GenericSqlQuery configured with RowMapper instance

Issue: SPR-14489

spring-jdbc/src/main/java/org/springframework/jdbc/object/GenericSqlQuery.java

 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,43 +18,57 @@ package org.springframework.jdbc.object;
 
 import java.util.Map;
 
-import org.springframework.dao.InvalidDataAccessResourceUsageException;
+import org.springframework.beans.BeanUtils;
 import org.springframework.jdbc.core.RowMapper;
 import org.springframework.util.Assert;
 
+/**
+ * A concrete variant of {@link SqlQuery} which can be configured
+ * with a {@link RowMapper}.
+ *
+ * @author Thomas Risberg
+ * @author Juergen Hoeller
+ * @since 3.0
+ * @see #setRowMapper
+ * @see #setRowMapperClass
+ */
 public class GenericSqlQuery<T> extends SqlQuery<T> {
 
-	Class<?> rowMapperClass;
+	private RowMapper<T> rowMapper;
+
+	@SuppressWarnings("rawtypes")
+	private Class<? extends RowMapper> rowMapperClass;
+
 
-	RowMapper<?> rowMapper;
+	/**
+	 * Set a specific {@link RowMapper} instance to use for this query.
+	 * @since 4.3.2
+	 */
+	public void setRowMapper(RowMapper<T> rowMapper) {
+		this.rowMapper = rowMapper;
+	}
 
+	/**
+	 * Set a {@link RowMapper} class for this query, creating a fresh
+	 * {@link RowMapper} instance per execution.
+	 */
 	@SuppressWarnings("rawtypes")
-	public void setRowMapperClass(Class<? extends RowMapper> rowMapperClass)
-			throws IllegalAccessException, InstantiationException {
+	public void setRowMapperClass(Class<? extends RowMapper> rowMapperClass) {
 		this.rowMapperClass = rowMapperClass;
-		if (!RowMapper.class.isAssignableFrom(rowMapperClass))
-			throw new IllegalStateException("The specified class '" +
-					rowMapperClass.getName() + " is not a sub class of " +
-					"'org.springframework.jdbc.core.RowMapper'");
 	}
 
 	@Override
 	public void afterPropertiesSet() {
 		super.afterPropertiesSet();
-		Assert.notNull(rowMapperClass, "The 'rowMapperClass' property is required");
+		Assert.isTrue(this.rowMapper != null || this.rowMapperClass != null,
+				"'rowMapper' or 'rowMapperClass' is required");
 	}
 
+
 	@Override
 	@SuppressWarnings("unchecked")
 	protected RowMapper<T> newRowMapper(Object[] parameters, Map<?, ?> context) {
-		try {
-			return (RowMapper<T>) rowMapperClass.newInstance();
-		}
-		catch (InstantiationException e) {
-			throw new InvalidDataAccessResourceUsageException("Unable to instantiate RowMapper", e);
-		}
-		catch (IllegalAccessException e) {
-			throw new InvalidDataAccessResourceUsageException("Unable to instantiate RowMapper", e);
-		}
+		return (this.rowMapper != null ? this.rowMapper : BeanUtils.instantiateClass(this.rowMapperClass));
 	}
+
 }

spring-jdbc/src/test/java/org/springframework/jdbc/object/GenericSqlQueryTests.java

@@ -16,7 +16,6 @@
 
 package org.springframework.jdbc.object;
 
-
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
@@ -43,11 +42,12 @@ import static org.mockito.BDDMockito.*;
 
 /**
  * @author Thomas Risberg
+ * @author Juergen Hoeller
  */
 public class GenericSqlQueryTests  {
 
 	private static final String SELECT_ID_FORENAME_NAMED_PARAMETERS_PARSED =
-		"select id, forename from custmr where id = ? and country = ?";
+			"select id, forename from custmr where id = ? and country = ?";
 
 	private BeanFactory beanFactory;
 
@@ -57,6 +57,7 @@ public class GenericSqlQueryTests  {
 
 	private ResultSet resultSet;
 
+
 	@Before
 	public void setUp() throws Exception {
 		this.beanFactory = new DefaultListableBeanFactory();
@@ -72,17 +73,23 @@ public class GenericSqlQueryTests  {
 	}
 
 	@Test
-	public void testPlaceHoldersCustomerQuery() throws SQLException {
-		SqlQuery<?> query = (SqlQuery<?>) beanFactory.getBean("queryWithPlaceHolders");
+	public void testCustomerQueryWithPlaceholders() throws SQLException {
+		SqlQuery<?> query = (SqlQuery<?>) beanFactory.getBean("queryWithPlaceholders");
 		doTestCustomerQuery(query, false);
 	}
 
 	@Test
-	public void testNamedParameterCustomerQuery() throws SQLException {
+	public void testCustomerQueryWithNamedParameters() throws SQLException {
 		SqlQuery<?> query = (SqlQuery<?>) beanFactory.getBean("queryWithNamedParameters");
 		doTestCustomerQuery(query, true);
 	}
 
+	@Test
+	public void testCustomerQueryWithRowMapperInstance() throws SQLException {
+		SqlQuery<?> query = (SqlQuery<?>) beanFactory.getBean("queryWithRowMapperBean");
+		doTestCustomerQuery(query, true);
+	}
+
 	private void doTestCustomerQuery(SqlQuery<?> query, boolean namedParameters) throws SQLException {
 		given(resultSet.next()).willReturn(true);
 		given(resultSet.getInt("id")).willReturn(1);

spring-jdbc/src/test/resources/org/springframework/jdbc/object/GenericSqlQueryTests-context.xml

@@ -6,7 +6,7 @@
 
 	<bean id="dataSource" class="org.springframework.jdbc.datasource.TestDataSourceWrapper"/>
 
-	<bean id="queryWithPlaceHolders" class="org.springframework.jdbc.object.GenericSqlQuery">
+	<bean id="queryWithPlaceholders" class="org.springframework.jdbc.object.GenericSqlQuery">
 		<property name="dataSource" ref="dataSource"/>
 		<property name="sql" value="select id, forename from custmr where id = ? and country = ?"/>
 		<property name="parameters">
@@ -50,4 +50,28 @@
     <property name="rowMapperClass" value="org.springframework.jdbc.object.CustomerMapper"/>
 	</bean>
 
+	<bean id="queryWithRowMapperBean" class="org.springframework.jdbc.object.GenericSqlQuery">
+		<property name="dataSource" ref="dataSource"/>
+		<property name="sql" value="select id, forename from custmr where id = :id and country = :country"/>
+		<property name="parameters">
+			<list>
+				<bean class="org.springframework.jdbc.core.SqlParameter">
+					<constructor-arg index="0" value="id"/>
+					<constructor-arg index="1">
+						<util:constant static-field="java.sql.Types.INTEGER"/>
+					</constructor-arg>
+				</bean>
+				<bean class="org.springframework.jdbc.core.SqlParameter">
+					<constructor-arg index="0" value="country"/>
+					<constructor-arg index="1">
+						<util:constant static-field="java.sql.Types.VARCHAR"/>
+					</constructor-arg>
+				</bean>
+			</list>
+		</property>
+		<property name="rowMapper">
+			<bean class="org.springframework.jdbc.object.CustomerMapper"/>
+		</property>
+	</bean>
+
 </beans>
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