DATAJPA-12 - Added Sort implementations for JPA meta-model API and Querydsl.

Introduced JpaSort for sorting by JPA meta-model attribute paths. Introduced JpaMetaModelPathBuilder that can be used to ease the construction of Jpa meta-model attribute paths by the provided static factory method. Added new testing scenario (MailMessage and MailSender) to avoid to mess up the existing sample classes. Enabled static JPA meta-model generation in pom.xml.

Enhanced Querydsl to generate appropriate left joins when sorting by nested (singular) association properties. Converted XML configuration for QueryDslRepositorySupportIntegrationTests into JavaConfig.

Original pull request: #54.

src/test/java/org/springframework/data/jpa/domain/JpaSortTests.java

@@ -0,0 +1,188 @@
+/*
+ * Copyright 2013 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.jpa.domain;
+
+import static org.hamcrest.CoreMatchers.*;
+import static org.junit.Assert.*;
+import static org.springframework.data.jpa.support.JpaMetaModelPathBuilder.*;
+
+import java.util.List;
+
+import javax.persistence.EntityManager;
+import javax.persistence.PersistenceContext;
+import javax.persistence.criteria.CriteriaBuilder;
+import javax.persistence.criteria.CriteriaQuery;
+import javax.persistence.criteria.Path;
+import javax.persistence.criteria.Root;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.ImportResource;
+import org.springframework.data.domain.Sort;
+import org.springframework.data.domain.Sort.Direction;
+import org.springframework.data.jpa.domain.sample.MailMessage_;
+import org.springframework.data.jpa.domain.sample.MailSender_;
+import org.springframework.data.jpa.domain.sample.User;
+import org.springframework.data.jpa.domain.sample.User_;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+/**
+ * Unit test for {@link JpaSort}.
+ * 
+ * @author Thomas Darimont
+ */
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration
+public class JpaSortTests {
+
+	@Configuration
+	@ImportResource("classpath:infrastructure.xml")
+	static class Config {}
+
+	@PersistenceContext EntityManager em;
+
+	private static final MailMessage_ jmail = null;
+	private static final MailSender_ jsender = null;
+
+	/**
+	 * @see DATAJPA-12
+	 */
+	@Test(expected = IllegalArgumentException.class)
+	public void shouldThrowIfNoOrderSpecifiersAreGiven() {
+		new JpaSort();
+	}
+
+	/**
+	 * @see DATAJPA-12
+	 */
+	@Test(expected = IllegalArgumentException.class)
+	public void shouldThrowIfNullIsGiven() {
+		new JpaSort((List<Path<?>>) null);
+	}
+
+	/**
+	 * @see DATAJPA-12
+	 */
+	@Test
+	public void sortBySinglePropertyWithDefaultSortDirection() {
+
+		CriteriaBuilder cb = em.getCriteriaBuilder();
+		CriteriaQuery<User> q = cb.createQuery(User.class);
+		Root<User> c = q.from(User.class);
+
+		JpaSort sort = new JpaSort(c.get("firstname"));
+
+		assertThat(sort, hasItems(new Sort.Order("firstname")));
+	}
+
+	/**
+	 * @see DATAJPA-12
+	 */
+	@Test
+	public void sortByMultiplePropertiesWithDefaultSortDirection() {
+
+		CriteriaBuilder cb = em.getCriteriaBuilder();
+		CriteriaQuery<User> q = cb.createQuery(User.class);
+		Root<User> c = q.from(User.class);
+
+		JpaSort sort = new JpaSort(c.get("firstname"), c.get("lastname"));
+		assertThat(sort, hasItems(new Sort.Order("firstname"), new Sort.Order("lastname")));
+	}
+
+	/**
+	 * @see DATAJPA-12
+	 */
+	@Test
+	public void sortByMultiplePropertiesWithDescSortDirection() {
+
+		CriteriaBuilder cb = em.getCriteriaBuilder();
+		CriteriaQuery<User> q = cb.createQuery(User.class);
+		Root<User> c = q.from(User.class);
+
+		JpaSort sort = new JpaSort(Direction.DESC, c.get("firstname"), c.get("lastname"));
+
+		assertThat(sort, hasItems(new Sort.Order(Direction.DESC, "firstname"), new Sort.Order(Direction.DESC, "lastname")));
+	}
+
+	/**
+	 * @see DATAJPA-12
+	 */
+	@Test
+	public void combiningSortByMultipleProperties() {
+
+		CriteriaBuilder cb = em.getCriteriaBuilder();
+		CriteriaQuery<User> q = cb.createQuery(User.class);
+		Root<User> c = q.from(User.class);
+
+		Sort sort = new JpaSort(c.get("firstname")).and(new JpaSort(c.get("lastname")));
+
+		assertThat(sort, hasItems(new Sort.Order("firstname"), new Sort.Order("lastname")));
+	}
+
+	/**
+	 * @see DATAJPA-12
+	 */
+	@Test
+	public void combiningSortByMultiplePropertiesWithDifferentSort() {
+
+		CriteriaBuilder cb = em.getCriteriaBuilder();
+		CriteriaQuery<User> q = cb.createQuery(User.class);
+		Root<User> c = q.from(User.class);
+
+		Sort sort = new JpaSort(c.get("firstname")).and(new JpaSort(Direction.DESC, c.get("lastname")));
+
+		assertThat(sort, hasItems(new Sort.Order("firstname"), new Sort.Order(Direction.DESC, "lastname")));
+	}
+
+	/**
+	 * @see DATAJPA-12
+	 */
+	@Test
+	public void combiningSortByNestedEmbeddedProperty() {
+
+		CriteriaBuilder cb = em.getCriteriaBuilder();
+		CriteriaQuery<User> q = cb.createQuery(User.class);
+		Root<User> c = q.from(User.class);
+
+		Sort sort = new JpaSort(c.get("address").get("streetName"));
+
+		assertThat(sort, hasItems(new Sort.Order("address.streetName")));
+	}
+
+	/**
+	 * @see DATAJPA-12
+	 */
+	@Test
+	public void buildJpaSortFromJpaMetaModelSingleAttribute() {
+
+		Sort sort = new JpaSort(Direction.ASC, path(User_.firstname).build(em));
+
+		assertThat(sort, hasItems(new Sort.Order("firstname")));
+	}
+
+	/**
+	 * @see DATAJPA-12
+	 */
+	@Test
+	public void buildJpaSortFromJpaMetaModelNestedAttribute() {
+
+		Sort sort = new JpaSort(Direction.ASC, path(MailMessage_.mailSender).get(MailSender_.name).build(em));
+
+		assertThat(sort, hasItems(new Sort.Order("mailSender.name")));
+	}
+}

src/test/java/org/springframework/data/jpa/domain/sample/MailMessage.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright 2013 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.jpa.domain.sample;
+
+import javax.persistence.CascadeType;
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.OneToOne;
+
+/**
+ * @author Thomas Darimont
+ */
+@Entity
+public class MailMessage {
+
+	@Id @GeneratedValue private Long id;
+
+	@OneToOne(cascade = CascadeType.ALL) private MailSender mailSender;
+
+	private String content;
+
+	public MailSender getMailSender() {
+		return mailSender;
+	}
+
+	public void setMailSender(MailSender sender) {
+		this.mailSender = sender;
+	}
+
+	public String getContent() {
+		return content;
+	}
+
+	public void setContent(String content) {
+		this.content = content;
+	}
+
+	public Long getId() {
+		return id;
+	}
+
+	public void setId(Long id) {
+		this.id = id;
+	}
+}

src/test/java/org/springframework/data/jpa/domain/sample/MailSender.java

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2013 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.jpa.domain.sample;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+
+/**
+ * @author Thomas Darimont
+ */
+@Entity
+public class MailSender {
+
+	@Id @GeneratedValue private Long id;
+
+	private String name;
+
+	public MailSender() {}
+
+	public MailSender(String name) {
+		this.name = name;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	public Long getId() {
+		return id;
+	}
+
+	public void setId(Long id) {
+		this.id = id;
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see java.lang.Object#hashCode()
+	 */
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		result = prime * result + ((name == null) ? 0 : name.hashCode());
+		return result;
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see java.lang.Object#equals(java.lang.Object)
+	 */
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (obj == null)
+			return false;
+		if (getClass() != obj.getClass())
+			return false;
+		MailSender other = (MailSender) obj;
+		if (name == null) {
+			if (other.name != null)
+				return false;
+		} else if (!name.equals(other.name))
+			return false;
+		return true;
+	}
+}

src/test/java/org/springframework/data/jpa/domain/sample/User.java

@@ -64,10 +64,7 @@ public class User {
 	 * Creates a new empty instance of {@code User}.
 	 */
 	public User() {
-
-		this.roles = new HashSet<Role>();
-		this.colleagues = new HashSet<User>();
-		this.createdAt = new Date();
+		this(null, null, null);
 	}
 
 	/**
@@ -77,13 +74,15 @@ public class User {
 	 * @param lastname
 	 * @param emailAddress
 	 */
-	public User(final String firstname, final String lastname, final String emailAddress) {
+	public User(String firstname, String lastname, String emailAddress) {
 
-		this();
 		this.firstname = firstname;
 		this.lastname = lastname;
 		this.emailAddress = emailAddress;
 		this.active = true;
+		this.roles = new HashSet<Role>();
+		this.colleagues = new HashSet<User>();
+		this.createdAt = new Date();
 	}
 
 	/**

src/test/java/org/springframework/data/jpa/repository/config/InfrastructureConfig.java

@@ -35,7 +35,7 @@ import org.springframework.transaction.annotation.EnableTransactionManagement;
  */
 @Configuration
 @EnableTransactionManagement
-class InfrastructureConfig {
+public class InfrastructureConfig {
 
 	@Bean
 	public DataSource dataSource() {

src/test/java/org/springframework/data/jpa/repository/sample/MailMessageRepository.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2013 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.jpa.repository.sample;
+
+import java.util.List;
+
+import org.springframework.data.jpa.domain.sample.MailMessage;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.querydsl.QueryDslPredicateExecutor;
+
+import com.mysema.query.types.OrderSpecifier;
+import com.mysema.query.types.Predicate;
+
+/**
+ * @author Thomas Darimont
+ */
+public interface MailMessageRepository extends JpaRepository<MailMessage, Long>, QueryDslPredicateExecutor<MailMessage> {
+
+	List<MailMessage> findAll(Predicate predicate, OrderSpecifier<?>... orders);
+}

src/test/java/org/springframework/data/jpa/repository/support/JpaMetaModelRepositoryUnitTests.java

@@ -0,0 +1,92 @@
+/*
+ * Copyright 2013 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.jpa.repository.support;
+
+import static org.hamcrest.Matchers.*;
+import static org.junit.Assert.*;
+import static org.springframework.data.jpa.support.JpaMetaModelPathBuilder.*;
+
+import java.util.List;
+
+import javax.persistence.EntityManager;
+import javax.persistence.PersistenceContext;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.PageRequest;
+import org.springframework.data.domain.Sort.Direction;
+import org.springframework.data.jpa.domain.JpaSort;
+import org.springframework.data.jpa.domain.sample.MailMessage;
+import org.springframework.data.jpa.domain.sample.MailMessage_;
+import org.springframework.data.jpa.domain.sample.MailSender;
+import org.springframework.data.jpa.domain.sample.MailSender_;
+import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
+import org.springframework.data.jpa.repository.config.InfrastructureConfig;
+import org.springframework.data.jpa.repository.sample.MailMessageRepository;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.transaction.annotation.Transactional;
+
+/**
+ * @author Thomas Darimont
+ */
+@Transactional
+@ContextConfiguration
+@RunWith(SpringJUnit4ClassRunner.class)
+public class JpaMetaModelRepositoryUnitTests {
+
+	@Configuration
+	@Import(InfrastructureConfig.class)
+	@EnableJpaRepositories(basePackageClasses = MailMessageRepository.class)
+	static class Config {}
+
+	private static final MailMessage_ jmail = null;
+	private static final MailSender_ jsender = null;
+
+	@PersistenceContext EntityManager em;
+
+	@Autowired MailMessageRepository mailMessageRepository;
+
+	/**
+	 * @see DATAJPA-12
+	 */
+	@Test
+	public void shouldSortMailWithPageRequestAndJpaSortCriteriaNullsFirst() {
+
+		MailMessage message1 = new MailMessage();
+		message1.setContent("abc");
+		MailSender sender1 = new MailSender("foo");
+		message1.setMailSender(sender1);
+
+		MailMessage message2 = new MailMessage();
+		message2.setContent("abc");
+
+		mailMessageRepository.save(message1);
+		mailMessageRepository.save(message2);
+
+		Page<MailMessage> results = mailMessageRepository.findAll(new PageRequest(0, 20, //
+				new JpaSort(Direction.ASC, path(jmail.mailSender).get(jsender.name).build(em))));
+		List<MailMessage> messages = results.getContent();
+
+		assertThat(messages, hasSize(2));
+		assertThat(messages.get(0).getMailSender(), is(nullValue()));
+		assertThat(messages.get(1).getMailSender(), is(sender1));
+	}
+}

src/test/java/org/springframework/data/jpa/repository/support/QueryDslJpaRepositoryTests.java

@@ -34,6 +34,8 @@ import org.springframework.data.domain.Sort.Order;
 import org.springframework.data.jpa.domain.sample.Address;
 import org.springframework.data.jpa.domain.sample.QUser;
 import org.springframework.data.jpa.domain.sample.User;
+import org.springframework.data.querydsl.QPageRequest;
+import org.springframework.data.querydsl.QSort;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 import org.springframework.transaction.annotation.Transactional;
@@ -215,4 +217,60 @@ public class QueryDslJpaRepositoryTests {
 		assertThat(page.getContent(), hasItems(dave, carter, oliver));
 		assertThat(page.getContent().get(2), is(oliver));
 	}
+
+	/**
+	 * @see DATAJPA-12
+	 */
+	@Test
+	public void findBySpecificationWithSortByQueryDslOrderSpecifierWithQPageRequestAndQSort() {
+
+		QUser user = QUser.user;
+
+		Page<User> page = repository.findAll(user.firstname.isNotNull(),
+				new QPageRequest(0, 10, new QSort(user.firstname.asc())));
+
+		assertThat(page.getContent(), hasSize(3));
+		assertThat(page.getContent(), hasItems(carter, dave, oliver));
+		assertThat(page.getContent().get(0), is(carter));
+		assertThat(page.getContent().get(1), is(dave));
+		assertThat(page.getContent().get(2), is(oliver));
+	}
+
+	/**
+	 * @see DATAJPA-12
+	 */
+	@Test
+	public void findBySpecificationWithSortByQueryDslOrderSpecifierWithQPageRequest() {
+
+		QUser user = QUser.user;
+
+		Page<User> page = repository.findAll(user.firstname.isNotNull(), new QPageRequest(0, 10, user.firstname.asc()));
+
+		assertThat(page.getContent(), hasSize(3));
+		assertThat(page.getContent(), hasItems(carter, dave, oliver));
+		assertThat(page.getContent().get(0), is(carter));
+		assertThat(page.getContent().get(1), is(dave));
+		assertThat(page.getContent().get(2), is(oliver));
+	}
+
+	/**
+	 * @see DATAJPA-12
+	 */
+	@Test
+	public void findBySpecificationWithSortByQueryDslOrderSpecifierForAssociationShouldGenerateLeftJoinWithQPageRequest() {
+
+		oliver.setManager(dave);
+		dave.setManager(carter);
+
+		QUser user = QUser.user;
+
+		Page<User> page = repository.findAll(user.firstname.isNotNull(),
+				new QPageRequest(0, 10, user.manager.firstname.asc()));
+
+		assertThat(page.getContent(), hasSize(3));
+		assertThat(page.getContent(), hasItems(carter, dave, oliver));
+		assertThat(page.getContent().get(0), is(carter));
+		assertThat(page.getContent().get(1), is(dave));
+		assertThat(page.getContent().get(2), is(oliver));
+	}
 }

src/test/java/org/springframework/data/jpa/repository/support/QueryDslRepositorySupportIntegrationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011 the original author or authors.
+ * Copyright 2011-2013 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.
@@ -15,37 +15,96 @@
  */
 package org.springframework.data.jpa.repository.support;
 
-import static org.hamcrest.CoreMatchers.*;
+import static org.hamcrest.Matchers.*;
 import static org.junit.Assert.*;
 
+import java.util.List;
+
 import javax.persistence.EntityManager;
 import javax.persistence.PersistenceContext;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.ComponentScan.Filter;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.FilterType;
+import org.springframework.data.domain.Page;
+import org.springframework.data.jpa.domain.sample.MailMessage;
+import org.springframework.data.jpa.domain.sample.MailSender;
+import org.springframework.data.jpa.domain.sample.QMailMessage;
+import org.springframework.data.jpa.domain.sample.QMailSender;
 import org.springframework.data.jpa.domain.sample.User;
+import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
+import org.springframework.data.jpa.repository.config.InfrastructureConfig;
+import org.springframework.data.jpa.repository.sample.MailMessageRepository;
 import org.springframework.data.jpa.repository.support.QueryDslRepositorySupportTests.UserRepository;
+import org.springframework.data.jpa.repository.support.QueryDslRepositorySupportTests.UserRepositoryImpl;
+import org.springframework.data.querydsl.QPageRequest;
+import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.transaction.annotation.EnableTransactionManagement;
+import org.springframework.transaction.annotation.Transactional;
 
 /**
  * Integration test for the setup of beans extending {@link QueryDslRepositorySupport}.
  * 
  * @author Oliver Gierke
+ * @author Thomas Darimont
  */
+@Transactional
+@ContextConfiguration
 @RunWith(SpringJUnit4ClassRunner.class)
-@ContextConfiguration("classpath:querydsl.xml")
 public class QueryDslRepositorySupportIntegrationTests {
 
-	@Autowired
-	UserRepository repository;
+	@Configuration
+	@EnableJpaRepositories(basePackageClasses = MailMessageRepository.class, includeFilters = @Filter(
+			type = FilterType.ASSIGNABLE_TYPE, value = { MailMessageRepository.class }))
+	@EnableTransactionManagement
+	static class Config extends InfrastructureConfig {
+		@Bean
+		public UserRepositoryImpl userRepositoryImpl() {
 
-	@Autowired
-	ReconfiguringUserRepositoryImpl reconfiguredRepo;
+			return new UserRepositoryImpl() {
+				@Override
+				@PersistenceContext(unitName = "querydsl")
+				public void setEntityManager(EntityManager entityManager) {
+					super.setEntityManager(entityManager);
+				}
+			};
+		}
 
-	@PersistenceContext(unitName = "querydsl")
-	EntityManager em;
+		@Bean
+		public ReconfiguringUserRepositoryImpl reconfiguringUserRepositoryImpl() {
+			return new ReconfiguringUserRepositoryImpl();
+		}
+
+		@Bean
+		public EntityManagerContainer entityManagerContainer() {
+			return new EntityManagerContainer();
+		}
+
+		@Bean
+		public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
+
+			LocalContainerEntityManagerFactoryBean emf = super.entityManagerFactory();
+			emf.setPersistenceUnitName("querydsl");
+			return emf;
+		}
+	}
+
+	@Autowired UserRepository repository;
+
+	@Autowired ReconfiguringUserRepositoryImpl reconfiguredRepo;
+
+	@Autowired MailMessageRepository mailMessageRepository;
+
+	@PersistenceContext(unitName = "querydsl") EntityManager em;
+
+	static final QMailMessage qmail = QMailMessage.mailMessage;
+	static final QMailSender qsender = QMailSender.mailSender;
 
 	@Test
 	public void createsRepoCorrectly() {
@@ -62,6 +121,56 @@ public class QueryDslRepositorySupportIntegrationTests {
 		assertThat(reconfiguredRepo.getEntityManager().getEntityManagerFactory(), is(em.getEntityManagerFactory()));
 	}
 
+	/**
+	 * @see DATAJPA-12
+	 */
+	@Test
+	public void shouldSortMailWithQueryDslRepositoryAndQPageRequestDslSortCriteriaNullsFirst() {
+
+		MailMessage message1 = new MailMessage();
+		message1.setContent("abc");
+		MailSender sender1 = new MailSender("foo");
+		message1.setMailSender(sender1);
+
+		MailMessage message2 = new MailMessage();
+		message2.setContent("abc");
+
+		mailMessageRepository.save(message1);
+		mailMessageRepository.save(message2);
+
+		Page<MailMessage> results = mailMessageRepository.findAll(qmail.content.eq("abc"), new QPageRequest(0, 20,
+				qsender.name.asc()));
+		List<MailMessage> messages = results.getContent();
+
+		assertThat(messages, hasSize(2));
+		assertThat(messages.get(0).getMailSender(), is(nullValue()));
+		assertThat(messages.get(1).getMailSender(), is(sender1));
+	}
+
+	/**
+	 * @see DATAJPA-12
+	 */
+	@Test
+	public void shouldSortMailWithQueryDslRepositoryAndDslSortCriteriaNullsFirst() {
+
+		MailMessage message1 = new MailMessage();
+		message1.setContent("abc");
+		MailSender sender1 = new MailSender("foo");
+		message1.setMailSender(sender1);
+
+		MailMessage message2 = new MailMessage();
+		message2.setContent("abc");
+
+		mailMessageRepository.save(message1);
+		mailMessageRepository.save(message2);
+
+		List<MailMessage> messages = mailMessageRepository.findAll(qmail.content.eq("abc"), qmail.mailSender.name.asc());
+
+		assertThat(messages, hasSize(2));
+		assertThat(messages.get(0).getMailSender(), is(nullValue()));
+		assertThat(messages.get(1).getMailSender(), is(sender1));
+	}
+
 	static class ReconfiguringUserRepositoryImpl extends QueryDslRepositorySupport {
 
 		public ReconfiguringUserRepositoryImpl() {
@@ -77,7 +186,6 @@ public class QueryDslRepositorySupportIntegrationTests {
 
 	static class EntityManagerContainer {
 
-		@PersistenceContext(unitName = "querydsl")
-		EntityManager em;
+		@PersistenceContext(unitName = "querydsl") EntityManager em;
 	}
 }

src/test/java/org/springframework/data/jpa/repository/support/QueryDslRepositorySupportTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011 the original author or authors.
+ * Copyright 2011-2013 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.
@@ -36,14 +36,14 @@ import org.springframework.transaction.annotation.Transactional;
  * Integration test for {@link QueryDslRepositorySupport}.
  * 
  * @author Oliver Gierke
+ * @author Thomas Darimont
  */
 @RunWith(SpringJUnit4ClassRunner.class)
 @ContextConfiguration({ "classpath:infrastructure.xml" })
 @Transactional
 public class QueryDslRepositorySupportTests {
 
-	@PersistenceContext
-	EntityManager em;
+	@PersistenceContext EntityManager em;
 
 	UserRepository repository;
 	User dave, carter;