Refactoring.

Clarified nullabillity for Identifier.
Removed usage of deprecated constructor for StringBasedJdbcQuery.

Original pull request #1901

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

@@ -24,6 +24,7 @@ import java.util.Map;
 import java.util.Objects;
 
 import org.springframework.data.relational.core.sql.SqlIdentifier;
+import org.springframework.lang.NonNull;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
@@ -60,17 +61,16 @@ public final class Identifier {
 	 * Creates an {@link Identifier} from {@code name}, {@code value}, and a {@link Class target type}.
 	 *
 	 * @param name must not be {@literal null} or empty.
-	 * @param value
+	 * @param value must not be null
 	 * @param targetType must not be {@literal null}.
 	 * @return the {@link Identifier} for {@code name}, {@code value}, and a {@link Class target type}.
 	 */
 	public static Identifier of(SqlIdentifier name, Object value, Class<?> targetType) {
 
 		Assert.notNull(name, "Name must not be empty");
+		Assert.notNull(value, "Value must not be empty");
 		Assert.notNull(targetType, "Target type must not be null");
 
-		// TODO: Is value allowed to be null? SingleIdentifierValue says so, but this type doesn't allows it and
-		// SqlParametersFactory.lambda$forQueryByIdentifier$1 fails with a NPE.
 		return new Identifier(Collections.singletonList(new SingleIdentifierValue(name, value, targetType)));
 	}
 
@@ -92,7 +92,8 @@ public final class Identifier {
 
 		map.forEach((k, v) -> {
 
-			values.add(new SingleIdentifierValue(k, v, v != null ? ClassUtils.getUserClass(v) : Object.class));
+			Assert.notNull(v, "The source map for identifier cannot contain null values");
+			values.add(new SingleIdentifierValue(k, v, ClassUtils.getUserClass(v)));
 		});
 
 		return new Identifier(Collections.unmodifiableList(values));
@@ -199,9 +200,10 @@ public final class Identifier {
 		private final Object value;
 		private final Class<?> targetType;
 
-		private SingleIdentifierValue(SqlIdentifier name, @Nullable Object value, Class<?> targetType) {
+		private SingleIdentifierValue(SqlIdentifier name, Object value, Class<?> targetType) {
 
 			Assert.notNull(name, "Name must not be null");
+			Assert.notNull(value, "Name must not be null");
 			Assert.notNull(targetType, "TargetType must not be null");
 
 			this.name = name;

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

@@ -40,8 +40,7 @@ public class JdbcIdentifierBuilder {
 	/**
 	 * Creates ParentKeys with backreference for the given path and value of the parents id.
 	 */
-	public static JdbcIdentifierBuilder forBackReferences(JdbcConverter converter, AggregatePath path,
+	public static JdbcIdentifierBuilder forBackReferences(JdbcConverter converter, AggregatePath path, Object value) {
-			@Nullable Object value) {
 
 		Identifier identifier = Identifier.of( //
 				path.getTableInfo().reverseColumnInfo().name(), //

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

@@ -92,7 +92,7 @@ public class StringBasedJdbcQuery extends AbstractJdbcQuery {
 	public StringBasedJdbcQuery(JdbcQueryMethod queryMethod, NamedParameterJdbcOperations operations,
 			@Nullable RowMapper<?> defaultRowMapper, JdbcConverter converter,
 			QueryMethodEvaluationContextProvider evaluationContextProvider) {
-		this(queryMethod, operations, result -> (RowMapper<Object>) defaultRowMapper, converter, evaluationContextProvider);
+		this(queryMethod.getRequiredQuery(), queryMethod, operations, result -> (RowMapper<Object>) defaultRowMapper, converter, evaluationContextProvider);
 	}
 
 	/**

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

@@ -50,14 +50,16 @@ public class IdentifierUnitTests {
 	public void parametersWithStringKeysUseObjectAsTypeForNull() {
 
 		HashMap<SqlIdentifier, Object> parameters = new HashMap<>();
-		parameters.put(unquoted("one"), null);
+		Object value = new Object();
+
+		parameters.put(unquoted("one"), value);
 
 		Identifier identifier = Identifier.from(parameters);
 
 		assertThat(identifier.getParts()) //
 				.extracting("name", "value", "targetType") //
 				.containsExactly( //
-						Assertions.tuple(unquoted("one"), null, Object.class) //
+						Assertions.tuple(unquoted("one"), value, Object.class) //
 				);
 	}
 

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

@@ -397,7 +397,7 @@ class StringBasedJdbcQueryUnitTests {
 							mock(RelationResolver.class))
 					: this.converter;
 
-			StringBasedJdbcQuery query = new StringBasedJdbcQuery(method, operations, result -> mock(RowMapper.class),
+			StringBasedJdbcQuery query = new StringBasedJdbcQuery(method.getDeclaredQuery(), method, operations, result -> mock(RowMapper.class),
 					converter, evaluationContextProvider);
 
 			query.execute(arguments);