com.sun.jdo.api.persistence.support
Interface Transaction

public interface Transaction

The JDO Transaction interface is a sub-interface of the PersistenceManager that deals with options and completion of transactions under user control.

Transaction options include whether optimistic concurrency control should be used for the current transaction, and whether values should be retained in JDO instances after transaction completion.

Transaction completion methods have the same semantics as javax.transaction UserTransaction, and are valid only in the non-managed, non-distributed transaction environment.

Version:

0.1

Author:

Craig Russell

Method Summary

void	begin() Begin a transaction.
void	commit() Commit the current transaction.
boolean	getNontransactionalRead() If this flag is set to true, then queries and navigation are allowed without an active transaction
boolean	getOptimistic() Optimistic transactions do not hold data store locks until commit time.
PersistenceManager	getPersistenceManager() The Tranansaction instance is always associated with exactly one PersistenceManager.
int	getQueryTimeout() Gets the number of seconds to wait for a query statement to execute in the datastore associated with this Transaction instance
boolean	getRestoreValues() If true, at rollback time instances restore their field values.
boolean	getRetainValues() If true, at commit time instances retain their field values.
Synchronization	getSynchronization() The user-specified Synchronization instance for this Transaction instance.
int	getUpdateTimeout() Gets the number of seconds to wait for an update statement to execute in the datastore associated with this Transaction instance
boolean	isActive() Returns whether there is a transaction currently active.
void	rollback() Roll back the current transaction.
void	setNontransactionalRead(boolean flag) If this flag is set to true, then queries and navigation are allowed without an active transaction
void	setOptimistic(boolean optimistic) Optimistic transactions do not hold data store locks until commit time.
void	setQueryTimeout(int timeout) Sets the number of seconds to wait for a query statement to execute in the datastore associated with this Transaction instance
void	setRestoreValues(boolean restoreValues) If true, at rollback instances restore their values and the instances transition to persistent-nontransactional.
void	setRetainValues(boolean retainValues) If true, at commit instances retain their values and the instances transition to persistent-nontransactional.
void	setSynchronization(Synchronization sync) The user can specify a Synchronization instance to be notified on transaction completions.
void	setUpdateTimeout(int timeout) Sets the number of seconds to wait for an update statement to execute in the datastore associated with this Transaction instance

Method Detail

begin

void begin()

Begin a transaction. The type of transaction is determined by the setting of the Optimistic flag.

Throws:

JDOUserException - if a distributed transaction XAResource is assigned to this Transaction

See Also:

setOptimistic(boolean), getOptimistic()

commit

void commit()

Commit the current transaction.

rollback

void rollback()

Roll back the current transaction.

isActive

boolean isActive()

Returns whether there is a transaction currently active.

Returns:

boolean

setRetainValues

void setRetainValues(boolean retainValues)

If true, at commit instances retain their values and the instances transition to persistent-nontransactional.

Setting this flag also sets the NontransactionalRead flag.

Parameters:

retainValues - the value of the retainValues property

getRetainValues

boolean getRetainValues()

If true, at commit time instances retain their field values.

Returns:

the value of the retainValues property

setRestoreValues

void setRestoreValues(boolean restoreValues)

If true, at rollback instances restore their values and the instances transition to persistent-nontransactional.

Parameters:

restoreValues - the value of the restoreValues property

getRestoreValues

boolean getRestoreValues()

If true, at rollback time instances restore their field values.

Returns:

the value of the restoreValues property

setOptimistic

void setOptimistic(boolean optimistic)

Optimistic transactions do not hold data store locks until commit time.

Parameters:

optimistic - the value of the Optimistic flag.

getOptimistic

boolean getOptimistic()

Optimistic transactions do not hold data store locks until commit time.

Returns:

the value of the Optimistic property.

setNontransactionalRead

void setNontransactionalRead(boolean flag)

If this flag is set to true, then queries and navigation are allowed without an active transaction

Parameters:

flag - the value of the nontransactionalRead property.

getNontransactionalRead

boolean getNontransactionalRead()

If this flag is set to true, then queries and navigation are allowed without an active transaction

Returns:

the value of the nontransactionalRead property.

setSynchronization

void setSynchronization(Synchronization sync)

The user can specify a Synchronization instance to be notified on transaction completions. The beforeCompletion method is called prior to flushing instances to the data store.

The afterCompletion method is called after performing the data store commit operation.

Parameters:

sync - the Synchronization instance to be notified; null for none

getSynchronization

Synchronization getSynchronization()

The user-specified Synchronization instance for this Transaction instance.

Returns:

the user-specified Synchronization instance.

setQueryTimeout

void setQueryTimeout(int timeout)

Sets the number of seconds to wait for a query statement to execute in the datastore associated with this Transaction instance

Parameters:

timeout - new timout value in seconds; zero means unlimited

getQueryTimeout

int getQueryTimeout()

Gets the number of seconds to wait for a query statement to execute in the datastore associated with this Transaction instance

Returns:

timout value in seconds; zero means unlimited

setUpdateTimeout

void setUpdateTimeout(int timeout)

Sets the number of seconds to wait for an update statement to execute in the datastore associated with this Transaction instance

Parameters:

timeout - new timout value in seconds; zero means unlimited

getUpdateTimeout

int getUpdateTimeout()

Gets the number of seconds to wait for an update statement to execute in the datastore associated with this Transaction instance

Returns:

timout value in seconds; zero means unlimited

getPersistenceManager

PersistenceManager getPersistenceManager()

The Tranansaction instance is always associated with exactly one PersistenceManager.

Returns:

the PersistenceManager for this Transaction instance