Enables Spring's annotation-driven transaction management capability, similar to
the support found in Spring's
<tx:*>
XML namespace. To be used on
@Configuration
classes as follows:
@Configuration
@EnableTransactionManagement
public class AppConfig {
@Bean
public FooRepository fooRepository() {
// configure and return a class having @Transactional methods
return new JdbcFooRepository(dataSource());
}
@Bean
public DataSource dataSource() {
// configure and return the necessary JDBC DataSource
}
@Bean
public PlatformTransactionManager txManager() {
return new DataSourceTransactionManager(dataSource());
}
}
For reference, the example above can be compared to the following Spring XML
configuration:
<beans>
<tx:annotation-driven/>
<bean id="fooRepository" class="com.foo.JdbcFooRepository">
<constructor-arg ref="dataSource"/>
</bean>
<bean id="dataSource" class="com.vendor.VendorDataSource"/>
<bean id="transactionManager" class="org.sfwk...DataSourceTransactionManager">
<constructor-arg ref="dataSource"/>
</bean>
</beans>
In both of the scenarios above,
@EnableTransactionManagement
and
<tx:annotation-driven/>
are responsible for registering the necessary Spring
components that power annotation-driven transaction management, such as the
TransactionInterceptor and the proxy- or AspectJ-based advice that weave the
interceptor into the call stack when
JdbcFooRepository
's
@Transactional
methods are invoked.
A minor difference between the two examples lies in the naming of the PlatformTransactionManager
bean: In the @Bean
case, the name is
"txManager" (per the name of the method); in the XML case, the name is
"transactionManager". The <tx:annotation-driven/>
is hard-wired to
look for a bean named "transactionManager" by default, however
@EnableTransactionManagement
is more flexible; it will fall back to a by-type
lookup for any PlatformTransactionManager
bean in the container. Thus the name
can be "txManager", "transactionManager", or "tm": it simply does not matter.
For those that wish to establish a more direct relationship between
@EnableTransactionManagement
and the exact transaction manager bean to be used,
the TransactionManagementConfigurer
callback interface may be implemented -
notice the implements
clause and the @Override
-annotated method below:
@Configuration
@EnableTransactionManagement
public class AppConfig implements TransactionManagementConfigurer {
@Bean
public FooRepository fooRepository() {
// configure and return a class having @Transactional methods
return new JdbcFooRepository(dataSource());
}
@Bean
public DataSource dataSource() {
// configure and return the necessary JDBC DataSource
}
@Bean
public PlatformTransactionManager txManager() {
return new DataSourceTransactionManager(dataSource());
}
@Override
public PlatformTransactionManager annotationDrivenTransactionManager() {
return txManager();
}
}
This approach may be desirable simply because it is more explicit, or it may be
necessary in order to distinguish between two
PlatformTransactionManager
beans
present in the same container. As the name suggests, the
annotationDrivenTransactionManager()
will be the one used for processing
@Transactional
methods. See
TransactionManagementConfigurer
Javadoc
for further details.
The mode()
attribute controls how advice is applied: If the mode is
AdviceMode.PROXY
(the default), then the other attributes control the behavior
of the proxying. Please note that proxy mode allows for interception of calls through
the proxy only; local calls within the same class cannot get intercepted that way.
Note that if the mode() is set to AdviceMode.ASPECTJ
, then the
value of the proxyTargetClass()
attribute will be ignored. Note also that in
this case the spring-aspects
module JAR must be present on the classpath, with
compile-time weaving or load-time weaving applying the aspect to the affected classes.
There is no proxy involved in such a scenario; local calls will be intercepted as well.