Polishing.

Refactor convertAndAddParameter method to writeValue(…) decoupling responsibilities for a clearer value conversion code path. Also, refactor collection conversion to functional callback-style and extend test assertions.

See #1323
Original pull request: #1838

spring-data-jdbc/src/main/java/org/springframework/data/jdbc/repository/query/StringBasedJdbcQuery.java

@@ -23,21 +23,18 @@ import java.sql.JDBCType;
 import java.sql.SQLType;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.LinkedHashMap;
 import java.util.List;
-import java.util.Map;
 import java.util.function.Function;
 import java.util.function.Supplier;
 
 import org.springframework.beans.BeanInstantiationException;
 import org.springframework.beans.BeanUtils;
 import org.springframework.beans.factory.BeanFactory;
-import org.springframework.data.jdbc.core.convert.JdbcColumnTypes;
 import org.springframework.data.jdbc.core.convert.JdbcConverter;
 import org.springframework.data.jdbc.core.mapping.JdbcValue;
-import org.springframework.data.jdbc.support.JdbcUtil;
 import org.springframework.data.relational.core.mapping.RelationalMappingContext;
 import org.springframework.data.relational.repository.query.RelationalParameterAccessor;
-import org.springframework.data.relational.repository.query.RelationalParameters;
 import org.springframework.data.relational.repository.query.RelationalParametersParameterAccessor;
 import org.springframework.data.repository.query.Parameter;
 import org.springframework.data.repository.query.Parameters;
@@ -47,7 +44,6 @@ import org.springframework.data.repository.query.SpelEvaluator;
 import org.springframework.data.repository.query.SpelQueryContext;
 import org.springframework.data.util.Lazy;
 import org.springframework.data.util.TypeInformation;
-import org.springframework.data.util.TypeUtils;
 import org.springframework.jdbc.core.ResultSetExtractor;
 import org.springframework.jdbc.core.RowMapper;
 import org.springframework.jdbc.core.namedparam.MapSqlParameterSource;
@@ -55,7 +51,6 @@ import org.springframework.jdbc.core.namedparam.NamedParameterJdbcOperations;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
-import org.springframework.util.ConcurrentReferenceHashMap;
 import org.springframework.util.ObjectUtils;
 
 /**
@@ -75,7 +70,7 @@ import org.springframework.util.ObjectUtils;
  */
 public class StringBasedJdbcQuery extends AbstractJdbcQuery {
 
-	private static final String PARAMETER_NEEDS_TO_BE_NAMED = "For queries with named parameters you need to provide names for method parameters; Use @Param for query method parameters, or when on Java 8+ use the javac flag -parameters";
+	private static final String PARAMETER_NEEDS_TO_BE_NAMED = "For queries with named parameters you need to provide names for method parameters; Use @Param for query method parameters, or use the javac flag -parameters";
 	private final JdbcConverter converter;
 	private final RowMapperFactory rowMapperFactory;
 	private final SpelEvaluator spelEvaluator;
@@ -188,77 +183,103 @@ public class StringBasedJdbcQuery extends AbstractJdbcQuery {
 
 	private MapSqlParameterSource bindParameters(RelationalParameterAccessor accessor) {
 
-		MapSqlParameterSource parameters = new MapSqlParameterSource();
-
 		Parameters<?, ?> bindableParameters = accessor.getBindableParameters();
+		MapSqlParameterSource parameters = new MapSqlParameterSource(
+				new LinkedHashMap<>(bindableParameters.getNumberOfParameters(), 1.0f));
 
 		for (Parameter bindableParameter : bindableParameters) {
-			convertAndAddParameter(parameters, bindableParameter, accessor.getBindableValue(bindableParameter.getIndex()));
+
+			Object value = accessor.getBindableValue(bindableParameter.getIndex());
+			String parameterName = bindableParameter.getName()
+					.orElseThrow(() -> new IllegalStateException(PARAMETER_NEEDS_TO_BE_NAMED));
+			JdbcParameters.JdbcParameter parameter = getQueryMethod().getParameters()
+					.getParameter(bindableParameter.getIndex());
+
+			JdbcValue jdbcValue = writeValue(value, parameter.getTypeInformation(), parameter);
+			SQLType jdbcType = jdbcValue.getJdbcType();
+
+			if (jdbcType == null) {
+				parameters.addValue(parameterName, jdbcValue.getValue());
+			} else {
+				parameters.addValue(parameterName, jdbcValue.getValue(), jdbcType.getVendorTypeNumber());
+			}
 		}
 
 		return parameters;
 	}
 
-	private void convertAndAddParameter(MapSqlParameterSource parameters, Parameter p, Object value) {
+	private JdbcValue writeValue(@Nullable Object value, TypeInformation<?> typeInformation,
+			JdbcParameters.JdbcParameter parameter) {
 
-		String parameterName = p.getName().orElseThrow(() -> new IllegalStateException(PARAMETER_NEEDS_TO_BE_NAMED));
+		if (value == null) {
+			return JdbcValue.of(value, parameter.getSqlType());
+		}
 
-		JdbcParameters.JdbcParameter parameter = getQueryMethod().getParameters().getParameter(p.getIndex());
-		TypeInformation<?> typeInformation = parameter.getTypeInformation();
+		if (typeInformation.isCollectionLike() && value instanceof Collection<?> collection) {
 
-		JdbcValue jdbcValue;
-		if (typeInformation.isCollectionLike() //
-				&& value instanceof Collection<?> collectionValue//
-		) {
-			if ( typeInformation.getActualType().getType().isArray() ){
+			TypeInformation<?> actualType = typeInformation.getActualType();
 
-				TypeInformation<?> arrayElementType = typeInformation.getActualType().getActualType();
+			// tuple-binding
+			if (actualType != null && actualType.getType().isArray()) {
 
-				List<Object[]> mapped = new ArrayList<>();
+				TypeInformation<?> nestedElementType = actualType.getRequiredActualType();
+				return writeCollection(collection, JDBCType.OTHER,
+						array -> writeArrayValue(parameter, array, nestedElementType));
+			}
 
-				for (Object array : collectionValue) {
-					int length = Array.getLength(array);
-					Object[] mappedArray = new Object[length];
+			// parameter expansion
+			return writeCollection(collection, parameter.getActualSqlType(),
+					it -> converter.writeJdbcValue(it, typeInformation.getRequiredActualType(), parameter.getActualSqlType()));
+		}
 
-					for (int i = 0; i < length; i++) {
-						Object element = Array.get(array, i);
-						JdbcValue elementJdbcValue = converter.writeJdbcValue(element, arrayElementType, parameter.getActualSqlType());
+		SQLType sqlType = parameter.getSqlType();
+		return converter.writeJdbcValue(value, typeInformation, sqlType);
+	}
 
-						mappedArray[i] = elementJdbcValue.getValue();
-					}
-					mapped.add(mappedArray);
-				}
-				jdbcValue = JdbcValue.of(mapped, JDBCType.OTHER);
+	private JdbcValue writeCollection(Collection<?> value, SQLType defaultType, Function<Object, Object> mapper) {
 
-			} else {
-				List<Object> mapped = new ArrayList<>();
-				SQLType jdbcType = null;
+		if (value.isEmpty()) {
+			return JdbcValue.of(value, defaultType);
+		}
 
-				TypeInformation<?> actualType = typeInformation.getRequiredActualType();
-				for (Object o : collectionValue) {
-					JdbcValue elementJdbcValue = converter.writeJdbcValue(o, actualType, parameter.getActualSqlType());
-					if (jdbcType == null) {
-						jdbcType = elementJdbcValue.getJdbcType();
-					}
+		JdbcValue jdbcValue;
+		List<Object> mapped = new ArrayList<>(value.size());
+		SQLType jdbcType = null;
 
-					mapped.add(elementJdbcValue.getValue());
-				}
+		for (Object o : value) {
 
-				jdbcValue = JdbcValue.of(mapped, jdbcType);
+			Object mappedValue = mapper.apply(o);
+
+			if (mappedValue instanceof JdbcValue jv) {
+				if (jdbcType == null) {
+					jdbcType = jv.getJdbcType();
+				}
+				mappedValue = jv.getValue();
 			}
-		} else {
 
-			SQLType sqlType = parameter.getSqlType();
-			jdbcValue = converter.writeJdbcValue(value, typeInformation, sqlType);
+			mapped.add(mappedValue);
 		}
 
-		SQLType jdbcType = jdbcValue.getJdbcType();
-		if (jdbcType == null) {
+		jdbcValue = JdbcValue.of(mapped, jdbcType == null ? defaultType : jdbcType);
 
-			parameters.addValue(parameterName, jdbcValue.getValue());
-		} else {
-			parameters.addValue(parameterName, jdbcValue.getValue(), jdbcType.getVendorTypeNumber());
+		return jdbcValue;
+	}
+
+	private Object[] writeArrayValue(JdbcParameters.JdbcParameter parameter, Object array,
+			TypeInformation<?> nestedElementType) {
+
+		int length = Array.getLength(array);
+		Object[] mappedArray = new Object[length];
+
+		for (int i = 0; i < length; i++) {
+
+			Object element = Array.get(array, i);
+			JdbcValue elementJdbcValue = converter.writeJdbcValue(element, nestedElementType, parameter.getActualSqlType());
+
+			mappedArray[i] = elementJdbcValue.getValue();
 		}
+
+		return mappedArray;
 	}
 
 	RowMapper<Object> determineRowMapper(ResultProcessor resultProcessor, boolean hasDynamicProjection) {

spring-data-jdbc/src/test/java/org/springframework/data/jdbc/repository/JdbcRepositoryIntegrationTests.java

@@ -1350,7 +1350,9 @@ public class JdbcRepositoryIntegrationTests {
 				new Object[]{three.idProp, "two"} // matches nothing
 		);
 
-		repository.findByListInTuple(tuples);
+		List<DummyEntity> result = repository.findByListInTuple(tuples);
+
+		assertThat(result).containsOnly(two);
 	}
 
 	private Root createRoot(String namePrefix) {