org.apache.ojb.odmg
Class NarrowTransaction

java.lang.Object
  org.apache.ojb.odmg.NarrowTransaction

All Implemented Interfaces:

HasBroker, TransactionExt, Transaction

public class NarrowTransaction
extends Object
implements TransactionExt

Wraps Transaction in managed environments.

Author:

Armin Waibel

Field Summary

Fields inherited from interface org.odmg.Transaction

READ, UPGRADE, WRITE

Constructor Summary

NarrowTransaction(TransactionImpl tx)

Method Summary

void	abort() Abort the underlying odmg-transaction
void	begin() Not supported!!
void	checkpoint() Not supported!!
void	commit() Not supported!!
void	flush() Calling flush flushes persistent object modifications made within the ODMG transaction since the last checkpoint to the underlying database transaction, but does commit the database transaction.
PersistenceBroker	getBroker() Return associated PB instance, or null if not found.
Object	getObjectByIdentity(Identity id)
TransactionImpl	getRealTransaction()
boolean	isDeleted(Identity id) Checks if the object with the given Identity has been deleted within the transaction using Database.deletePersistent(Object) or TransactionExt.markDelete(Object).
boolean	isImplicitLocking() Returns true if implicite locking is enabled.
boolean	isOpen() Not supported!!
boolean	isOrdering() Return true if the OJB ordering algorithm is enabled.
void	join() Not supported!!
void	leave() Not supported!!
void	lock(Object obj, int lockMode) lock the given object
void	markDelete(Object anObject) Marks an object for deletion without locking the object.
void	markDirty(Object anObject) Marks an object as dirty without locking the object.
void	setCascadingDelete(Class target, boolean doCascade) Allows to change the cascading delete behavior of all references of the specified class while this transaction is in use.
void	setCascadingDelete(Class target, String referenceField, boolean doCascade) Allows to change the cascading delete behavior of the target class's reference field while this transaction is in use.
void	setImplicitLocking(boolean value) This method can be used to activate or deactivate the implicit locking mechanism for the current transaction.
void	setOrdering(boolean ordering) Allows to enable/disable the OJB persistent object ordering algorithm.
boolean	tryLock(Object obj, int lockMode) lock the given object if possible

Methods inherited from class java.lang.Object

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

Constructor Detail

NarrowTransaction

public NarrowTransaction(TransactionImpl tx)

Method Detail

getRealTransaction

public TransactionImpl getRealTransaction()

markDelete

public void markDelete(Object anObject)

Description copied from interface: TransactionExt

Marks an object for deletion without locking the object. If the object wasn't locked before, OJB will ask for a WRITE lock at commit.

Specified by:

markDelete in interface TransactionExt

Parameters:

anObject - Object to be marked

markDirty

public void markDirty(Object anObject)

Description copied from interface: TransactionExt

Marks an object as dirty without locking the object. If the object wasn't locked before, OJB will ask for a WRITE lock at commit.

Specified by:

markDirty in interface TransactionExt

Parameters:

anObject - Object to be marked

flush

public void flush()

Description copied from interface: TransactionExt

Calling flush flushes persistent object modifications made within the ODMG transaction since the last checkpoint to the underlying database transaction, but does commit the database transaction. The ODMG transaction retains all locks it held on those objects at the time the flush was invoked.

This method is very similair to Transaction.checkpoint().

Specified by:

flush in interface TransactionExt

getBroker

public PersistenceBroker getBroker()

Return associated PB instance, or null if not found.

Specified by:

getBroker in interface HasBroker

join

public void join()

Not supported!!

Specified by:

join in interface Transaction

leave

public void leave()

Not supported!!

Specified by:

leave in interface Transaction

begin

public void begin()

Not supported!!

Specified by:

begin in interface Transaction

isOpen

public boolean isOpen()

Not supported!!

Specified by:

isOpen in interface Transaction

Returns:

True if the transaction is open, otherwise false.

commit

public void commit()

Not supported!!

Specified by:

commit in interface Transaction

abort

public void abort()

Abort the underlying odmg-transaction

Specified by:

abort in interface Transaction

checkpoint

public void checkpoint()

Not supported!!

Specified by:

checkpoint in interface Transaction

lock

public void lock(Object obj,
                 int lockMode)
          throws LockNotGrantedException

lock the given object

Specified by:

lock in interface Transaction

Parameters:

obj - The object to acquire a lock on.

lockMode - The lock mode to acquire. The lock modes are READ, UPGRADE, and WRITE.

Throws:

LockNotGrantedException - Is thrown if the given lock mode could not be acquired.

See Also:

Transaction.lock(java.lang.Object, int)

tryLock

public boolean tryLock(Object obj,
                       int lockMode)

lock the given object if possible

Specified by:

tryLock in interface Transaction

Parameters:

obj - The object to acquire a lock on.

lockMode - The lock mode to acquire. The lock modes are READ, UPGRADE, and WRITE.

Returns:

True if the lock has been acquired, otherwise false.

See Also:

Transaction.tryLock(java.lang.Object, int)

getObjectByIdentity

public Object getObjectByIdentity(Identity id)
                           throws PersistenceBrokerException

Throws:

PersistenceBrokerException

setImplicitLocking

public void setImplicitLocking(boolean value)

Description copied from interface: TransactionExt

This method can be used to activate or deactivate the implicit locking mechanism for the current transaction.
If set true OJB implicitly locks objects to ODMG transactions after performing OQL queries. Also if implicit locking is used locking objects is recursive, that is associated objects are also locked. If ImplicitLocking is set to 'false', no locks are obtained in OQL queries, lookup objects and there is also no recursive locking.

Turning off implicit locking may improve performance but requires additional care to make sure all changed objects are properly registered to the transaction.

Specified by:

setImplicitLocking in interface TransactionExt

Parameters:

value - If set true implicit locking is enabled, if false, implicit locking is disabled.

See Also:

TransactionExt.setImplicitLocking(boolean)

isImplicitLocking

public boolean isImplicitLocking()

Description copied from interface: TransactionExt

Returns true if implicite locking is enabled.

Specified by:

isImplicitLocking in interface TransactionExt

See Also:

TransactionExt.isImplicitLocking()

setCascadingDelete

public void setCascadingDelete(Class target,
                               String referenceField,
                               boolean doCascade)

Description copied from interface: TransactionExt

Allows to change the cascading delete behavior of the target class's reference field while this transaction is in use.

Specified by:

setCascadingDelete in interface TransactionExt

Parameters:

target - The class to change cascading delete behavior of the references.

referenceField - The field name of the 1:1, 1:n or m:n reference.

doCascade - If true cascading delete is enabled, false disabled.

See Also:

TransactionExt.setCascadingDelete(Class, String, boolean)

setCascadingDelete

public void setCascadingDelete(Class target,
                               boolean doCascade)

Description copied from interface: TransactionExt

Allows to change the cascading delete behavior of all references of the specified class while this transaction is in use.

Specified by:

setCascadingDelete in interface TransactionExt

Parameters:

target - The class to change cascading delete behavior of all references.

doCascade - If true cascading delete is enabled, false disabled.

See Also:

TransactionExt.setCascadingDelete(Class, boolean)

isOrdering

public boolean isOrdering()

Description copied from interface: TransactionExt

Return true if the OJB ordering algorithm is enabled.

Specified by:

isOrdering in interface TransactionExt

See Also:

TransactionExt.setOrdering(boolean)

setOrdering

public void setOrdering(boolean ordering)

Description copied from interface: TransactionExt

Allows to enable/disable the OJB persistent object ordering algorithm. If true OJB try to order the modified/new/deleted objects in a correct order (based on a algorithm) before the objects are written to the persistent storage.
If the used databases support 'deferred checks' it's recommended to use this feature and to disable OJB's object ordering.

If false the order of the objects rely on the order specified by the user and on settings like TransactionExt.setImplicitLocking(boolean).

Specified by:

setOrdering in interface TransactionExt

Parameters:

ordering - Set true to enable object ordering on commit.

See Also:

ImplementationExt.setOrdering(boolean)

isDeleted

public boolean isDeleted(Identity id)

Description copied from interface: TransactionExt

Checks if the object with the given Identity has been deleted within the transaction using Database.deletePersistent(Object) or TransactionExt.markDelete(Object).

Specified by:

isDeleted in interface TransactionExt

Parameters:

id - The identity of the object.

Returns:

true if the object has been deleted within the transaction.