#81 - Samples for new projection support for JPA and MongoDB.

jpa/example/src/main/java/example/springdata/jpa/projections/Customer.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2015 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 example.springdata.jpa.projections;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+
+import lombok.Data;
+import lombok.RequiredArgsConstructor;
+
+/**
+ * @author Oliver Gierke
+ */
+@Data
+@Entity
+@RequiredArgsConstructor
+public class Customer {
+
+	private @GeneratedValue @Id Long id;
+	private final String firstname, lastname;
+
+	protected Customer() {
+		this.firstname = null;
+		this.lastname = null;
+	}
+}

jpa/example/src/main/java/example/springdata/jpa/projections/CustomerDto.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2015 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 example.springdata.jpa.projections;
+
+import lombok.Data;
+import lombok.RequiredArgsConstructor;
+
+/**
+ * @author Oliver Gierke
+ */
+@Data
+@RequiredArgsConstructor
+public class CustomerDto {
+
+	private final String firstname;
+}

jpa/example/src/main/java/example/springdata/jpa/projections/CustomerProjection.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2015 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 example.springdata.jpa.projections;
+
+/**
+ *
+ * @author Oliver Gierke
+ */
+public interface CustomerProjection {
+
+	String getFirstname();
+}

jpa/example/src/main/java/example/springdata/jpa/projections/CustomerRepository.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright 2015 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 example.springdata.jpa.projections;
+
+import java.util.Collection;
+
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.CrudRepository;
+
+/**
+ * @author Oliver Gierke
+ */
+public interface CustomerRepository extends CrudRepository<Customer, Long> {
+
+	/**
+	 * Uses a projection interface to indicate the fields to be returned. As the projection doesn't use any dynamic
+	 * fields, the query execution will be restricted to only the fields needed by the projection.
+	 * 
+	 * @return
+	 */
+	Collection<CustomerProjection> findAllProjectedBy();
+
+	/**
+	 * When a projection is used that contains dynamic properties (i.e. SpEL expressions in an {@link Value} annotation),
+	 * the normal target entity will be loaded but dynamically projected so that the target can be referred to in the
+	 * expression.
+	 * 
+	 * @return
+	 */
+	Collection<CustomerSummary> findAllSummarizedBy();
+
+	/**
+	 * Projection interfaces can be used with manually declared queries, too. Make sure you alias the projects matching
+	 * the projection fields.
+	 * 
+	 * @return
+	 */
+	@Query("select c.firstname as firstname, c.lastname as lastname from Customer c")
+	Collection<CustomerProjection> findsByProjectedColumns();
+
+	/**
+	 * Uses a concrete DTO type to indicate the fields to be returned. This gets translated into a constructor expression
+	 * in the query.
+	 * 
+	 * @return
+	 */
+	Collection<CustomerDto> findAllDtoedBy();
+
+	/**
+	 * Passes in the projection type dynamically (either interface or DTO).
+	 * 
+	 * @param firstname
+	 * @param projection
+	 * @return
+	 */
+	<T> Collection<T> findByFirstname(String firstname, Class<T> projection);
+
+	/**
+	 * Projection for a single entity.
+	 * 
+	 * @param id
+	 * @return
+	 */
+	CustomerProjection findProjectedById(Long id);
+
+	/**
+	 * Dynamic projection for a single entity.
+	 * 
+	 * @param id
+	 * @param projection
+	 * @return
+	 */
+	<T> T findProjectedById(Long id, Class<T> projection);
+}

jpa/example/src/main/java/example/springdata/jpa/projections/CustomerSummary.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2015 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 example.springdata.jpa.projections;
+
+import org.springframework.beans.factory.annotation.Value;
+
+/**
+ * @author Oliver Gierke
+ */
+public interface CustomerSummary {
+
+	@Value("#{target.firstname + ' ' + target.lastname}")
+	String getFullName();
+}

jpa/example/src/test/java/example/springdata/jpa/projections/CustomerRepositoryIntegrationTest.java

@@ -0,0 +1,115 @@
+/*
+ * Copyright 2015 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 example.springdata.jpa.projections;
+
+import static org.hamcrest.Matchers.*;
+import static org.junit.Assert.*;
+
+import java.util.Collection;
+import java.util.Map;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.data.projection.TargetAware;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.transaction.annotation.Transactional;
+
+/**
+ * Integaration tests for {@link CustomerRepository} to show projection capabilities.
+ * 
+ * @author Oliver Gierke
+ */
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration
+@Transactional
+public class CustomerRepositoryIntegrationTest {
+
+	@Configuration
+	@EnableAutoConfiguration
+	static class Config {}
+
+	@Autowired CustomerRepository customers;
+
+	Customer dave, carter;
+
+	@Before
+	public void setUp() {
+
+		this.dave = customers.save(new Customer("Dave", "Matthews"));
+		this.carter = customers.save(new Customer("Carter", "Beauford"));
+	}
+
+	@Test
+	public void projectsEntityIntoInterface() {
+
+		Collection<CustomerProjection> result = customers.findAllProjectedBy();
+
+		assertThat(result, hasSize(2));
+		assertThat(result.iterator().next().getFirstname(), is("Dave"));
+	}
+
+	@Test
+	public void projectsMapIntoInterface() {
+
+		Collection<CustomerProjection> result = customers.findsByProjectedColumns();
+
+		assertThat(result, hasSize(2));
+		assertThat(result.iterator().next().getFirstname(), is("Dave"));
+	}
+
+	@Test
+	public void projectsToDto() {
+
+		Collection<CustomerDto> result = customers.findAllDtoedBy();
+
+		assertThat(result, hasSize(2));
+		assertThat(result.iterator().next().getFirstname(), is("Dave"));
+	}
+
+	@Test
+	public void projectsDynamically() {
+
+		Collection<CustomerProjection> result = customers.findByFirstname("Dave", CustomerProjection.class);
+
+		assertThat(result, hasSize(1));
+		assertThat(result.iterator().next().getFirstname(), is("Dave"));
+	}
+
+	@Test
+	public void projectsIndividualDynamically() {
+
+		CustomerSummary result = customers.findProjectedById(dave.getId(), CustomerSummary.class);
+
+		assertThat(result.getFullName(), is("Dave Matthews"));
+
+		// Proxy backed by original instance as the projection uses dynamic elements
+		assertThat(((TargetAware) result).getTarget(), is(instanceOf(Customer.class)));
+	}
+
+	@Test
+	public void projectIndividualInstance() {
+
+		CustomerProjection projectedDave = customers.findProjectedById(dave.getId());
+
+		assertThat(projectedDave.getFirstname(), is("Dave"));
+		assertThat(((TargetAware) projectedDave).getTarget(), is(instanceOf(Map.class)));
+	}
+}

mongodb/example/pom.xml

@@ -20,7 +20,7 @@
 				<version>${apt.version}</version>
 				<dependencies>
 					<dependency>
-						<groupId>com.mysema.querydsl</groupId>
+						<groupId>com.querydsl</groupId>
 						<artifactId>querydsl-apt</artifactId>
 						<version>${querydsl.version}</version>
 					</dependency>

mongodb/example/src/main/java/example/springdata/mongodb/projections/Customer.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2015-2016 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.
+ * 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 example.springdata.mongodb.projections;
+
+import lombok.Value;
+
+import org.bson.types.ObjectId;
+import org.springframework.data.annotation.Id;
+import org.springframework.data.mongodb.core.mapping.Document;
+
+/**
+ * @author Oliver Gierke
+ */
+@Value
+@Document
+class Customer {
+
+	@Id ObjectId id = new ObjectId();
+	String firstname, lastname;
+}

mongodb/example/src/main/java/example/springdata/mongodb/projections/CustomerDto.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2015-2016 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.
+ * 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 example.springdata.mongodb.projections;
+
+import lombok.Value;
+
+/**
+ * A sample DTO only containing the firstname.
+ * 
+ * @author Oliver Gierke
+ */
+@Value
+class CustomerDto {
+
+	String firstname;
+}

mongodb/example/src/main/java/example/springdata/mongodb/projections/CustomerProjection.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2015-2016 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.
+ * 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 example.springdata.mongodb.projections;
+
+/**
+ * An example projection interface containing only the firstname.
+ *
+ * @author Oliver Gierke
+ */
+interface CustomerProjection {
+
+	String getFirstname();
+}

mongodb/example/src/main/java/example/springdata/mongodb/projections/CustomerRepository.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2015-2016 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.
+ * 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 example.springdata.mongodb.projections;
+
+import java.util.Collection;
+
+import org.bson.types.ObjectId;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.data.repository.CrudRepository;
+
+/**
+ * Sample repository managing customers to show projecting functionality of Spring Data MongoDB.
+ * 
+ * @author Oliver Gierke
+ */
+interface CustomerRepository extends CrudRepository<Customer, ObjectId> {
+
+	/**
+	 * Uses a projection interface to indicate the fields to be returned. As the projection doesn't use any dynamic
+	 * fields, the query execution will be restricted to only the fields needed by the projection.
+	 * 
+	 * @return
+	 */
+	Collection<CustomerProjection> findAllProjectedBy();
+
+	/**
+	 * When a projection is used that contains dynamic properties (i.e. SpEL expressions in an {@link Value} annotation),
+	 * the normal target entity will be loaded but dynamically projected so that the target can be referred to in the
+	 * expression.
+	 * 
+	 * @return
+	 */
+	Collection<CustomerSummary> findAllSummarizedBy();
+
+	/**
+	 * Uses a concrete DTO type to indicate the fields to be returned. This will cause the original object being loaded
+	 * and the properties copied over into the DTO.
+	 * 
+	 * @return
+	 */
+	Collection<CustomerDto> findAllDtoedBy();
+
+	/**
+	 * Passes in the projection type dynamically (either interface or DTO).
+	 * 
+	 * @param firstname
+	 * @param projection
+	 * @return
+	 */
+	<T> Collection<T> findByFirstname(String firstname, Class<T> projection);
+
+	/**
+	 * Projection for a single entity.
+	 * 
+	 * @param id
+	 * @return
+	 */
+	CustomerProjection findProjectedById(ObjectId id);
+
+	/**
+	 * Dynamic projection for a single entity.
+	 * 
+	 * @param id
+	 * @param projection
+	 * @return
+	 */
+	<T> T findProjectedById(ObjectId id, Class<T> projection);
+}

mongodb/example/src/main/java/example/springdata/mongodb/projections/CustomerSummary.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2015-2016 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.
+ * 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 example.springdata.mongodb.projections;
+
+import org.springframework.beans.factory.annotation.Value;
+
+/**
+ * @author Oliver Gierke
+ */
+interface CustomerSummary {
+
+	@Value("#{target.firstname + ' ' + target.lastname}")
+	String getFullName();
+}

mongodb/example/src/test/java/example/springdata/mongodb/projections/CustomerRepositoryIntegrationTest.java

@@ -0,0 +1,109 @@
+/*
+ * Copyright 2015-2016 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.
+ * 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 example.springdata.mongodb.projections;
+
+import static org.hamcrest.Matchers.*;
+import static org.junit.Assert.*;
+
+import java.util.Collection;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.test.SpringApplicationConfiguration;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.data.projection.TargetAware;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.transaction.annotation.Transactional;
+
+/**
+ * Integration tests for {@link CustomerRepository} to show projection capabilities.
+ * 
+ * @author Oliver Gierke
+ */
+@RunWith(SpringJUnit4ClassRunner.class)
+@SpringApplicationConfiguration
+@Transactional
+public class CustomerRepositoryIntegrationTest {
+
+	@Configuration
+	@EnableAutoConfiguration
+	static class Config {}
+
+	@Autowired CustomerRepository customers;
+
+	Customer dave, carter;
+
+	@Before
+	public void setUp() {
+
+		customers.deleteAll();
+
+		this.dave = customers.save(new Customer("Dave", "Matthews"));
+		this.carter = customers.save(new Customer("Carter", "Beauford"));
+	}
+
+	@Test
+	public void projectsEntityIntoInterface() {
+
+		Collection<CustomerProjection> result = customers.findAllProjectedBy();
+
+		assertThat(result, hasSize(2));
+		assertThat(result.iterator().next().getFirstname(), is("Dave"));
+	}
+
+	@Test
+	public void projectsToDto() {
+
+		Collection<CustomerDto> result = customers.findAllDtoedBy();
+
+		assertThat(result, hasSize(2));
+		assertThat(result.iterator().next().getFirstname(), is("Dave"));
+	}
+
+	@Test
+	public void projectsDynamically() {
+
+		Collection<CustomerProjection> result = customers.findByFirstname("Dave", CustomerProjection.class);
+
+		assertThat(result, hasSize(1));
+		assertThat(result.iterator().next().getFirstname(), is("Dave"));
+	}
+
+	@Test
+	public void projectsIndividualDynamically() {
+
+		CustomerSummary result = customers.findProjectedById(dave.getId(), CustomerSummary.class);
+
+		assertThat(result, is(notNullValue()));
+		assertThat(result.getFullName(), is("Dave Matthews"));
+
+		// Proxy backed by original instance as the projection uses dynamic elements
+		assertThat(((TargetAware) result).getTarget(), is(instanceOf(Customer.class)));
+	}
+
+	@Test
+	public void projectIndividualInstance() {
+
+		CustomerProjection result = customers.findProjectedById(dave.getId());
+
+		assertThat(result, is(notNullValue()));
+		assertThat(result.getFirstname(), is("Dave"));
+		assertThat(((TargetAware) result).getTarget(), is(instanceOf(Customer.class)));
+	}
+}

mongodb/pom.xml

@@ -33,7 +33,7 @@
 		</dependency>
 
 		<dependency>
-			<groupId>com.mysema.querydsl</groupId>
+			<groupId>com.querydsl</groupId>
 			<artifactId>querydsl-mongodb</artifactId>
 			<version>${querydsl.version}</version>
 		</dependency>