com.sun.jdo.spi.persistence.support.sqlstore.impl

Class TransactionImpl

java.lang.Object

com.sun.jdo.spi.persistence.support.sqlstore.impl.TransactionImpl

All Implemented Interfaces:

Transaction, Synchronization

public class TransactionImpl
extends Object
implements Transaction

The Transaction interface allows operations to be performed against the transaction in the target Transaction object. A Transaction object is created corresponding to each global transaction creation. The Transaction object can be used for resource enlistment, synchronization registration, transaction completion and status query operations. This implementation is completely internal. All externally documented methods are on the Transaction interface. Note on synchronized(this): There are a number of places that calls are made outside the transaction system. For example, Synchronization.beforeCompletion() and XAResource.start(). It is important that no locks are held when these callbacks are made. This requires more state checking up return from these calls, and the methods are careful to check state transitions after release the lock and reacquiring it. Also be careful NOT to call into a lower method with the lock, if that method may call out of the transaction system. Take care if you make methods "synchronized" because: synchronized methodName() is not the same lock as a more localized: synchronized(this) This is tested in the regression tests (see "Lock Test")

Field Summary

Fields

Modifier and Type	Field and Description
static int	BMT_JDO
static int	BMT_UT
static int	CMT
static int	NON_MGD Possible values of txType
static int	TRAN_DEFAULT_TIMEOUT
static int	TRAN_MAX_THREADS

Constructor Summary

Constructors

Constructor and Description
TransactionImpl(PersistenceManager pm, String username, char[] password, int seconds) Constructor

Method Summary

Modifier and Type	Method and Description
void	afterCompletion(int st) Called in the managed environment only for transaction completion
void	beforeCompletion() Called in the managed environment only for transaction completion
void	begin() Begin a transaction.
void	begin(Transaction t) Begin a transaction in managed environment
void	commit() Commit the transaction represented by this Transaction object
Connection	getConnection() Returns a Connection.
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() Returns PersistenceManager associated with this transaction
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.
int	getStatus() Obtain the status of this transaction object.
Synchronization	getSynchronization() The user-specified Synchronization instance for this Transaction instance.
int	getTransactionType()
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	releaseConnection() Close a connection.
void	replaceConnection() Replace a connection.
void	rollback() Rollback the transaction represented by this transaction object.
void	setNontransactionalRead(boolean flag) If this flag is set to true, then queries and navigation are allowed without an active transaction
void	setOptimistic(boolean flag) Optimistic transactions do not hold data store locks until commit time.
void	setPersistenceManager(PersistenceManager pm) Set PersistenceManager
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 flag) If true, at rollback instances restore their values and the instances transition to persistent-nontransactional.
void	setRetainValues(boolean flag) If true, at commit instances retain their values and the instances transition to persistent-nontransactional.
void	setRollbackOnly() Modify the transaction object such that the only possible outcome of the transaction is to roll back.
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
static String	statusString(int status) Translates a javax.transaction.Status value into a string.
String	toString() Returns a string representation of this transaction object.
boolean	verify(String username, char[] password) Verify that username and password are equal to ones stored before

Methods inherited from class java.lang.Object

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

Field Detail

TRAN_DEFAULT_TIMEOUT

public static final int TRAN_DEFAULT_TIMEOUT

See Also:

Constant Field Values

TRAN_MAX_THREADS

public static final int TRAN_MAX_THREADS

See Also:

Constant Field Values

NON_MGD

public static final int NON_MGD

Possible values of txType

See Also:

Constant Field Values

CMT

public static final int CMT

See Also:

Constant Field Values

BMT_UT

public static final int BMT_UT

See Also:

Constant Field Values

BMT_JDO

public static final int BMT_JDO

See Also:

Constant Field Values

Constructor Detail

TransactionImpl

public TransactionImpl(PersistenceManager pm,
                       String username,
                       char[] password,
                       int seconds)

Constructor

Method Detail

setPersistenceManager

public void setPersistenceManager(PersistenceManager pm)

Set PersistenceManager

getPersistenceManager

public PersistenceManager getPersistenceManager()

Returns PersistenceManager associated with this transaction

Specified by:

getPersistenceManager in interface Transaction

Returns:

the PersistenceManager for this Transaction instance

isActive

public boolean isActive()

Description copied from interface: Transaction

Returns whether there is a transaction currently active.

Specified by:

isActive in interface Transaction

Returns:

boolean

setRetainValues

public void setRetainValues(boolean flag)

Description copied from interface: Transaction

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

Setting this flag also sets the NontransactionalRead flag.

Specified by:

setRetainValues in interface Transaction

Parameters:

flag - the value of the retainValues property

getRetainValues

public boolean getRetainValues()

Description copied from interface: Transaction

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

Specified by:

getRetainValues in interface Transaction

Returns:

the value of the retainValues property

setRestoreValues

public void setRestoreValues(boolean flag)

Description copied from interface: Transaction

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

Specified by:

setRestoreValues in interface Transaction

Parameters:

flag - the value of the restoreValues property

getRestoreValues

public boolean getRestoreValues()

Description copied from interface: Transaction

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

Specified by:

getRestoreValues in interface Transaction

Returns:

the value of the restoreValues property

setNontransactionalRead

public void setNontransactionalRead(boolean flag)

Description copied from interface: Transaction

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

Specified by:

setNontransactionalRead in interface Transaction

Parameters:

flag - the value of the nontransactionalRead property.

getNontransactionalRead

public boolean getNontransactionalRead()

Description copied from interface: Transaction

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

Specified by:

getNontransactionalRead in interface Transaction

Returns:

the value of the nontransactionalRead property.

setQueryTimeout

public 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

Specified by:

setQueryTimeout in interface Transaction

Parameters:

timeout - new timout value in seconds; zero means unlimited

getQueryTimeout

public int getQueryTimeout()

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

Specified by:

getQueryTimeout in interface Transaction

Returns:

timout value in seconds; zero means unlimited

setUpdateTimeout

public 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

Specified by:

setUpdateTimeout in interface Transaction

Parameters:

timeout - new timout value in seconds; zero means unlimited

getUpdateTimeout

public int getUpdateTimeout()

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

Specified by:

getUpdateTimeout in interface Transaction

Returns:

timout value in seconds; zero means unlimited

setOptimistic

public void setOptimistic(boolean flag)

Description copied from interface: Transaction

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

Specified by:

setOptimistic in interface Transaction

Parameters:

flag - the value of the Optimistic flag.

getOptimistic

public boolean getOptimistic()

Description copied from interface: Transaction

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

Specified by:

getOptimistic in interface Transaction

Returns:

the value of the Optimistic property.

setSynchronization

public void setSynchronization(Synchronization sync)

Description copied from interface: Transaction

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.

Specified by:

setSynchronization in interface Transaction

Parameters:

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

getSynchronization

public Synchronization getSynchronization()

Description copied from interface: Transaction

The user-specified Synchronization instance for this Transaction instance.

Specified by:

getSynchronization in interface Transaction

Returns:

the user-specified Synchronization instance.

getTransactionType

public int getTransactionType()

verify

public boolean verify(String username,
                      char[] password)

Verify that username and password are equal to ones stored before

Parameters:

username - as String

password - as String

Returns:

true if they are equal

begin

public void begin()

Begin a transaction.

Specified by:

begin in interface Transaction

See Also:

Transaction.setOptimistic(boolean), Transaction.getOptimistic()

begin

public void begin(Transaction t)

Begin a transaction in managed environment

commit

public void commit()

Commit the transaction represented by this Transaction object

Specified by:

commit in interface Transaction

beforeCompletion

public void beforeCompletion()

Called in the managed environment only for transaction completion

Specified by:

beforeCompletion in interface Synchronization

afterCompletion

public void afterCompletion(int st)

Called in the managed environment only for transaction completion

Specified by:

afterCompletion in interface Synchronization

rollback

public void rollback()

Rollback the transaction represented by this transaction object.

Specified by:

rollback in interface Transaction

setRollbackOnly

public void setRollbackOnly()

Modify the transaction object such that the only possible outcome of the transaction is to roll back.

getStatus

public int getStatus()

Obtain the status of this transaction object.

Returns:

The transaction status.

statusString

public static String statusString(int status)

Translates a javax.transaction.Status value into a string.

Parameters:

status - Status object to translate.

Returns:

Printable String for a Status object.

getConnection

public Connection getConnection()

Returns a Connection. If there is no existing one, asks ConnectionFactory for a new Connection

replaceConnection

public void replaceConnection()

Replace a connection. Used in a managed environment only. In a J2EE RI Connection need to be replaced at the beforeCompletion.

releaseConnection

public void releaseConnection()

Close a connection. Connection cannot be closed if it is part of the commit/rollback operation or inside a pessimistic transaction

toString

public String toString()

Returns a string representation of this transaction object.

Overrides:

toString in class Object

Returns:

String describing contents of this Transaction object.