10.6 Programmatic transaction management

The Spring Framework provides two means of programmatic transaction management:

The Spring team generally recommends the TransactionTemplate for programmatic transaction management. The second approach is similar to using the JTA UserTransaction API, although exception handling is less cumbersome.

10.6.1 Using the TransactionTemplate

The TransactionTemplate adopts the same approach as other Spring templates such as the JdbcTemplate. It uses a callback approach, to free application code from having to do the boilerplate acquisition and release of transactional resources, and results in code that is intention driven, in that the code that is written focuses solely on what the developer wants to do.

[Note]Note

As you will see in the examples that follow, using the TransactionTemplate absolutely couples you to Spring's transaction infrastructure and APIs. Whether or not programmatic transaction management is suitable for your development needs is a decision that you will have to make yourself.

Application code that must execute in a transactional context, and that will use the TransactionTemplate explicitly, looks like the following. You, as an application developer, write a TransactionCallback implementation (typically expressed as an anonymous inner class) that contains the code that you need to execute in the context of a transaction. You then pass an instance of your custom TransactionCallback to the execute(..) method exposed on the TransactionTemplate.

public class SimpleService implements Service {

  // single TransactionTemplate shared amongst all methods in this instance
  private final TransactionTemplate transactionTemplate;

  // use constructor-injection to supply the PlatformTransactionManager
  public SimpleService(PlatformTransactionManager transactionManager) {
    Assert.notNull(transactionManager, "The 'transactionManager' argument must not be null.");
    this.transactionTemplate = new TransactionTemplate(transactionManager);
  }

  public Object someServiceMethod() {
    return transactionTemplate.execute(new TransactionCallback() {

      // the code in this method executes in a transactional context
      public Object doInTransaction(TransactionStatus status) {
        updateOperation1();
        return resultOfUpdateOperation2();
      }
    });
  }
}

If there is no return value, use the convenient TransactionCallbackWithoutResult class with an anonymous class as follows:

transactionTemplate.execute(new TransactionCallbackWithoutResult() {

  protected void doInTransactionWithoutResult(TransactionStatus status) {
    updateOperation1();
    updateOperation2();
  }
});

Code within the callback can roll the transaction back by calling the setRollbackOnly() method on the supplied TransactionStatus object:

transactionTemplate.execute(new TransactionCallbackWithoutResult() {

  protected void doInTransactionWithoutResult(TransactionStatus status) {
    try {
      updateOperation1();
      updateOperation2();
    } catch (SomeBusinessExeption ex) {
      status.setRollbackOnly();
    }
  }
});

10.6.1.1 Specifying transaction settings

You can specify transaction settings such as the propagation mode, the isolation level, the timeout, and so forth on the TransactionTemplate either programmatically or in configuration. TransactionTemplate instances by default have the default transactional settings. The following example shows the programmatic customization of the transactional settings for a specific TransactionTemplate:

public class SimpleService implements Service {

  private final TransactionTemplate transactionTemplate;

  public SimpleService(PlatformTransactionManager transactionManager) {
    Assert.notNull(transactionManager, "The 'transactionManager' argument must not be null.");
    this.transactionTemplate = new TransactionTemplate(transactionManager);

    // the transaction settings can be set here explicitly if so desired
    this.transactionTemplate.setIsolationLevel(TransactionDefinition.ISOLATION_READ_UNCOMMITTED);
    this.transactionTemplate.setTimeout(30); // 30 seconds
    // and so forth...
  }
}

The following example defines a TransactionTemplate with some custom transactional settings, using Spring XML configuration. The sharedTransactionTemplate can then be injected into as many services as are required.

<bean id="sharedTransactionTemplate"
    class="org.springframework.transaction.support.TransactionTemplate">
  <property name="isolationLevelName" value="ISOLATION_READ_UNCOMMITTED"/>
  <property name="timeout" value="30"/>
</bean>"

Finally, instances of the TransactionTemplate class are threadsafe, in that instances do not maintain any conversational state. TransactionTemplate instances do however maintain configuration state, so while a number of classes may share a single instance of a TransactionTemplate, if a class needs to use a TransactionTemplate with different settings (for example, a different isolation level), then you need to create two distinct TransactionTemplate instances.

10.6.2 Using the PlatformTransactionManager

You can also use the org.springframework.transaction.PlatformTransactionManager directly to manage your transaction. Simply pass the implementation of the PlatformTransactionManager you are using to your bean through a bean reference. Then, using the TransactionDefinition and TransactionStatus objects you can initiate transactions, roll back, and commit.

DefaultTransactionDefinition def = new DefaultTransactionDefinition();
// explicitly setting the transaction name is something that can only be done programmatically
def.setName("SomeTxName");
def.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRED);

TransactionStatus status = txManager.getTransaction(def);
try {
  // execute your business logic here
}
catch (MyException ex) {
  txManager.rollback(status);
  throw ex;
}
txManager.commit(status);