org.springframework.transaction.support

## Interface TransactionSynchronization

- All Known Implementing Classes:
    ResourceHolderSynchronization, SpringLobCreatorSynchronization, TransactionSynchronizationAdapter

      public interface TransactionSynchronization

  Interface for transaction synchronization callbacks. Supported by AbstractPlatformTransactionManager.

  TransactionSynchronization implementations can implement the Ordered interface to influence their execution order. A synchronization that does not implement the Ordered interface is appended to the end of the synchronization chain.

  System synchronizations performed by Spring itself use specific order values, allowing for fine-grained interaction with their execution order (if necessary).

  Since:
    02.06.2003
  Author:
    Juergen Hoeller
  See Also:
    `TransactionSynchronizationManager`, `AbstractPlatformTransactionManager`, `DataSourceUtils.CONNECTION_SYNCHRONIZATION_ORDER`, `SessionFactoryUtils.SESSION_SYNCHRONIZATION_ORDER`

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static int` | `STATUS_COMMITTED` Completion status in case of proper commit
    `static int` | `STATUS_ROLLED_BACK` Completion status in case of proper rollback
    `static int` | `STATUS_UNKNOWN` Completion status in case of heuristic mixed completion or system errors

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `afterCommit()` Invoked after transaction commit.
    `void` | `afterCompletion(int status)` Invoked after transaction commit/rollback.
    `void` | `beforeCommit(boolean readOnly)` Invoked before transaction commit (before "beforeCompletion").
    `void` | `beforeCompletion()` Invoked before transaction commit/rollback.
    `void` | `flush()` Flush the underlying session to the datastore, if applicable: for example, a Hibernate/JPA session.
    `void` | `resume()` Resume this synchronization.
    `void` | `suspend()` Suspend this synchronization.

- - ### Field Detail

    - #### STATUS_COMMITTED

          static final int STATUS_COMMITTED

      Completion status in case of proper commit
      See Also:
        Constant Field Values

    - #### STATUS_ROLLED_BACK

          static final int STATUS_ROLLED_BACK

      Completion status in case of proper rollback
      See Also:
        Constant Field Values

    - #### STATUS_UNKNOWN

          static final int STATUS_UNKNOWN

      Completion status in case of heuristic mixed completion or system errors
      See Also:
        Constant Field Values

  - ### Method Detail

    - #### suspend

          void suspend()

      Suspend this synchronization. Supposed to unbind resources from TransactionSynchronizationManager if managing any.
      See Also:
        `TransactionSynchronizationManager.unbindResource(java.lang.Object)`

    - #### resume

          void resume()

      Resume this synchronization. Supposed to rebind resources to TransactionSynchronizationManager if managing any.
      See Also:
        `TransactionSynchronizationManager.bindResource(java.lang.Object, java.lang.Object)`

    - #### flush

          void flush()

      Flush the underlying session to the datastore, if applicable: for example, a Hibernate/JPA session.
      See Also:
        `TransactionStatus.flush()`

    - #### beforeCommit

          void beforeCommit(boolean readOnly)

      Invoked before transaction commit (before "beforeCompletion"). Can e.g. flush transactional O/R Mapping sessions to the database.

      This callback does not mean that the transaction will actually be committed. A rollback decision can still occur after this method has been called. This callback is rather meant to perform work that's only relevant if a commit still has a chance to happen, such as flushing SQL statements to the database.

      Note that exceptions will get propagated to the commit caller and cause a rollback of the transaction.

      Parameters:
        `readOnly` - whether the transaction is defined as read-only transaction
      Throws:
        `RuntimeException` - in case of errors; will be propagated to the caller (note: do not throw TransactionException subclasses here!)
      See Also:
        `beforeCompletion()`

    - #### beforeCompletion

          void beforeCompletion()

      Invoked before transaction commit/rollback. Can perform resource cleanup before transaction completion.

      This method will be invoked after `beforeCommit`, even when `beforeCommit` threw an exception. This callback allows for closing resources before transaction completion, for any outcome.

      Throws:
        `RuntimeException` - in case of errors; will be logged but not propagated (note: do not throw TransactionException subclasses here!)
      See Also:
        `beforeCommit(boolean)`, `afterCompletion(int)`

    - #### afterCommit

          void afterCommit()

      Invoked after transaction commit. Can perform further operations right after the main transaction has successfully committed.

      Can e.g. commit further operations that are supposed to follow on a successful commit of the main transaction, like confirmation messages or emails.

      NOTE: The transaction will have been committed already, but the transactional resources might still be active and accessible. As a consequence, any data access code triggered at this point will still "participate" in the original transaction, allowing to perform some cleanup (with no commit following anymore!), unless it explicitly declares that it needs to run in a separate transaction. Hence: Use `PROPAGATION_REQUIRES_NEW` for any transactional operation that is called from here.

      Throws:
        `RuntimeException` - in case of errors; will be propagated to the caller (note: do not throw TransactionException subclasses here!)

    - #### afterCompletion

          void afterCompletion(int status)

      Invoked after transaction commit/rollback. Can perform resource cleanup after transaction completion.

      NOTE: The transaction will have been committed or rolled back already, but the transactional resources might still be active and accessible. As a consequence, any data access code triggered at this point will still "participate" in the original transaction, allowing to perform some cleanup (with no commit following anymore!), unless it explicitly declares that it needs to run in a separate transaction. Hence: Use `PROPAGATION_REQUIRES_NEW` for any transactional operation that is called from here.

      Parameters:
        `status` - completion status according to the `STATUS_*` constants
      Throws:
        `RuntimeException` - in case of errors; will be logged but not propagated (note: do not throw TransactionException subclasses here!)
      See Also:
        `STATUS_COMMITTED`, `STATUS_ROLLED_BACK`, `STATUS_UNKNOWN`, `beforeCompletion()`