DATAJDBC-155 - Simplified construction of JdbcRepositoryFactory.

Made the DefaultDataAccessStrategy actually the default for JdbcRepositoryFactoryBean.
Therefore the injection of a strategy is optional.

Simplified constructors of DefaultDataAccessStrategy.
Created factory method to construct a correct DataAccessStrategy for use with MyBatis.

Did some untangling in the test application context configurations.

Original pull request: #54.

src/main/java/org/springframework/data/jdbc/core/DefaultDataAccessStrategy.java

@@ -56,11 +56,11 @@ public class DefaultDataAccessStrategy implements DataAccessStrategy {
 	private final JdbcMappingContext context;
 	private final DataAccessStrategy accessStrategy;
 
-	public DefaultDataAccessStrategy(SqlGeneratorSource sqlGeneratorSource, NamedParameterJdbcOperations operations,
-			JdbcMappingContext context, DataAccessStrategy accessStrategy) {
+	public DefaultDataAccessStrategy(SqlGeneratorSource sqlGeneratorSource, JdbcMappingContext context,
+			DataAccessStrategy accessStrategy) {
 
 		this.sqlGeneratorSource = sqlGeneratorSource;
-		this.operations = operations;
+		this.operations = context.getTemplate();
 		this.context = context;
 		this.accessStrategy = accessStrategy;
 	}
@@ -69,11 +69,10 @@ public class DefaultDataAccessStrategy implements DataAccessStrategy {
 	 * Creates a {@link DefaultDataAccessStrategy} which references it self for resolution of recursive data accesses.
 	 * Only suitable if this is the only access strategy in use.
 	 */
-	public DefaultDataAccessStrategy(SqlGeneratorSource sqlGeneratorSource, NamedParameterJdbcOperations operations,
-			JdbcMappingContext context) {
+	public DefaultDataAccessStrategy(SqlGeneratorSource sqlGeneratorSource, JdbcMappingContext context) {
 
 		this.sqlGeneratorSource = sqlGeneratorSource;
-		this.operations = operations;
+		this.operations = context.getTemplate();
 		this.context = context;
 		this.accessStrategy = this;
 	}

src/main/java/org/springframework/data/jdbc/mybatis/MyBatisDataAccessStrategy.java

@@ -15,15 +15,22 @@
  */
 package org.springframework.data.jdbc.mybatis;
 
-import org.apache.ibatis.session.SqlSession;
-import org.mybatis.spring.SqlSessionTemplate;
-import org.springframework.data.jdbc.core.DataAccessStrategy;
-import org.springframework.data.jdbc.mapping.model.JdbcPersistentProperty;
-import org.springframework.data.mapping.PropertyPath;
+import static java.util.Arrays.*;
 
 import java.util.Collections;
 import java.util.Map;
 
+import org.apache.ibatis.session.SqlSession;
+import org.mybatis.spring.SqlSessionTemplate;
+import org.springframework.data.jdbc.core.CascadingDataAccessStrategy;
+import org.springframework.data.jdbc.core.DataAccessStrategy;
+import org.springframework.data.jdbc.core.DefaultDataAccessStrategy;
+import org.springframework.data.jdbc.core.DelegatingDataAccessStrategy;
+import org.springframework.data.jdbc.core.SqlGeneratorSource;
+import org.springframework.data.jdbc.mapping.model.JdbcMappingContext;
+import org.springframework.data.jdbc.mapping.model.JdbcPersistentProperty;
+import org.springframework.data.mapping.PropertyPath;
+
 /**
  * {@link DataAccessStrategy} implementation based on MyBatis. Each method gets mapped to a statement. The name of the
  * statement gets constructed as follows: The namespace is based on the class of the entity plus the suffix "Mapper".
@@ -41,11 +48,43 @@ public class MyBatisDataAccessStrategy implements DataAccessStrategy {
 
 	private final SqlSession sqlSession;
 
+	/**
+	 * Create a {@link DataAccessStrategy} that first checks for queries defined by MyBatis and if it doesn't find one
+	 * used a {@link DefaultDataAccessStrategy}
+	 * 
+	 * @param context
+	 * @param sqlSession
+	 * @return
+	 */
+	public static DataAccessStrategy createCombinedAccessStrategy(JdbcMappingContext context, SqlSession sqlSession) {
+
+		// the DefaultDataAccessStrategy needs a reference to the returned DataAccessStrategy. This creates a dependency
+		// cycle. In order to create it, we need something that allows to defer closing the cycle until all the elements are
+		// created. That is the purpose of the DelegatingAccessStrategy.
+		DelegatingDataAccessStrategy delegatingDataAccessStrategy = new DelegatingDataAccessStrategy();
+		MyBatisDataAccessStrategy myBatisDataAccessStrategy = new MyBatisDataAccessStrategy(sqlSession);
+
+		CascadingDataAccessStrategy cascadingDataAccessStrategy = new CascadingDataAccessStrategy(
+				asList(myBatisDataAccessStrategy, delegatingDataAccessStrategy));
+
+		DefaultDataAccessStrategy defaultDataAccessStrategy = new DefaultDataAccessStrategy( //
+				new SqlGeneratorSource(context), //
+				context, //
+				cascadingDataAccessStrategy);
+
+		delegatingDataAccessStrategy.setDelegate(defaultDataAccessStrategy);
+
+		return cascadingDataAccessStrategy;
+	}
+
 	/**
 	 * Constructs a {@link DataAccessStrategy} based on MyBatis.
 	 * <p>
-	 * Use a {@link SqlSessionTemplate} for {@link SqlSession} or a similar implementation tying the session to the
-	 * proper transaction.
+	 * Use a {@link SqlSessionTemplate} for {@link SqlSession} or a similar implementation tying the session to the proper
+	 * transaction. Note that the resulting {@link DataAccessStrategy} only handles MyBatis. It does not include the
+	 * functionality of the {@link org.springframework.data.jdbc.core.DefaultDataAccessStrategy} which one normally still
+	 * wants. Use {@link #createCombinedAccessStrategy(JdbcMappingContext, SqlSession)} to create such a
+	 * {@link DataAccessStrategy}.
 	 *
 	 * @param sqlSession Must be non {@literal null}.
 	 */

src/main/java/org/springframework/data/jdbc/repository/config/JdbcConfiguration.java

@@ -22,18 +22,20 @@ import org.springframework.context.annotation.Configuration;
 import org.springframework.data.jdbc.mapping.model.ConversionCustomizer;
 import org.springframework.data.jdbc.mapping.model.JdbcMappingContext;
 import org.springframework.data.jdbc.mapping.model.NamingStrategy;
+import org.springframework.jdbc.core.namedparam.NamedParameterJdbcOperations;
 import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;
 
 /**
  * Beans that must be registered for Spring Data JDBC to work.
  *
  * @author Greg Turnquist
+ * @author Jens Schauder
  */
 @Configuration
 public class JdbcConfiguration {
 
 	@Bean
-	JdbcMappingContext jdbcMappingContext(NamedParameterJdbcTemplate template, Optional<NamingStrategy> namingStrategy,
+	JdbcMappingContext jdbcMappingContext(NamedParameterJdbcOperations template, Optional<NamingStrategy> namingStrategy,
 			Optional<ConversionCustomizer> conversionCustomizer) {
 
 		return new JdbcMappingContext(namingStrategy.orElse(NamingStrategy.INSTANCE), template,

src/main/java/org/springframework/data/jdbc/repository/support/JdbcRepositoryFactoryBean.java

@@ -21,6 +21,8 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.context.ApplicationEventPublisherAware;
 import org.springframework.data.jdbc.core.DataAccessStrategy;
+import org.springframework.data.jdbc.core.DefaultDataAccessStrategy;
+import org.springframework.data.jdbc.core.SqlGeneratorSource;
 import org.springframework.data.jdbc.mapping.model.JdbcMappingContext;
 import org.springframework.data.jdbc.repository.RowMapperMap;
 import org.springframework.data.repository.Repository;
@@ -80,7 +82,7 @@ public class JdbcRepositoryFactoryBean<T extends Repository<S, ID>, S, ID extend
 		this.mappingContext = mappingContext;
 	}
 
-	@Autowired
+	@Autowired(required = false)
 	public void setDataAccessStrategy(DataAccessStrategy dataAccessStrategy) {
 		this.dataAccessStrategy = dataAccessStrategy;
 	}
@@ -93,8 +95,15 @@ public class JdbcRepositoryFactoryBean<T extends Repository<S, ID>, S, ID extend
 	@Override
 	public void afterPropertiesSet() {
 
-		Assert.notNull(this.dataAccessStrategy, "DataAccessStrategy must not be null!");
 		Assert.notNull(this.mappingContext, "MappingContext must not be null!");
+
+		if (dataAccessStrategy == null) {
+
+			dataAccessStrategy = new DefaultDataAccessStrategy( //
+					new SqlGeneratorSource(mappingContext), //
+					mappingContext);
+		}
+
 		super.afterPropertiesSet();
 	}
 }