set of small code-style improvements (spring-attic#2156)

* code-style improvements

Author: s13o

spring-cloud-gcp-data-spanner/src/main/java/org/springframework/cloud/gcp/data/spanner/core/SpannerOperations.java

@@ -66,7 +66,7 @@ public interface SpannerOperations {
 	 *
 	 * @param entityClass the type of the entity
 	 * @param key the key of the object
-	 * @param <T> the type of the object to retrieve.
+	 * @param <T> the type of the object to check.
 	 * @return {@literal true} if an entity with the given key exists, {@literal false} otherwise.
 	 * @throws IllegalArgumentException if {@literal id} is {@literal null}.
 	 */
@@ -160,8 +160,9 @@ <T> List<T> query(Class<T> entityClass, Statement statement,
 	 * Deletes an object based on a key.
 	 * @param entityClass the type of the object to delete.
 	 * @param key the key of the object to delete from storage.
+	 * @param <T> the type of the object to delete.
 	 */
-	void delete(Class entityClass, Key key);
+	<T> void delete(Class<T> entityClass, Key key);
 
 	/**
 	 * Deletes an object from storage.
@@ -173,14 +174,15 @@ <T> List<T> query(Class<T> entityClass, Statement statement,
 	 * Deletes objects from storage in a batch.
 	 * @param objects the objects to delete from storage.
 	 */
-	void deleteAll(Iterable objects);
+	void deleteAll(Iterable<?> objects);
 
 	/**
 	 * Deletes objects given a set of keys.
 	 * @param entityClass the type of object to delete.
 	 * @param keys the keys of the objects to delete.
+	 * @param <T> the type of the object to delete.
 	 */
-	void delete(Class entityClass, KeySet keys);
+	<T> void delete(Class<T> entityClass, KeySet keys);
 
 	/**
 	 * Insert an object into storage.
@@ -192,7 +194,7 @@ <T> List<T> query(Class<T> entityClass, Statement statement,
 	 * Insert objects into storage in batch.
 	 * @param objects the objects to insert.
 	 */
-	void insertAll(Iterable objects);
+	void insertAll(Iterable<?> objects);
 
 	/**
 	 * Update an object already in storage.
@@ -204,7 +206,7 @@ <T> List<T> query(Class<T> entityClass, Statement statement,
 	 * Update objects in batch.
 	 * @param objects the objects to update.
 	 */
-	void updateAll(Iterable objects);
+	void updateAll(Iterable<?> objects);
 
 	/**
 	 * Update an object in storage.
@@ -233,7 +235,7 @@ <T> List<T> query(Class<T> entityClass, Statement statement,
 	 * Update or insert objects into storage in batch.
 	 * @param objects the objects to update or insert.
 	 */
-	void upsertAll(Iterable objects);
+	void upsertAll(Iterable<?> objects);
 
 	/**
 	 * Update or insert an object into storage.
@@ -255,9 +257,10 @@ <T> List<T> query(Class<T> entityClass, Statement statement,
 	/**
 	 * Count how many objects are stored of the given type.
 	 * @param entityClass the type of object to count.
+	 * @param <T> the type of the object to count.
 	 * @return the number of stored objects.
 	 */
-	long count(Class entityClass);
+	<T> long count(Class<T> entityClass);
 
 	/**
 	 * Performs multiple read and write operations in a single transaction.

spring-cloud-gcp-data-spanner/src/main/java/org/springframework/cloud/gcp/data/spanner/core/SpannerTemplate.java

@@ -54,7 +54,6 @@
 import org.springframework.cloud.gcp.data.spanner.core.mapping.SpannerDataException;
 import org.springframework.cloud.gcp.data.spanner.core.mapping.SpannerMappingContext;
 import org.springframework.cloud.gcp.data.spanner.core.mapping.SpannerPersistentEntity;
-import org.springframework.cloud.gcp.data.spanner.core.mapping.SpannerPersistentProperty;
 import org.springframework.cloud.gcp.data.spanner.core.mapping.event.AfterDeleteEvent;
 import org.springframework.cloud.gcp.data.spanner.core.mapping.event.AfterExecuteDmlEvent;
 import org.springframework.cloud.gcp.data.spanner.core.mapping.event.AfterQueryEvent;
@@ -68,7 +67,6 @@
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.context.ApplicationEventPublisherAware;
 import org.springframework.data.mapping.PersistentPropertyAccessor;
-import org.springframework.data.mapping.PropertyHandler;
 import org.springframework.transaction.support.TransactionSynchronizationManager;
 import org.springframework.util.Assert;
 
@@ -274,7 +272,7 @@ public void insert(Object object) {
 
 
 	@Override
-	public void insertAll(Iterable objects) {
+	public void insertAll(Iterable<?> objects) {
 		applySaveMutations(() -> getMutationsForMultipleObjects(objects, this.mutationFactory::insert), objects, null);
 	}
 
@@ -284,7 +282,7 @@ public void update(Object object) {
 	}
 
 	@Override
-	public void updateAll(Iterable objects) {
+	public void updateAll(Iterable<?> objects) {
 		applySaveMutations(() -> getMutationsForMultipleObjects(objects,
 				(x) -> this.mutationFactory.update(x, null)), objects, null);
 	}
@@ -309,7 +307,7 @@ public void upsert(Object object) {
 	}
 
 	@Override
-	public void upsertAll(Iterable objects) {
+	public void upsertAll(Iterable<?> objects) {
 		applySaveMutations(() -> getMutationsForMultipleObjects(objects,
 				(x) -> this.mutationFactory.upsert(x, null)), objects, null);
 	}
@@ -327,7 +325,7 @@ public void upsert(Object object, Set<String> includeProperties) {
 				includeProperties);
 	}
 
-	private void applySaveMutations(Supplier<List<Mutation>> mutationsSupplier, Iterable entities,
+	private void applySaveMutations(Supplier<List<Mutation>> mutationsSupplier, Iterable<?> entities,
 			Set<String> includeProperties) {
 		maybeEmitEvent(new BeforeSaveEvent(entities, includeProperties));
 		List<Mutation> mutations = mutationsSupplier.get();
@@ -342,12 +340,12 @@ public void delete(Object entity) {
 	}
 
 	@Override
-	public void deleteAll(Iterable objects) {
-		applyDeleteMutations(objects, (List<Mutation>) StreamSupport.stream(objects.spliterator(), false)
+	public void deleteAll(Iterable<?> objects) {
+		applyDeleteMutations(objects, StreamSupport.stream(objects.spliterator(), false)
 				.map(this.mutationFactory::delete).collect(Collectors.toList()));
 	}
 
-	private void applyDeleteMutations(Iterable objects, List<Mutation> mutations) {
+	private void applyDeleteMutations(Iterable<?> objects, List<Mutation> mutations) {
 		maybeEmitEvent(new BeforeDeleteEvent(mutations, objects, null, null));
 		applyMutations(mutations);
 		maybeEmitEvent(new AfterDeleteEvent(mutations, objects, null, null));
@@ -452,10 +450,10 @@ private String getQueryLogMessageWithOptions(Statement statement, SpannerQueryOp
 		String message;
 		StringBuilder logSb = new StringBuilder("Executing query");
 		if (options.getTimestampBound() != null) {
-			logSb.append(" at timestamp" + options.getTimestampBound());
+			logSb.append(" at timestamp ").append(options.getTimestampBound());
 		}
-		for (QueryOption queryOption : (QueryOption[]) options.getOptions()) {
-			logSb.append(" with option: " + queryOption);
+		for (QueryOption queryOption : options.getOptions()) {
+			logSb.append(" with option: ").append(queryOption);
 		}
 		logSb.append(" : ").append(statement);
 		message = logSb.toString();
@@ -470,7 +468,7 @@ private ResultSet performQuery(Statement statement, SpannerQueryOptions options)
 		else {
 			resultSet = ((options.getTimestampBound() != null)
 					? getReadContext(options.getTimestampBound())
-					: getReadContext()).executeQuery(statement, (QueryOption[]) options.getOptions());
+					: getReadContext()).executeQuery(statement, options.getOptions());
 		}
 		return resultSet;
 	}
@@ -521,22 +519,22 @@ private void logReadOptions(SpannerReadOptions options, StringBuilder logs) {
 			return;
 		}
 		if (options.getTimestampBound() != null) {
-			logs.append(" at timestamp " + options.getTimestampBound());
+			logs.append(" at timestamp ").append(options.getTimestampBound());
 		}
 		for (ReadOption readOption : options.getOptions()) {
-			logs.append(" with option: " + readOption);
+			logs.append(" with option: ").append(readOption);
 		}
 		if (options.getIndex() != null) {
-			logs.append(" secondary index: " + options.getIndex());
+			logs.append(" secondary index: ").append(options.getIndex());
 		}
 	}
 
 	private StringBuilder logColumns(String tableName, KeySet keys,
 			Iterable<String> columns) {
-		StringBuilder logSb = new StringBuilder("Executing read on table " + tableName
-				+ " with keys: " + keys + " and columns: ");
-		StringJoiner sj = new StringJoiner(",");
-		columns.forEach((col) -> sj.add(col));
+		StringBuilder logSb = new StringBuilder();
+		logSb.append("Executing read on table ").append(tableName).append(" with keys: ").append(keys).append(" and columns: ");
+		StringJoiner sj = new StringJoiner(", ");
+		columns.forEach(sj::add);
 		logSb.append(sj.toString());
 		return logSb;
 	}
@@ -575,12 +573,12 @@ private <T> List<T> resolveChildEntities(List<T> entities,
 	}
 
 	private void resolveChildEntity(Object entity, Set<String> includeProperties) {
-		SpannerPersistentEntity spannerPersistentEntity = this.mappingContext
+		SpannerPersistentEntity<?> spannerPersistentEntity = this.mappingContext
 				.getPersistentEntity(entity.getClass());
-		PersistentPropertyAccessor accessor = spannerPersistentEntity
+		PersistentPropertyAccessor<?> accessor = spannerPersistentEntity
 				.getPropertyAccessor(entity);
 		spannerPersistentEntity.doWithInterleavedProperties(
-				(PropertyHandler<SpannerPersistentProperty>) (spannerPersistentProperty) -> {
+				(spannerPersistentProperty) -> {
 					if (includeProperties != null && !includeProperties
 							.contains(spannerPersistentEntity.getName())) {
 						return;
@@ -609,9 +607,9 @@ private void resolveChildEntity(Object entity, Set<String> includeProperties) {
 				});
 	}
 
-	private List<Mutation> getMutationsForMultipleObjects(Iterable it,
+	private List<Mutation> getMutationsForMultipleObjects(Iterable<?> it,
 			Function<Object, Collection<Mutation>> individualEntityMutationFunc) {
-		return (List<Mutation>) StreamSupport.stream(it.spliterator(), false)
+		return StreamSupport.stream(it.spliterator(), false)
 				.flatMap((x) -> individualEntityMutationFunc.apply(x).stream())
 				.collect(Collectors.toList());
 	}

spring-cloud-gcp-data-spanner/src/main/java/org/springframework/cloud/gcp/data/spanner/core/admin/SpannerDatabaseAdminTemplate.java

@@ -149,16 +149,16 @@ public boolean databaseExists() {
 	 */
 	public Map<String, String> getChildParentTablesMap() {
 		Map<String, String> relationships = new HashMap<>();
-		ResultSet results = this.databaseClientProvider.get().singleUse()
-				.executeQuery(TABLE_AND_PARENT_QUERY);
-		while (results.next()) {
-			Struct row = results.getCurrentRowAsStruct();
-			relationships.put(row.getString(TABLE_NAME_COL_NAME),
-					row.isNull(PARENT_TABLE_NAME_COL_NAME) ? null
-							: row.getString(PARENT_TABLE_NAME_COL_NAME));
+		try (ResultSet results = this.databaseClientProvider.get().singleUse()
+				.executeQuery(TABLE_AND_PARENT_QUERY)) {
+			while (results.next()) {
+				Struct row = results.getCurrentRowAsStruct();
+				relationships.put(row.getString(TABLE_NAME_COL_NAME),
+						row.isNull(PARENT_TABLE_NAME_COL_NAME) ? null
+								: row.getString(PARENT_TABLE_NAME_COL_NAME));
+			}
+			return relationships;
 		}
-		results.close();
-		return relationships;
 	}
 
 	/**

spring-cloud-gcp-data-spanner/src/main/java/org/springframework/cloud/gcp/data/spanner/core/convert/ConversionUtils.java

@@ -61,6 +61,7 @@ static <T> Iterable<T> convertIterable(
 		return result;
 	}
 
+	@SuppressWarnings("unchecked")
 	public static <T> T wrapSimpleLazyProxy(Supplier<T> supplierFunc, Class<T> type) {
 		return (T) Proxy.newProxyInstance(type.getClassLoader(), new Class[] { type },
 				new SimpleLazyDynamicInvocationHandler<>(supplierFunc));
@@ -69,7 +70,7 @@ public static <T> T wrapSimpleLazyProxy(Supplier<T> supplierFunc, Class<T> type)
 	public static boolean ignoreForWriteLazyProxy(Object object) {
 		if (Proxy.isProxyClass(object.getClass())
 				&& (Proxy.getInvocationHandler(object) instanceof SimpleLazyDynamicInvocationHandler)) {
-			SimpleLazyDynamicInvocationHandler handler = (SimpleLazyDynamicInvocationHandler) Proxy
+			SimpleLazyDynamicInvocationHandler<?> handler = (SimpleLazyDynamicInvocationHandler<?>) Proxy
 					.getInvocationHandler(object);
 			return !handler.isEvaluated();
 		}

spring-cloud-gcp-data-spanner/src/main/java/org/springframework/cloud/gcp/data/spanner/core/convert/SpannerEntityProcessor.java

@@ -44,7 +44,7 @@ public interface SpannerEntityProcessor extends SpannerEntityReader, SpannerEnti
 	<T> List<T> mapToList(ResultSet resultSet, Class<T> entityClass);
 
 	/**
-	 * Converts a set of Spanner {@link ResultSet} into a list of objects.
+	 * Converts a Spanner {@link ResultSet} into a list of objects.
 	 * @param resultSet the Spanner results to convert. The ResultSet will be exhausted
 	 * and closed.
 	 * @param entityClass the type of the objects the Spanner results represent.

spring-cloud-gcp-data-spanner/src/main/java/org/springframework/cloud/gcp/data/spanner/core/mapping/event/ExecuteDmlEvent.java

@@ -29,7 +29,7 @@ public class ExecuteDmlEvent extends ApplicationEvent {
 
 	/**
 	 * Constructor.
-	 * @param statement @param statement the DML statement which is (never {@code null})
+	 * @param statement the DML statement which is (never {@code null})
 	 */
 	public ExecuteDmlEvent(Statement statement) {
 		super(statement);

spring-cloud-gcp-data-spanner/src/main/java/org/springframework/cloud/gcp/data/spanner/repository/query/SpannerStatementQueryExecutor.java

@@ -163,7 +163,7 @@ public static <T> String applySortingPagingQueryOptions(Class<T> entityClass,
 	}
 
 	/**
-	 * Gets a query that returns the rows associated with a parent entity. This function is
+	 * Gets a {@link Statement} that returns the rows associated with a parent entity. This function is
 	 * intended to be used with parent-child interleaved tables, so that the retrieval of all
 	 * child rows having the parent's key values is efficient.
 	 * @param parentKey the parent key whose children to get.
@@ -252,7 +252,6 @@ private static <C, P> String getChildrenStructsQuery(
 	 * @throws IllegalArgumentException if the number of tags does not match the number of
 	 *     params, or if a param of an unsupported type is given.
 	 */
-	@SuppressWarnings("unchecked")
 	public static Statement buildStatementFromSqlWithArgs(String sql, List<String> tags,
 			Function<Object, Struct> paramStructConvertFunc, SpannerCustomConverter spannerCustomConverter,
 			Object[] params, Map<String, Parameter> queryMethodParams) {
@@ -271,6 +270,7 @@ public static Statement buildStatementFromSqlWithArgs(String sql, List<String> t
 		return builder.build();
 	}
 
+	@SuppressWarnings("unchecked")
 	private static void bindParameter(ValueBinder<Statement.Builder> bind,
 			Function<Object, Struct> paramStructConvertFunc, SpannerCustomConverter spannerCustomConverter,
 			Object originalParam, Parameter paramMetadata) {
@@ -301,14 +301,15 @@ private static void bindParameter(ValueBinder<Statement.Builder> bind,
 		}
 	}
 
-	public static String getColumnsStringForSelect(SpannerPersistentEntity spannerPersistentEntity, SpannerMappingContext mappingContext) {
+	public static String getColumnsStringForSelect(
+			SpannerPersistentEntity<?> spannerPersistentEntity, SpannerMappingContext mappingContext) {
 		StringJoiner joiner = new StringJoiner(", ");
-		spannerPersistentEntity.doWithInterleavedProperties(persistentProperty -> {
-			SpannerPersistentProperty spannerPersistentProperty = (SpannerPersistentProperty) persistentProperty;
+		spannerPersistentEntity.doWithInterleavedProperties(spannerPersistentProperty -> {
 			if (spannerPersistentProperty.isEagerInterleaved()) {
 				Class childType = spannerPersistentProperty.getColumnInnerType();
 				SpannerPersistentEntity childPersistentEntity = mappingContext.getPersistentEntity(childType);
-				joiner.add(getChildrenStructsQuery(childPersistentEntity, spannerPersistentEntity, mappingContext, spannerPersistentProperty.getColumnName()));
+				joiner.add(getChildrenStructsQuery(
+					childPersistentEntity, spannerPersistentEntity, mappingContext, spannerPersistentProperty.getColumnName()));
 			}
 		});
 		String childrenSubquery = joiner.toString();
@@ -344,17 +345,16 @@ else if (tree.isExistsProjection()) {
 		return Pair.of(finalSql, tags);
 	}
 
-	private static StringBuilder buildSelect(
-			SpannerPersistentEntity spannerPersistentEntity, PartTree tree,
+	private static void buildSelect(
+			SpannerPersistentEntity<?> spannerPersistentEntity, PartTree tree,
 			StringBuilder stringBuilder, SpannerMappingContext mappingContext) {
-		stringBuilder.append("SELECT " + (tree.isDistinct() ? "DISTINCT " : "")
-				+ getColumnsStringForSelect(spannerPersistentEntity, mappingContext) + " ");
-		return stringBuilder;
+		stringBuilder.append("SELECT ").append(tree.isDistinct() ? "DISTINCT " : "")
+				.append(getColumnsStringForSelect(spannerPersistentEntity, mappingContext)).append(" ");
 	}
 
 	private static void buildFrom(SpannerPersistentEntity<?> persistentEntity,
 			StringBuilder stringBuilder) {
-		stringBuilder.append("FROM " + persistentEntity.tableName() + " ");
+		stringBuilder.append("FROM ").append(persistentEntity.tableName()).append(" ");
 	}
 
 	public static StringBuilder applySort(Sort sort, StringBuilder sql,
@@ -484,7 +484,7 @@ private static void buildLimit(PartTree tree, StringBuilder stringBuilder) {
 			stringBuilder.append(" LIMIT 1");
 		}
 		else if (tree.isLimiting()) {
-			stringBuilder.append(" LIMIT " + tree.getMaxResults());
+			stringBuilder.append(" LIMIT ").append(tree.getMaxResults());
 		}
 	}
 }