#69 - Added example for how to set up Spring Data JPA with two DataSources.

jpa/multiple-datasources/src/main/java/example/springdata/jpa/multipleds/Application.java

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+/*
+ * 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.multipleds;
+
+import javax.annotation.PostConstruct;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
+import org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration;
+import org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration;
+import org.springframework.transaction.annotation.EnableTransactionManagement;
+
+import example.springdata.jpa.multipleds.customer.Customer.CustomerId;
+
+/**
+ * Core Spring Boot application configuration. Note, that we explicitly deactivate some auto-configurations explicitly.
+ * They mostly will even disable automatically if special bean names are used (e.g. {@code entityManagerFactory}) but I
+ * wanted to keep the two configurations symmetric. The configuration classes being located in separate packages serves
+ * the purpose of scoping the Spring Data repository scanning to those packages so that the infrastructure setup is
+ * attached to the corresponding repository instances.
+ * 
+ * @author Oliver Gierke
+ * @see example.springdata.jpa.multipleds.customer.CustomerConfig
+ * @see example.springdata.jpa.multipleds.order.OrderConfig
+ */
+@SpringBootApplication(exclude = { DataSourceAutoConfiguration.class, HibernateJpaAutoConfiguration.class,
+		DataSourceTransactionManagerAutoConfiguration.class })
+@EnableTransactionManagement
+public class Application {
+
+	public static void main(String[] args) {
+		SpringApplication.run(Application.class, args);
+	}
+
+	@Autowired DataInitializer initializer;
+
+	@PostConstruct
+	public void init() {
+
+		CustomerId customerId = initializer.initializeCustomer();
+		initializer.initializeOrder(customerId);
+	}
+}

jpa/multiple-datasources/src/main/java/example/springdata/jpa/multipleds/DataInitializer.java

@@ -0,0 +1,82 @@
+/*
+ * 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.multipleds;
+
+import javax.sql.DataSource;
+
+import lombok.NonNull;
+import lombok.RequiredArgsConstructor;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+import org.springframework.transaction.annotation.Transactional;
+import org.springframework.util.Assert;
+
+import example.springdata.jpa.multipleds.customer.Customer;
+import example.springdata.jpa.multipleds.customer.Customer.CustomerId;
+import example.springdata.jpa.multipleds.customer.CustomerRepository;
+import example.springdata.jpa.multipleds.order.Order;
+import example.springdata.jpa.multipleds.order.Order.LineItem;
+import example.springdata.jpa.multipleds.order.OrderRepository;
+
+/**
+ * Sample component to demonstrate how to work with repositories backed by different {@link DataSource}s. Note how we
+ * explicitly select a transaction manager by name. In this particular case (only one operation on the repository) this
+ * is not strictly necessary. However, if multiple repositories or multiple interactions on the very same repsoitory are
+ * to be executed in a method we need to expand the transaction boundary around these interactions. It's recommended to
+ * create a dedicated annotation meta-annotated with {@code @Transactional("…")} to be able to refer to a particular
+ * datasource without using String qualifiers.
+ * <p>
+ * Also, not that one cannot interact with both databases in a single, transactional method as transactions are thread
+ * bound in Spring an thus only a single transaction can be active in a single thread. See {@link Application#init()}
+ * for how to orchestrate the calls.
+ * 
+ * @author Oliver Gierke
+ */
+@Component
+@RequiredArgsConstructor(onConstructor = @__(@Autowired))
+public class DataInitializer {
+
+	private final @NonNull OrderRepository orders;
+	private final @NonNull CustomerRepository customers;
+
+	/**
+	 * Initializes a {@link Customer}.
+	 * 
+	 * @return
+	 */
+	@Transactional("customerTransactionManager")
+	public CustomerId initializeCustomer() {
+		return customers.save(new Customer("Dave", "Matthews")).getId();
+	}
+
+	/**
+	 * Initializes an {@link Order}.
+	 * 
+	 * @param customer must not be {@literal null}.
+	 * @return
+	 */
+	@Transactional("orderTransactionManager")
+	public Order initializeOrder(CustomerId customer) {
+
+		Assert.notNull(customer, "Custoemr identifier must not be null!");
+
+		Order order = new Order(customer);
+		order.add(new LineItem("Lakewood Guitar"));
+
+		return orders.save(order);
+	}
+}

jpa/multiple-datasources/src/main/java/example/springdata/jpa/multipleds/customer/Customer.java

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+/*
+ * 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.multipleds.customer;
+
+import java.io.Serializable;
+
+import javax.persistence.Embeddable;
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+
+import lombok.EqualsAndHashCode;
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+import lombok.ToString;
+import lombok.Value;
+
+/**
+ * Simple domain class representing a {@link Customer}.
+ * 
+ * @author Oliver Gierke
+ */
+@Entity
+@EqualsAndHashCode(of = "id")
+@Getter
+@RequiredArgsConstructor
+@ToString
+public class Customer {
+
+	private @Id @GeneratedValue Long id;
+	private final String firstname, lastname;
+
+	Customer() {
+		this.firstname = null;
+		this.lastname = null;
+	}
+
+	public CustomerId getId() {
+		return new CustomerId(id);
+	}
+
+	@Value
+	@Embeddable
+	@RequiredArgsConstructor
+	@SuppressWarnings("serial")
+	public static class CustomerId implements Serializable {
+
+		private final Long customerId;
+
+		CustomerId() {
+			this.customerId = null;
+		}
+	}
+}

jpa/multiple-datasources/src/main/java/example/springdata/jpa/multipleds/customer/CustomerConfig.java

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+/*
+ * 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.multipleds.customer;
+
+import javax.persistence.EntityManagerFactory;
+import javax.sql.DataSource;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
+import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseBuilder;
+import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseType;
+import org.springframework.orm.jpa.JpaTransactionManager;
+import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
+import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
+import org.springframework.transaction.PlatformTransactionManager;
+
+/**
+ * Configuration for the {@link Customer} slice of the system. A dedicated {@link DataSource},
+ * {@link JpaTransactionManager} and {@link EntityManagerFactory}. Note that there could of course be some deduplication
+ * with {@link example.springdata.jpa.multipleds.order.OrderConfig}. I just decided to keep it to focus on the
+ * sepeartion of the two. Also, some overlaps might not even occur in real world scenarios (whether to create DDl or the
+ * like).
+ *
+ * @author Oliver Gierke
+ */
+@Configuration
+@EnableJpaRepositories(entityManagerFactoryRef = "customerEntityManagerFactory",
+		transactionManagerRef = "customerTransactionManager")
+class CustomerConfig {
+
+	@Bean
+	PlatformTransactionManager customerTransactionManager() {
+		return new JpaTransactionManager(customerEntityManagerFactory().getObject());
+	}
+
+	@Bean
+	LocalContainerEntityManagerFactoryBean customerEntityManagerFactory() {
+
+		HibernateJpaVendorAdapter jpaVendorAdapter = new HibernateJpaVendorAdapter();
+		jpaVendorAdapter.setGenerateDdl(true);
+
+		LocalContainerEntityManagerFactoryBean factoryBean = new LocalContainerEntityManagerFactoryBean();
+
+		factoryBean.setDataSource(customerDataSource());
+		factoryBean.setJpaVendorAdapter(jpaVendorAdapter);
+		factoryBean.setPackagesToScan(CustomerConfig.class.getPackage().getName());
+
+		return factoryBean;
+	}
+
+	@Bean
+	DataSource customerDataSource() {
+
+		return new EmbeddedDatabaseBuilder().//
+				setType(EmbeddedDatabaseType.HSQL).//
+				setName("customers").//
+				build();
+	}
+}

jpa/multiple-datasources/src/main/java/example/springdata/jpa/multipleds/customer/CustomerRepository.java

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+/*
+ * 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.multipleds.customer;
+
+import java.util.Optional;
+
+import org.springframework.data.repository.CrudRepository;
+
+/**
+ * Spring Data repository to manage {@link Customer}s.
+ * 
+ * @author Oliver Gierke
+ */
+public interface CustomerRepository extends CrudRepository<Customer, Long> {
+
+	Optional<Customer> findByLastname(String lastname);
+}

jpa/multiple-datasources/src/main/java/example/springdata/jpa/multipleds/order/Order.java

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+/*
+ * 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.multipleds.order;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import javax.persistence.CascadeType;
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.OneToMany;
+import javax.persistence.Table;
+
+import lombok.EqualsAndHashCode;
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+import lombok.ToString;
+
+import org.springframework.util.Assert;
+
+import example.springdata.jpa.multipleds.customer.Customer.CustomerId;
+
+/**
+ * Simple domain class representing an {@link Order}
+ * 
+ * @author Oliver Gierke
+ */
+@Entity
+@EqualsAndHashCode(of = "id")
+@Getter
+@RequiredArgsConstructor
+@ToString
+// Needs to be explicitly named as Order is a reserved keyword
+@Table(name = "SampleOrder")
+public class Order {
+
+	private @Id @GeneratedValue Long id;
+
+	@OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)//
+	private final List<LineItem> lineItems = new ArrayList<LineItem>();
+	private final CustomerId customer;
+
+	Order() {
+		this.customer = null;
+	}
+
+	/**
+	 * Adds a {@link LineItem} to the {@link Order}.
+	 * 
+	 * @param lineItem must not be {@literal null}.
+	 */
+	public void add(LineItem lineItem) {
+
+		Assert.notNull(lineItem, "Line item must not be null!");
+
+		this.lineItems.add(lineItem);
+	}
+
+	@Entity
+	@EqualsAndHashCode(of = "id")
+	@Getter
+	@RequiredArgsConstructor
+	@ToString
+	@Table(name = "LineItem")
+	public static class LineItem {
+
+		private @Id @GeneratedValue Long id;
+		private final String description;
+	}
+}

jpa/multiple-datasources/src/main/java/example/springdata/jpa/multipleds/order/OrderConfig.java

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+/*
+ * 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.multipleds.order;
+
+import javax.persistence.EntityManagerFactory;
+import javax.sql.DataSource;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
+import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseBuilder;
+import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseType;
+import org.springframework.orm.jpa.JpaTransactionManager;
+import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
+import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
+import org.springframework.transaction.PlatformTransactionManager;
+
+/**
+ * Configuration for the {@link Order} slice of the system. A dedicated {@link DataSource},
+ * {@link JpaTransactionManager} and {@link EntityManagerFactory}. Note that there could of course be some deduplication
+ * with {@link example.springdata.jpa.multipleds.customer.CustomerConfig}. I just decided to keep it to focus on the
+ * sepeartion of the two. Also, some overlaps might not even occur in real world scenarios (whether to create DDl or the
+ * like).
+ *
+ * @author Oliver Gierke
+ */
+@Configuration
+@EnableJpaRepositories(entityManagerFactoryRef = "orderEntityManagerFactory",
+		transactionManagerRef = "orderTransactionManager")
+class OrderConfig {
+
+	@Bean
+	PlatformTransactionManager orderTransactionManager() {
+		return new JpaTransactionManager(orderEntityManagerFactory().getObject());
+	}
+
+	@Bean
+	LocalContainerEntityManagerFactoryBean orderEntityManagerFactory() {
+
+		HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
+		vendorAdapter.setGenerateDdl(true);
+
+		LocalContainerEntityManagerFactoryBean factoryBean = new LocalContainerEntityManagerFactoryBean();
+
+		factoryBean.setDataSource(orderDataSource());
+		factoryBean.setJpaVendorAdapter(vendorAdapter);
+		factoryBean.setPackagesToScan(OrderConfig.class.getPackage().getName());
+
+		return factoryBean;
+	}
+
+	@Bean
+	DataSource orderDataSource() {
+
+		return new EmbeddedDatabaseBuilder().//
+				setType(EmbeddedDatabaseType.HSQL).//
+				setName("orders").//
+				build();
+	}
+}

jpa/multiple-datasources/src/main/java/example/springdata/jpa/multipleds/order/OrderRepository.java

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+/*
+ * 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.multipleds.order;
+
+import java.util.List;
+
+import org.springframework.data.repository.CrudRepository;
+
+import example.springdata.jpa.multipleds.customer.Customer;
+import example.springdata.jpa.multipleds.customer.Customer.CustomerId;
+
+/**
+ * Spring Data repository managing {@link Order}s.
+ * 
+ * @author Oliver Gierke
+ */
+public interface OrderRepository extends CrudRepository<Order, Long> {
+
+	/**
+	 * Returns all {@link Order}s for the {@link Customer} with the given identifier.
+	 * 
+	 * @param id must not be {@literal null}.
+	 * @return
+	 */
+	List<Order> findByCustomer(CustomerId id);
+}

jpa/multiple-datasources/src/test/java/example/springdata/jpa/multipleds/customer/CustomerRepositoryTests.java

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+/*
+ * 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.multipleds.customer;
+
+import static org.hamcrest.CoreMatchers.*;
+import static org.junit.Assert.*;
+
+import java.util.Optional;
+
+import javax.persistence.EntityManager;
+import javax.transaction.Transactional;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.boot.test.SpringApplicationConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.test.context.transaction.TransactionConfiguration;
+
+import example.springdata.jpa.multipleds.Application;
+
+/**
+ * Integration test for {@link CustomerRepository}.
+ * 
+ * @author Oliver Gierke
+ */
+@RunWith(SpringJUnit4ClassRunner.class)
+@SpringApplicationConfiguration(classes = Application.class)
+@Transactional
+@TransactionConfiguration(transactionManager = "customerTransactionManager")
+public class CustomerRepositoryTests {
+
+	@Autowired CustomerRepository repository;
+	@Autowired @Qualifier("customerEntityManagerFactory") EntityManager em;
+
+	@Test
+	public void findsCustomerByLastname() {
+
+		Optional<Customer> result = repository.findByLastname("Matthews");
+
+		assertThat(result, is(not(Optional.empty())));
+		assertThat(result.get().getFirstname(), is("Dave"));
+	}
+}

jpa/multiple-datasources/src/test/java/example/springdata/jpa/multipleds/order/OrderRepositoryTests.java

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+/*
+ * 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.multipleds.order;
+
+import static org.hamcrest.Matchers.*;
+import static org.junit.Assert.*;
+
+import javax.transaction.Transactional;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.SpringApplicationConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.test.context.transaction.TransactionConfiguration;
+
+import example.springdata.jpa.multipleds.Application;
+import example.springdata.jpa.multipleds.customer.CustomerRepository;
+
+/**
+ * Integration test for {@link CustomerRepository}.
+ * 
+ * @author Oliver Gierke
+ */
+@RunWith(SpringJUnit4ClassRunner.class)
+@SpringApplicationConfiguration(classes = Application.class)
+@Transactional
+@TransactionConfiguration(transactionManager = "orderTransactionManager")
+public class OrderRepositoryTests {
+
+	@Autowired OrderRepository orders;
+	@Autowired CustomerRepository customers;
+
+	@Test
+	public void persistsAndFindsCustomer() {
+
+		customers.findAll().forEach(customer -> {
+			assertThat(orders.findByCustomer(customer.getId()), hasSize(1));
+		});
+	}
+}