#106 - Add example with CompletableFuture and Java 8 for JPA.

Simple test case that demonstrates CompletableFuture.

Original pull request: #106.

jpa/java8/pom.xml

@@ -8,7 +8,11 @@
 		<version>1.0.0.BUILD-SNAPSHOT</version>
 	</parent>
 
+	<properties>
+		<spring.version>4.2.0.BUILD-SNAPSHOT</spring.version>
+		<spring-data-releasetrain.version>Gosling-BUILD-SNAPSHOT</spring-data-releasetrain.version>
+	</properties>
+
 	<artifactId>spring-data-jpa-java8</artifactId>
 	<name>Spring Data JPA - Java 8 specific features</name>
-
 </project>

jpa/java8/src/main/java/example/springdata/jpa/java8/AuditingConfiguration.java

@@ -20,8 +20,10 @@ import org.springframework.boot.orm.jpa.EntityScan;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.data.jpa.convert.threeten.Jsr310JpaConverters;
 import org.springframework.data.jpa.repository.config.EnableJpaAuditing;
+import org.springframework.scheduling.annotation.EnableAsync;
 
 @Configuration
+@EnableAsync
 @EnableAutoConfiguration
 @EntityScan(basePackageClasses = { AuditingConfiguration.class, Jsr310JpaConverters.class })
 @EnableJpaAuditing

jpa/java8/src/main/java/example/springdata/jpa/java8/Customer.java

@@ -15,19 +15,26 @@
  */
 package example.springdata.jpa.java8;
 
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.ToString;
+
 import javax.persistence.Entity;
 
 /**
  * @author Oliver Gierke
+ * @author Thomas Darimont
  */
 @Entity
+@Getter
+@ToString
+@AllArgsConstructor
 public class Customer extends AbstractEntity {
 
 	String firstname, lastname;
 
-	public Customer(String firstname, String lastname) {
-
-		this.firstname = firstname;
-		this.lastname = lastname;
+	protected Customer() {
+		this.firstname = null;
+		this.lastname = null;
 	}
 }

jpa/java8/src/main/java/example/springdata/jpa/java8/CustomerRepository.java

@@ -15,12 +15,15 @@
  */
 package example.springdata.jpa.java8;
 
+import java.util.List;
 import java.util.Optional;
+import java.util.concurrent.CompletableFuture;
 import java.util.stream.Stream;
 
 import org.springframework.data.jpa.repository.Query;
 import org.springframework.data.repository.CrudRepository;
 import org.springframework.data.repository.Repository;
+import org.springframework.scheduling.annotation.Async;
 
 /**
  * Repository to manage {@link Customer} instances.
@@ -80,4 +83,7 @@ public interface CustomerRepository extends Repository<Customer, Long> {
 	 * @return
 	 */
 	Stream<Customer> findAllByLastnameIsNotNull();
+
+	@Async
+	CompletableFuture<List<Customer>> readAllBy();
 }

jpa/java8/src/test/java/example/springdata/jpa/java8/Java8IntegrationTests.java

@@ -19,14 +19,17 @@ import static org.hamcrest.Matchers.*;
 import static org.junit.Assert.*;
 
 import java.util.Optional;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.TimeUnit;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.test.context.ContextConfiguration;
+import org.springframework.boot.test.SpringApplicationConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.transaction.annotation.Propagation;
 import org.springframework.transaction.annotation.Transactional;
 
 /**
@@ -36,7 +39,7 @@ import org.springframework.transaction.annotation.Transactional;
  * @author Thomas Darimont
  */
 @RunWith(SpringJUnit4ClassRunner.class)
-@ContextConfiguration(classes = AuditingConfiguration.class)
+@SpringApplicationConfiguration(classes = AuditingConfiguration.class)
 @Transactional
 public class Java8IntegrationTests {
 
@@ -99,4 +102,35 @@ public class Java8IntegrationTests {
 			assertThat(stream.collect(Collectors.toList()), hasItems(customer1, customer2));
 		}
 	}
+
+	/**
+	 * Here we demonstrate the usage of CompletableFuture as a result wrapper for asynchronous 
+	 * Repository query methods.
+	 * 
+	 * Note that we need to disable the surrounding TX to be able to asynchronously read the wirtten 
+	 * data from from another thread within the same test method.
+	 */
+	@Test
+	@Transactional(propagation = Propagation.NOT_SUPPORTED)
+	public void supportsCompletableFuturesAsReturnTypeWrapper() throws Exception {
+
+		repository.save(new Customer("Customer1", "Foo"));
+		repository.save(new Customer("Customer2", "Bar"));
+
+		CompletableFuture<Void> future = repository.readAllBy().thenAccept(customers -> {
+			
+			assertThat(customers, hasSize(2));
+			
+			customers.forEach(System.out::println);
+			System.out.println("Completed!");
+		});
+
+		while (!future.isDone()) {
+			System.out.println("waiting...");
+			TimeUnit.MILLISECONDS.sleep(500);
+		}
+
+		future.get();
+		System.out.println("Done");
+	}
 }

jpa/java8/src/test/resources/application.properties

@@ -0,0 +1,4 @@
+#logging.level.org.springframework=INFO
+#logging.level.org.springframework.orm=TRACE
+#logging.level.org.springframework.transaction=TRACE
+#logging.level.org.hsqldb=TRACE

jpa/java8/src/test/resources/logback.xml

@@ -1,18 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<configuration>
-
-	<appender name="console" class="ch.qos.logback.core.ConsoleAppender">
-		<encoder>
-			<pattern>%d %5p %40.40c:%4L - %m%n</pattern>
-		</encoder>
-	</appender>
-
-	<logger name="org.springframework" level="info" />
-	<logger name="org.springframework.boot" level="debug" />
-	<logger name="org.hibernate.tool.hbm2ddl" level="trace" />
-
-	<root level="error">
-		<appender-ref ref="console" />
-	</root>
-
-</configuration>

jpa/pom.xml

@@ -39,6 +39,11 @@
 			<artifactId>joda-time</artifactId>
 		</dependency>
 
+		<!-- <dependency> -->
+		<!-- <groupId>com.h2database</groupId> -->
+		<!-- <artifactId>h2</artifactId> -->
+		<!-- </dependency> -->
+
 		<dependency>
 			<groupId>org.hsqldb</groupId>
 			<artifactId>hsqldb</artifactId>