Properly convert Map keys.

Keys of maps now get properly converted.
Among others this enables the use of enums as keys.

Closes #1656
Original pull request: #1663

spring-data-jdbc/src/main/java/org/springframework/data/jdbc/core/JdbcAggregateChangeExecutionContext.java

@@ -245,7 +245,7 @@ class JdbcAggregateChangeExecutionContext {
 		RelationalPersistentEntity<?> persistentEntity = getRequiredPersistentEntity(idOwningAction.getEntityType());
 		Object identifier = persistentEntity.getIdentifierAccessor(idOwningAction.getEntity()).getIdentifier();
 
-		Assert.state(identifier != null, "Couldn't obtain a required id value");
+		Assert.state(identifier != null,() -> "Couldn't obtain a required id value for " + persistentEntity);
 
 		return identifier;
 	}

spring-data-jdbc/src/main/java/org/springframework/data/jdbc/core/convert/MapEntityRowMapper.java

@@ -23,7 +23,9 @@ import java.util.Map;
 import org.springframework.data.relational.core.mapping.PersistentPropertyPathExtension;
 import org.springframework.data.relational.core.sql.IdentifierProcessing;
 import org.springframework.data.relational.core.sql.SqlIdentifier;
+import org.springframework.data.util.TypeInformation;
 import org.springframework.jdbc.core.RowMapper;
+import org.springframework.jdbc.support.JdbcUtils;
 
 /**
  * A {@link RowMapper} that maps a row to a {@link Map.Entry} so an {@link Iterable} of those can be converted to a
@@ -50,8 +52,11 @@ class MapEntityRowMapper<T> implements RowMapper<Map.Entry<Object, T>> {
 	@Override
 	public Map.Entry<Object, T> mapRow(ResultSet rs, int rowNum) throws SQLException {
 
-		Object key = rs.getObject(keyColumn.getReference());
-		return new HashMap.SimpleEntry<>(key, mapEntity(rs, key));
+		Object key = new ResultSetAccessor(rs).getObject(keyColumn.getReference());
+		Class<?> qualifierColumnType = path.getRequiredPersistentPropertyPath().getLeafProperty().getQualifierColumnType();
+		Object convertedKey = converter.readValue(key, TypeInformation.of(qualifierColumnType));
+
+		return new HashMap.SimpleEntry<>(convertedKey, mapEntity(rs, key));
 	}
 
 	private T mapEntity(ResultSet resultSet, Object key) {

spring-data-jdbc/src/test/java/org/springframework/data/jdbc/core/JdbcAggregateTemplateIntegrationTests.java

@@ -1095,6 +1095,16 @@ class JdbcAggregateTemplateIntegrationTests {
 		assertThat(template.findById(entity.id, EnumArrayOwner.class).digits).isEqualTo(new Color[]{Color.BLUE});
 	}
 
+	@Test // GH-1656
+	void mapWithEnumKey() {
+
+		EnumMapOwner enumMapOwner = template.save(new EnumMapOwner(null, "OwnerName", Map.of(Color.BLUE, new MapElement("Element"))));
+
+		Iterable<EnumMapOwner> enumMapOwners = template.findAll(EnumMapOwner.class);
+
+		assertThat(enumMapOwners).containsExactly(enumMapOwner);
+	}
+
 	private <T extends Number> void saveAndUpdateAggregateWithVersion(VersionedAggregate aggregate,
 			Function<Number, T> toConcreteNumber) {
 		saveAndUpdateAggregateWithVersion(aggregate, toConcreteNumber, 0);
@@ -1548,6 +1558,12 @@ class JdbcAggregateTemplateIntegrationTests {
 		String insertOnly;
 	}
 
+	record EnumMapOwner(@Id Long id, String name, Map<Color, MapElement> map) {
+	}
+
+	record MapElement(String name) {
+	}
+
 	@Configuration
 	@Import(TestConfiguration.class)
 	static class Config {

spring-data-jdbc/src/test/resources/org.springframework.data.jdbc.core/JdbcAggregateTemplateIntegrationTests-db2.sql

@@ -41,6 +41,9 @@ DROP TABLE WITH_ID_ONLY;
 
 DROP TABLE WITH_INSERT_ONLY;
 
+DROP TABLE MAP_ELEMENT;
+DROP TABLE ENUM_MAP_OWNER;
+
 CREATE TABLE LEGO_SET
 (
     "id1" BIGINT GENERATED BY DEFAULT AS IDENTITY (START WITH 1) PRIMARY KEY,
@@ -366,3 +369,18 @@ CREATE TABLE WITH_INSERT_ONLY
     ID          BIGINT GENERATED BY DEFAULT AS IDENTITY (START WITH 1) PRIMARY KEY,
     INSERT_ONLY VARCHAR(100)
 );
+
+CREATE TABLE MAP_ELEMENT
+(
+    MULTIPLE_COLLECTIONS     BIGINT,
+    MULTIPLE_COLLECTIONS_KEY VARCHAR(10),
+    ENUM_MAP_OWNER           BIGINT,
+    ENUM_MAP_OWNER_KEY       VARCHAR(10),
+    NAME                     VARCHAR(100)
+);
+
+CREATE TABLE ENUM_MAP_OWNER
+(
+    ID   BIGINT GENERATED BY DEFAULT AS IDENTITY (START WITH 1) PRIMARY KEY,
+    NAME VARCHAR(100)
+);

spring-data-jdbc/src/test/resources/org.springframework.data.jdbc.core/JdbcAggregateTemplateIntegrationTests-h2.sql

@@ -333,3 +333,18 @@ CREATE TABLE WITH_INSERT_ONLY
     ID          SERIAL PRIMARY KEY,
     INSERT_ONLY VARCHAR(100)
 );
+
+CREATE TABLE MAP_ELEMENT
+(
+    MULTIPLE_COLLECTIONS     BIGINT,
+    MULTIPLE_COLLECTIONS_KEY VARCHAR(10),
+    ENUM_MAP_OWNER           BIGINT,
+    ENUM_MAP_OWNER_KEY       VARCHAR(10),
+    NAME                     VARCHAR(100)
+);
+
+CREATE TABLE ENUM_MAP_OWNER
+(
+    ID   SERIAL PRIMARY KEY,
+    NAME VARCHAR(100)
+);

spring-data-jdbc/src/test/resources/org.springframework.data.jdbc.core/JdbcAggregateTemplateIntegrationTests-hsql.sql

@@ -334,4 +334,19 @@ CREATE TABLE WITH_INSERT_ONLY
 CREATE TABLE WITH_ID_ONLY
 (
     ID BIGINT GENERATED BY DEFAULT AS IDENTITY (START WITH 1) PRIMARY KEY
-)
+);
+
+CREATE TABLE MAP_ELEMENT
+(
+    MULTIPLE_COLLECTIONS     BIGINT,
+    MULTIPLE_COLLECTIONS_KEY VARCHAR(10),
+    ENUM_MAP_OWNER           BIGINT,
+    ENUM_MAP_OWNER_KEY       VARCHAR(10),
+    NAME                     VARCHAR(100)
+);
+
+CREATE TABLE ENUM_MAP_OWNER
+(
+    ID   BIGINT GENERATED BY DEFAULT AS IDENTITY (START WITH 1) PRIMARY KEY,
+    NAME VARCHAR(100)
+);

spring-data-jdbc/src/test/resources/org.springframework.data.jdbc.core/JdbcAggregateTemplateIntegrationTests-mariadb.sql

@@ -308,3 +308,18 @@ CREATE TABLE WITH_INSERT_ONLY
     ID          BIGINT AUTO_INCREMENT PRIMARY KEY,
     INSERT_ONLY VARCHAR(100)
 );
+
+CREATE TABLE MAP_ELEMENT
+(
+    MULTIPLE_COLLECTIONS     BIGINT,
+    MULTIPLE_COLLECTIONS_KEY VARCHAR(10),
+    ENUM_MAP_OWNER           BIGINT,
+    ENUM_MAP_OWNER_KEY       VARCHAR(10),
+    NAME                     VARCHAR(100)
+);
+
+CREATE TABLE ENUM_MAP_OWNER
+(
+    ID   BIGINT AUTO_INCREMENT PRIMARY KEY,
+    NAME VARCHAR(100)
+);

spring-data-jdbc/src/test/resources/org.springframework.data.jdbc.core/JdbcAggregateTemplateIntegrationTests-mssql.sql

@@ -340,3 +340,20 @@ CREATE TABLE WITH_INSERT_ONLY
     ID          BIGINT IDENTITY PRIMARY KEY,
     INSERT_ONLY VARCHAR(100)
 );
+
+DROP TABLE MAP_ELEMENT;
+CREATE TABLE MAP_ELEMENT
+(
+    MULTIPLE_COLLECTIONS     BIGINT,
+    MULTIPLE_COLLECTIONS_KEY VARCHAR(10),
+    ENUM_MAP_OWNER           BIGINT,
+    ENUM_MAP_OWNER_KEY       VARCHAR(10),
+    NAME                     VARCHAR(100)
+);
+
+DROP TABLE ENUM_MAP_OWNER;
+CREATE TABLE ENUM_MAP_OWNER
+(
+    ID   BIGINT IDENTITY PRIMARY KEY,
+    NAME VARCHAR(100)
+);

spring-data-jdbc/src/test/resources/org.springframework.data.jdbc.core/JdbcAggregateTemplateIntegrationTests-mysql.sql

@@ -313,3 +313,18 @@ CREATE TABLE WITH_INSERT_ONLY
     ID          BIGINT AUTO_INCREMENT PRIMARY KEY,
     INSERT_ONLY VARCHAR(100)
 );
+
+CREATE TABLE MAP_ELEMENT
+(
+    MULTIPLE_COLLECTIONS     BIGINT,
+    MULTIPLE_COLLECTIONS_KEY VARCHAR(10),
+    ENUM_MAP_OWNER           BIGINT,
+    ENUM_MAP_OWNER_KEY       VARCHAR(10),
+    NAME                     VARCHAR(100)
+);
+
+CREATE TABLE ENUM_MAP_OWNER
+(
+    ID   BIGINT AUTO_INCREMENT PRIMARY KEY,
+    NAME VARCHAR(100)
+);

spring-data-jdbc/src/test/resources/org.springframework.data.jdbc.core/JdbcAggregateTemplateIntegrationTests-oracle.sql

@@ -31,6 +31,9 @@ DROP TABLE WITH_LOCAL_DATE_TIME CASCADE CONSTRAINTS PURGE;
 DROP TABLE WITH_ID_ONLY CASCADE CONSTRAINTS PURGE;
 DROP TABLE WITH_INSERT_ONLY CASCADE CONSTRAINTS PURGE;
 
+DROP TABLE MAP_ELEMENT CASCADE CONSTRAINTS PURGE;
+DROP TABLE ENUM_MAP_OWNER CASCADE CONSTRAINTS PURGE;
+
 CREATE TABLE LEGO_SET
 (
     "id1" NUMBER GENERATED by default on null as IDENTITY PRIMARY KEY,
@@ -347,3 +350,18 @@ CREATE TABLE WITH_INSERT_ONLY
     ID          NUMBER GENERATED by default on null as IDENTITY PRIMARY KEY,
     INSERT_ONLY VARCHAR(100)
 );
+
+CREATE TABLE MAP_ELEMENT
+(
+    MULTIPLE_COLLECTIONS     NUMBER,
+    MULTIPLE_COLLECTIONS_KEY VARCHAR(10),
+    ENUM_MAP_OWNER           BIGINT,
+    ENUM_MAP_OWNER_KEY       VARCHAR(10),
+    NAME                     VARCHAR(100)
+);
+
+CREATE TABLE ENUM_MAP_OWNER
+(
+    ID   BIGINT GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY,
+    NAME VARCHAR(100)
+);

spring-data-jdbc/src/test/resources/org.springframework.data.jdbc.core/JdbcAggregateTemplateIntegrationTests-postgres.sql

@@ -15,6 +15,9 @@ DROP TABLE WITH_READ_ONLY;
 DROP TABLE WITH_ID_ONLY;
 DROP TABLE WITH_INSERT_ONLY;
 
+DROP TABLE MAP_ELEMENT;
+DROP TABLE ENUM_MAP_OWNER;
+
 CREATE TABLE LEGO_SET
 (
     "id1" SERIAL PRIMARY KEY,
@@ -349,3 +352,18 @@ CREATE TABLE WITH_INSERT_ONLY
     ID          SERIAL PRIMARY KEY,
     INSERT_ONLY VARCHAR(100)
 );
+
+CREATE TABLE MAP_ELEMENT
+(
+    MULTIPLE_COLLECTIONS     BIGINT,
+    MULTIPLE_COLLECTIONS_KEY VARCHAR(10),
+    ENUM_MAP_OWNER           BIGINT,
+    ENUM_MAP_OWNER_KEY       VARCHAR(10),
+    NAME                     VARCHAR(100)
+);
+
+CREATE TABLE ENUM_MAP_OWNER
+(
+    ID   BIGINT GENERATED BY DEFAULT AS IDENTITY (START WITH 1) PRIMARY KEY,
+    NAME VARCHAR(100)
+);