLIENT = ClassUtils.isPresent("com.mongodb.async.client.MongoClient",
-			MongoClientVersion.class.getClassLoader());
+	private static final boolean REACTIVE_CLIENT_PRESENT = ClassUtils
+			.isPresent("com.mongodb.reactivestreams.client.MongoClient", MongoClientVersion.class.getClassLoader());
 
 	/**
 	 * @return {@literal true} if MongoDB Java driver version 3.0 or later is on classpath.
+	 * @deprecated since 2.1, which requires MongoDB Java driver 3.8. Returns {@literal true} by default.
 	 */
+	@Deprecated
 	public static boolean isMongo3Driver() {
-		return IS_MONGO_30;
+		return true;
 	}
 
 	/**
 	 * @return {@literal true} if MongoDB Java driver version 3.4 or later is on classpath.
 	 * @since 1.10
+	 * @deprecated since 2.1, which requires MongoDB Java driver 3.8. Returns {@literal true} by default.
 	 */
+	@Deprecated
 	public static boolean isMongo34Driver() {
-		return IS_MONGO_34;
+		return true;
 	}
 
 	/**
-	 * @return {@literal true} if MongoDB Java driver is on classpath.
+	 * @return {@literal true} if the async MongoDB Java driver is on classpath.
 	 */
 	public static boolean isAsyncClient() {
-		return IS_ASYNC_CLIENT;
+		return ASYNC_CLIENT_PRESENT;
+	}
+
+	/**
+	 * @return {@literal true} if the sync MongoDB Java driver is on classpath.
+	 * @since 2.1
+	 */
+	public static boolean isSyncClientPresent() {
+		return SYNC_CLIENT_PRESENT;
+	}
+
+	/**
+	 * @return {@literal true} if the reactive MongoDB Java driver is on classpath.
+	 * @since 2.1
+	 */
+	public static boolean isReactiveClientPresent() {
+		return REACTIVE_CLIENT_PRESENT;
 	}
 }

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/MongoOptionsFactoryBeanUnitTests.java

@@ -3420,8 +3420,6 @@ public void findsByGenericNestedListElements() {
 	public void decimal128TypeShouldBeSavedAndLoadedCorrectly()
 			throws NoSuchMethodException, IllegalAccessException, InvocationTargetException, InstantiationException {
 
-		assumeThat(MongoClientVersion.isMongo34Driver(), is(true));
-
 		Class<?> decimal128Type = ClassUtils.resolveClassName("org.bson.types.Decimal128", null);
 
 		WithObjectTypeProperty source = new WithObjectTypeProperty();

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/MongoTemplateTests.java

@@ -111,18 +111,14 @@ public void convertDocumentWithMapDBRef() {
 		when(dbRef.getId()).thenReturn(BigInteger.ONE);
 		when(dbRef.getCollectionName()).thenReturn("collection-1");
 
-		if (MongoClientVersion.isMongo3Driver()) {
-			MongoDatabase dbMock = mock(MongoDatabase.class);
-			MongoCollection collectionMock = mock(MongoCollection.class);
-			when(dbFactory.getDb()).thenReturn(dbMock);
-			when(dbMock.getCollection(anyString(), eq(Document.class))).thenReturn(collectionMock);
-
-			FindIterable fi = mock(FindIterable.class);
-			when(fi.first()).thenReturn(mapValDocument);
-			when(collectionMock.find(Mockito.any(Bson.class))).thenReturn(fi);
-		} else {
-			when(dbRefResolver.fetch(dbRef)).thenReturn(mapValDocument);
-		}
+		MongoDatabase dbMock = mock(MongoDatabase.class);
+		MongoCollection collectionMock = mock(MongoCollection.class);
+		when(dbFactory.getDb()).thenReturn(dbMock);
+		when(dbMock.getCollection(anyString(), eq(Document.class))).thenReturn(collectionMock);
+
+		FindIterable fi = mock(FindIterable.class);
+		when(fi.first()).thenReturn(mapValDocument);
+		when(collectionMock.find(Mockito.any(Bson.class))).thenReturn(fi);
 
 		MapDBRef mapDBRef = new MapDBRef();