Spring - Is it possible to use multiple transaction managers in the same application?

Question

I'm new to Spring and I'm wondering if its possible to use numerous transaction managers in the same application?

I have two data access layers - one for both of the databases. I'm wondering, how do you go about using one transaction managers for one layer and different transaction manager for the other layer. I don't need to perform transactions across both databases - yet. But I do need perform transactions on each database individually. I've created an image to help outline my problem:

Here is my application context configuration:

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-3.0.xsd
        http://www.springframework.org/schema/tx
        http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">

    <context:component-scan base-package="cheetah.repositories" />
    <tx:annotation-driven />

    <bean id="entityManagerFactory"
        class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean">
        <property name="persistenceUnitName" value="accounts" />
    </bean>

    <bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />

    <bean id="transactionManager"
        class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory" />
    </bean>

</beans>

Here is an example that uses this configuration:

@Repository
public class JpaAccountRepository implements AccountRepository {

    @PersistenceContext(unitName = "cheetahAccounts")
    private EntityManager accountManager;

    @Override
    @Transactional
    public Account findById(long id) {

        Account account = accountManager.find(Account.class, id);
        return account;
    }
}

So for the account repository, I want to use an entity manager factory with the persistence unit set to accounts. However, with my BusinessData Repository, I want to use an entity manager factory with a different persistence unit. Since I can only define one transaction manager bean, how can I go about using different transaction managers for the different repositories?

Thanks for any help.

Answer 1

Where you use a @Transactional annotation, you can specify the transaction manager to use by adding an attribute set to a bean name or qualifier. For example, if your application context defines multiple transaction managers with qualifiers:

<bean id="transactionManager1"
    class="org.springframework.orm.jpa.JpaTransactionManager">
    <property name="entityManagerFactory" ref="entityManagerFactory1" />
    <qualifier value="account"/>
</bean>

<bean id="transactionManager2"
    class="org.springframework.orm.jpa.JpaTransactionManager">
    <property name="entityManagerFactory" ref="entityManagerFactory2" />
    <qualifier value="businessData"/>
</bean>

You can use the qualifier to specify the transaction manager to use:

public class TransactionalService {

    @Transactional("account")
    public void setSomethingInAccount() { ... }

    @Transactional("businessData")
    public void doSomethingInBusinessData() { ... }
}