Package wt.pom

Class Transaction

java.lang.Object

wt.pom.Transaction

public class Transaction
extends Object

Transaction provides interfaces to create transaction blocks. This class supports transaction block nesting. A new database level transaction is not started for nested transaction blocks. Internal state is maintained so that only a commit at the outer most transaction block will cause a database level commit. A rollback at any level will cause the entire transaction to be rolled back immediately.

TransactionListeners can be added within a global or local scope. For global listeners, callback methods will be executed when the outer-most Transaction either commits or rolls back. For the local listeners, the methods will be called when this Transaction instance either commits or rolls back. The overall transactional behavior is not affected.

Supported API: true
Extendable: false

See Also:

• TransactionListener

Field Summary

Fields

Modifier and Type	Field	Description
static final int	DEFAULT_LISTENER_ORDER	This constant specifies the default order used for TransactionListeners.

Constructor Summary

Constructors

Constructor	Description
Transaction()	This constructor initializes the instance.
Transaction(LocalizableMessage a_description)	This constructor initializes the instance.

Method Summary

Modifier and Type	Method	Description
void	addLocalTransactionListener(TransactionListener a_listener)	Add a listener for local Transaction events.
static void	addTransactionListener(TransactionListener listener)	Add a listener for Transaction events.
static void	addTransactionListener(TransactionListener listener, int order)	Add a listener for Transaction events.
void	commit()	Commit a transaction block.
static boolean	containsKeyInContext(Object a_key, boolean a_includeGlobalMap, boolean a_includeMethodContext)	Indicates if the key exists in the current context of the Transaction.
static List	findAllInContext(Object a_key)	Returns List of Transactions that contains the specified key.
static Transaction	findInContext(Object a_key)	Returns the inner-most Transaction in the current Transaction stack that contains the specified key.
static Transaction	getCurrentTransaction()	Returns the current Transaction.
LocalizableMessage	getDescription()	Returns the transaction description.
static Map	getGlobalMap()	Returns the global transaction map.
static Object	getInContext(Object a_key, boolean a_includeGlobalMap, boolean a_includeMethodContext)	Returns the values associated with the specified key exists in the current context of the Transaction.
Map	getLocalMap()	Returns the local transaction map.
static Map	getSharedMap()	Get a Map associated with a shared transaction that may execute across several concurrent threads.
static List	getTransactionStack()	Returns the current Transaction stack.
boolean	hasLocalMap()	Indicates if the Transaction has a local map.
boolean	isShared()	This method indicates if the transaction is shared with other MethodContext threads.
void	removeLocalTransactionListener(TransactionListener listener)	Remove a listener for Transaction events.
static void	removeTransactionListener(TransactionListener listener)	Remove a listener for Transaction events.
void	rollback()	Rollback a transaction block.
void	start()	Start a transaction block.
boolean	supportsSavepoints()	This method indicates if Savepoints can be used for the transaction.

Methods inherited from class java.lang.Object

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

Field Details

DEFAULT_LISTENER_ORDER

public static final int DEFAULT_LISTENER_ORDER

This constant specifies the default order used for TransactionListeners.

Supported API: true

See Also:

• Constant Field Values

Constructor Details

Transaction

public Transaction()

This constructor initializes the instance.

Supported API: true

Transaction

public Transaction(LocalizableMessage a_description)
            throws PersistenceException

This constructor initializes the instance.

Parameters:

a_description - localizable message describing this transaction. The object must implement Evolvable.

Supported API: true

Throws:

PersistenceException

See Also:

• Evolvable

Method Details

getSharedMap

public static Map getSharedMap()
                        throws WTException

Get a Map associated with a shared transaction that may execute across several concurrent threads. The Map returned by this method will be thread safe if the transaction is shared by more than one thread. The keys and values stored in this map may not be thread safe so any code that accesses the contents of this map must do so in a thread safe manner.

Returns:

Map

Supported API: true

Throws:

WTException

isShared

public boolean isShared()
                 throws WTException

This method indicates if the transaction is shared with other MethodContext threads.

Returns:

true, if the transaction is shared

Supported API: true

Throws:

WTException

supportsSavepoints

public boolean supportsSavepoints()
                           throws WTException

This method indicates if Savepoints can be used for the transaction.

Returns:

true, if savepoints can be used

Supported API: true

Throws:

WTException

containsKeyInContext

public static boolean containsKeyInContext(Object a_key,
 boolean a_includeGlobalMap,
 boolean a_includeMethodContext)
                                    throws WTException

Indicates if the key exists in the current context of the Transaction. The context includes the Transaction stack local Maps and optionally the global Transaction Map and MethodContext.

Supported API: true

Throws:

WTException

getInContext

public static Object getInContext(Object a_key,
 boolean a_includeGlobalMap,
 boolean a_includeMethodContext)
                           throws WTException

Returns the values associated with the specified key exists in the current context of the Transaction. The context includes the Transaction stack local Maps and optionally the global Transaction Map and MethodContext. The key is searched in the current Transaction context local Maps from inner (most recently created) to outer (first created) Transaction blocks. If the key is not found in the Transaction context and a_includeGlobalMap is true, then the Transaction global map is searched. If still not found and a_includeMethodContext is true, then the MethodContext is searched.

Returns:

the value associated with the key, null if not found

Supported API: true

Throws:

WTException

findInContext

public static Transaction findInContext(Object a_key)
                                 throws WTException

Returns the inner-most Transaction in the current Transaction stack that contains the specified key.

Returns:

current local Transaction that contains the key or null if no Transaction exists or the key is not found.

Supported API: true

Throws:

WTException

findAllInContext

public static List findAllInContext(Object a_key)
                             throws WTException

Returns List of Transactions that contains the specified key. The List is ordered from inner-most (index=0) to outer-most (index=size() - 1).

Returns:

List of local Transactions that contain the key or null if no Transaction exists or the key is not found.

Supported API: true

Throws:

WTException

getTransactionStack

public static List getTransactionStack()
                                throws WTException

Returns the current Transaction stack.

Returns:

current Transaction stack or null if no Transaction exists.

Supported API: true

Throws:

WTException

getCurrentTransaction

public static Transaction getCurrentTransaction()
                                         throws WTException

Returns the current Transaction.

Returns:

current local Transaction or null if no Transaction exists.

Supported API: true

Throws:

WTException

getGlobalMap

public static Map getGlobalMap()
                        throws WTException

Returns the global transaction map. If a global Map does not currently exist, then one is created.

Returns:

global Transaction Map

Supported API: true

Throws:

WTException

addTransactionListener

public static void addTransactionListener(TransactionListener listener)
                                   throws PersistenceException

Add a listener for Transaction events. The listener is added with the default relative ordering. The listeners will be called in the relative order with other listeners from lowest to highest.

Parameters:

listener - to add

Supported API: true

Throws:

PersistenceException

addTransactionListener

public static void addTransactionListener(TransactionListener listener,
 int order)
                                   throws PersistenceException

Add a listener for Transaction events. The listener is added with the specified relative ordering. The listeners will be called in the relative order with other listeners from lowest to highest.

Parameters:

listener - to add

order - relative to other listeners

Supported API: true

Throws:

PersistenceException

removeTransactionListener

public static void removeTransactionListener(TransactionListener listener)
                                      throws PersistenceException

Remove a listener for Transaction events.

Parameters:

listener - to remove

Supported API: true

Throws:

PersistenceException

getDescription

public LocalizableMessage getDescription()

Returns the transaction description.

Supported API: true

hasLocalMap

public boolean hasLocalMap()

Indicates if the Transaction has a local map.

Supported API: true

getLocalMap

public Map getLocalMap()

Returns the local transaction map. If a local Map does not currently exist, then one is created.

Supported API: true

start

public void start()
           throws PersistenceException

Start a transaction block.

Supported API: true

Throws:

PersistenceException

commit

public void commit()
            throws PersistenceException

Commit a transaction block. An acutal database commit is only performed when the outer-most transaction block is committed.

Supported API: true

Throws:

PersistenceException

rollback

public void rollback()

Rollback a transaction block.

Supported API: true

addLocalTransactionListener

public void addLocalTransactionListener(TransactionListener a_listener)
                                 throws PersistenceException

Add a listener for local Transaction events.

Supported API: true

Throws:

PersistenceException

removeLocalTransactionListener

public void removeLocalTransactionListener(TransactionListener listener)
                                    throws PersistenceException

Remove a listener for Transaction events.

Supported API: true

Throws:

PersistenceException