org.springframework.transaction.reactive

Class TransactionSynchronizationManager

java.lang.Object

org.springframework.transaction.reactive.TransactionSynchronizationManager

public class TransactionSynchronizationManager
extends Object

Central delegate that manages resources and transaction synchronizations per subscriber context. To be used by resource management code but not by typical application code.

Supports one resource per key without overwriting, that is, a resource needs to be removed before a new one can be set for the same key. Supports a list of transaction synchronizations if synchronization is active.

Resource management code should check for context-bound resources, e.g. database connections, via getResource. Such code is normally not supposed to bind resources to units of work, as this is the responsibility of transaction managers. A further option is to lazily bind on first use if transaction synchronization is active, for performing transactions that span an arbitrary number of resources.

Transaction synchronization must be activated and deactivated by a transaction manager via initSynchronization() and clearSynchronization(). This is automatically supported by AbstractReactiveTransactionManager, and thus by all standard Spring transaction managers.

Resource management code should only register synchronizations when this manager is active, which can be checked via isSynchronizationActive(); it should perform immediate resource cleanup else. If transaction synchronization isn't active, there is either no current transaction, or the transaction manager doesn't support transaction synchronization.

Synchronization is for example used to always return the same resources within a transaction, e.g. a database connection for any given connection factory.

Since:

5.2

Author:

Mark Paluch, Juergen Hoeller

See Also:

isSynchronizationActive(), registerSynchronization(org.springframework.transaction.reactive.TransactionSynchronization), TransactionSynchronization

Constructor Summary

Constructors

Constructor and Description
TransactionSynchronizationManager(TransactionContext transactionContext)

Method Summary

Modifier and Type	Method and Description
void	bindResource(Object key, Object value) Bind the given resource for the given key to the current context.
void	clear() Clear the entire transaction synchronization state: registered synchronizations as well as the various transaction characteristics.
void	clearSynchronization() Deactivate transaction synchronization for the current context.
static reactor.core.publisher.Mono<TransactionSynchronizationManager>	forCurrentTransaction() Get the TransactionSynchronizationManager that is associated with the current transaction context.
Integer	getCurrentTransactionIsolationLevel() Return the isolation level for the current transaction, if any.
String	getCurrentTransactionName() Return the name of the current transaction, or null if none set.
Object	getResource(Object key) Retrieve a resource for the given key that is bound to the current thread.
List<TransactionSynchronization>	getSynchronizations() Return an unmodifiable snapshot list of all registered synchronizations for the current context.
boolean	hasResource(Object key) Check if there is a resource for the given key bound to the current thread.
void	initSynchronization() Activate transaction synchronization for the current context.
boolean	isActualTransactionActive() Return whether there currently is an actual transaction active.
boolean	isCurrentTransactionReadOnly() Return whether the current transaction is marked as read-only.
boolean	isSynchronizationActive() Return if transaction synchronization is active for the current context.
void	registerSynchronization(TransactionSynchronization synchronization) Register a new transaction synchronization for the current context.
void	setActualTransactionActive(boolean active) Expose whether there currently is an actual transaction active.
void	setCurrentTransactionIsolationLevel(Integer isolationLevel) Expose an isolation level for the current transaction.
void	setCurrentTransactionName(String name) Expose the name of the current transaction, if any.
void	setCurrentTransactionReadOnly(boolean readOnly) Expose a read-only flag for the current transaction.
Object	unbindResource(Object key) Unbind a resource for the given key from the current context.
Object	unbindResourceIfPossible(Object key) Unbind a resource for the given key from the current context.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TransactionSynchronizationManager

public TransactionSynchronizationManager(TransactionContext transactionContext)

Method Detail

forCurrentTransaction

public static reactor.core.publisher.Mono<TransactionSynchronizationManager> forCurrentTransaction()

Get the TransactionSynchronizationManager that is associated with the current transaction context.

Mainly intended for code that wants to bind resources or synchronizations.

Throws:

NoTransactionException - if the transaction info cannot be found — for example, because the method was invoked outside a managed transaction

hasResource

public boolean hasResource(Object key)

Check if there is a resource for the given key bound to the current thread.

Parameters:

key - the key to check (usually the resource factory)

Returns:

if there is a value bound to the current thread

getResource

@Nullable
public Object getResource(Object key)

Retrieve a resource for the given key that is bound to the current thread.

Parameters:

key - the key to check (usually the resource factory)

Returns:

a value bound to the current thread (usually the active resource object), or null if none

bindResource

public void bindResource(Object key,
                         Object value)
                  throws IllegalStateException

Bind the given resource for the given key to the current context.

Parameters:

key - the key to bind the value to (usually the resource factory)

value - the value to bind (usually the active resource object)

Throws:

IllegalStateException - if there is already a value bound to the context

unbindResource

public Object unbindResource(Object key)
                      throws IllegalStateException

Unbind a resource for the given key from the current context.

Parameters:

key - the key to unbind (usually the resource factory)

Returns:

the previously bound value (usually the active resource object)

Throws:

IllegalStateException - if there is no value bound to the context

unbindResourceIfPossible

@Nullable
public Object unbindResourceIfPossible(Object key)

Unbind a resource for the given key from the current context.

Parameters:

key - the key to unbind (usually the resource factory)

Returns:

the previously bound value, or null if none bound

isSynchronizationActive

public boolean isSynchronizationActive()

Return if transaction synchronization is active for the current context. Can be called before register to avoid unnecessary instance creation.

See Also:

registerSynchronization(org.springframework.transaction.reactive.TransactionSynchronization)

initSynchronization

public void initSynchronization()
                         throws IllegalStateException

Activate transaction synchronization for the current context. Called by a transaction manager on transaction begin.

Throws:

IllegalStateException - if synchronization is already active

registerSynchronization

public void registerSynchronization(TransactionSynchronization synchronization)
                             throws IllegalStateException

Register a new transaction synchronization for the current context. Typically called by resource management code.

Note that synchronizations can implement the Ordered interface. They will be executed in an order according to their order value (if any).

Parameters:

synchronization - the synchronization object to register

Throws:

IllegalStateException - if transaction synchronization is not active

See Also:

Ordered

getSynchronizations

public List<TransactionSynchronization> getSynchronizations()
                                                     throws IllegalStateException

Return an unmodifiable snapshot list of all registered synchronizations for the current context.

Returns:

unmodifiable List of TransactionSynchronization instances

Throws:

IllegalStateException - if synchronization is not active

See Also:

TransactionSynchronization

clearSynchronization

public void clearSynchronization()
                          throws IllegalStateException

Deactivate transaction synchronization for the current context. Called by the transaction manager on transaction cleanup.

Throws:

IllegalStateException - if synchronization is not active

setCurrentTransactionName

public void setCurrentTransactionName(@Nullable
                                      String name)

Expose the name of the current transaction, if any. Called by the transaction manager on transaction begin and on cleanup.

Parameters:

name - the name of the transaction, or null to reset it

See Also:

TransactionDefinition.getName()

getCurrentTransactionName

@Nullable
public String getCurrentTransactionName()

Return the name of the current transaction, or null if none set. To be called by resource management code for optimizations per use case, for example to optimize fetch strategies for specific named transactions.

See Also:

TransactionDefinition.getName()

setCurrentTransactionReadOnly

public void setCurrentTransactionReadOnly(boolean readOnly)

Expose a read-only flag for the current transaction. Called by the transaction manager on transaction begin and on cleanup.

Parameters:

readOnly - true to mark the current transaction as read-only; false to reset such a read-only marker

See Also:

TransactionDefinition.isReadOnly()

isCurrentTransactionReadOnly

public boolean isCurrentTransactionReadOnly()

Return whether the current transaction is marked as read-only. To be called by resource management code when preparing a newly created resource.

Note that transaction synchronizations receive the read-only flag as argument for the beforeCommit callback, to be able to suppress change detection on commit. The present method is meant to be used for earlier read-only checks.

See Also:

TransactionDefinition.isReadOnly(), TransactionSynchronization.beforeCommit(boolean)

setCurrentTransactionIsolationLevel

public void setCurrentTransactionIsolationLevel(@Nullable
                                                Integer isolationLevel)

Expose an isolation level for the current transaction. Called by the transaction manager on transaction begin and on cleanup.

Parameters:

isolationLevel - the isolation level to expose, according to the R2DBC Connection constants (equivalent to the corresponding Spring TransactionDefinition constants), or null to reset it

See Also:

TransactionDefinition.ISOLATION_READ_UNCOMMITTED, TransactionDefinition.ISOLATION_READ_COMMITTED, TransactionDefinition.ISOLATION_REPEATABLE_READ, TransactionDefinition.ISOLATION_SERIALIZABLE, TransactionDefinition.getIsolationLevel()

getCurrentTransactionIsolationLevel

@Nullable
public Integer getCurrentTransactionIsolationLevel()

Return the isolation level for the current transaction, if any. To be called by resource management code when preparing a newly created resource (for example, a R2DBC Connection).

Returns:

the currently exposed isolation level, according to the R2DBC Connection constants (equivalent to the corresponding Spring TransactionDefinition constants), or null if none

See Also:

TransactionDefinition.ISOLATION_READ_UNCOMMITTED, TransactionDefinition.ISOLATION_READ_COMMITTED, TransactionDefinition.ISOLATION_REPEATABLE_READ, TransactionDefinition.ISOLATION_SERIALIZABLE, TransactionDefinition.getIsolationLevel()

setActualTransactionActive

public void setActualTransactionActive(boolean active)

Expose whether there currently is an actual transaction active. Called by the transaction manager on transaction begin and on cleanup.

Parameters:

active - true to mark the current context as being associated with an actual transaction; false to reset that marker

isActualTransactionActive

public boolean isActualTransactionActive()

Return whether there currently is an actual transaction active. This indicates whether the current context is associated with an actual transaction rather than just with active transaction synchronization.

To be called by resource management code that wants to discriminate between active transaction synchronization (with or without backing resource transaction; also on PROPAGATION_SUPPORTS) and an actual transaction being active (with backing resource transaction; on PROPAGATION_REQUIRED, PROPAGATION_REQUIRES_NEW, etc).

See Also:

isSynchronizationActive()

clear

public void clear()

Clear the entire transaction synchronization state: registered synchronizations as well as the various transaction characteristics.

See Also:

clearSynchronization(), setCurrentTransactionName(java.lang.String), setCurrentTransactionReadOnly(boolean), setCurrentTransactionIsolationLevel(java.lang.Integer), setActualTransactionActive(boolean)