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The JDO Transaction
interface provides for initiation and completion
of transactions under user control.
It is a sub-interface of the PersistenceManager
that deals with options and transaction demarcation.
Transaction options include whether optimistic concurrency control should be used for the current transaction, whether instances may hold values in the cache outside transactions, and whether values should be retained in the cache after transaction completion. These options are valid for both managed and non-managed transactions.
Transaction initiation and completion methods have similar semantics to
javax.transaction.UserTransaction
when used outside a managed
environment. When used in a managed environment, transaction initiation
and completion methods may only be used with bean-managed transaction semantics.
Method Summary | |
void |
begin()
Begin a transaction. |
void |
commit()
Commit the current transaction. |
boolean |
getNontransactionalRead()
If true , allows persistent instances to be read without
a transaction active. |
boolean |
getNontransactionalWrite()
If true , allows persistent instances to be written without
a transaction active. |
boolean |
getOptimistic()
Optimistic transactions do not hold data store locks until commit time. |
PersistenceManager |
getPersistenceManager()
The Transaction instance is always associated with exactly one
PersistenceManager . |
boolean |
getRestoreValues()
Return the current value of the restoreValues property. |
boolean |
getRetainValues()
If true , at commit time instances retain their field values. |
boolean |
getRollbackOnly()
Returns the rollback-only status of the transaction. |
javax.transaction.Synchronization |
getSynchronization()
The user-specified Synchronization instance for this Transaction instance. |
boolean |
isActive()
Returns whether there is a transaction currently active. |
void |
rollback()
Roll back the current transaction. |
void |
setNontransactionalRead(boolean nontransactionalRead)
If true , allow persistent instances to be read without
a transaction active.
|
void |
setNontransactionalWrite(boolean nontransactionalWrite)
If true , allow persistent instances to be written without
a transaction active.
|
void |
setOptimistic(boolean optimistic)
Optimistic transactions do not hold data store locks until commit time. |
void |
setRestoreValues(boolean restoreValues)
If true , at rollback, fields of newly persistent instances
are restored to
their values as of the beginning of the transaction, and the instances
revert to transient. |
void |
setRetainValues(boolean retainValues)
If true , at commit instances retain their values and the instances
transition to persistent-nontransactional.
|
void |
setRollbackOnly()
Sets the rollback-only status of the transaction to true .
|
void |
setSynchronization(javax.transaction.Synchronization sync)
The user can specify a Synchronization instance to be notified on
transaction completions. |
Method Detail |
public void begin()
JDOUserException
- if transactions are managed by a container
in the managed environment, or if the transaction is already active.setOptimistic(boolean)
,
getOptimistic()
public void commit()
JDOUserException
- if transactions are managed by a container
in the managed environment, or if the transaction is not active.public void rollback()
JDOUserException
- if transactions are managed by a container
in the managed environment, or if the transaction is not active.public boolean isActive()
true
if the transaction is active.public boolean getRollbackOnly()
true
if the transaction has been
marked for rollback.public void setRollbackOnly()
true
.
After this flag is set to true
, the transaction
can no longer be committed, and any attempt to commit the
transaction will throw JDOUserException.
- Since:
- 2.0
public void setNontransactionalRead(boolean nontransactionalRead)
true
, allow persistent instances to be read without
a transaction active.
If an implementation does not support this option, a
JDOUnsupportedOptionException
is thrown.
nontransactionalRead
- the value of the nontransactionalRead propertypublic boolean getNontransactionalRead()
true
, allows persistent instances to be read without
a transaction active.
public void setNontransactionalWrite(boolean nontransactionalWrite)
true
, allow persistent instances to be written without
a transaction active.
If an implementation does not support this option, a
JDOUnsupportedOptionException
is thrown.
nontransactionalWrite
- the value of the nontransactionalRead propertypublic boolean getNontransactionalWrite()
true
, allows persistent instances to be written without
a transaction active.
public void setRetainValues(boolean retainValues)
true
, at commit instances retain their values and the instances
transition to persistent-nontransactional.
If an implementation does not support this option, a
JDOUnsupportedOptionException
is thrown.
retainValues
- the value of the retainValues propertypublic boolean getRetainValues()
true
, at commit time instances retain their field values.
public void setRestoreValues(boolean restoreValues)
true
, at rollback, fields of newly persistent instances
are restored to
their values as of the beginning of the transaction, and the instances
revert to transient. Additionally, fields of modified
instances of primitive types and immutable reference types
are restored to their values as of the beginning of the
transaction.
If false
, at rollback, the values of fields of
newly persistent instances are unchanged and the instances revert to
transient. Additionally, dirty instances transition to hollow.
If an implementation does not support this option, a
JDOUnsupportedOptionException
is thrown.
restoreValues
- the value of the restoreValues propertypublic boolean getRestoreValues()
public void setOptimistic(boolean optimistic)
JDOUnsupportedOptionException
is thrown.
optimistic
- the value of the Optimistic flag.public boolean getOptimistic()
public void setSynchronization(javax.transaction.Synchronization sync)
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 state
transitions of persistent and transactional instances, following
the data store commit or rollback operation.
Only one Synchronization
instance can be registered with the
Transaction
. If the application requires more than one instance to
receive synchronization callbacks, then the single application instance
is responsible for managing them, and forwarding callbacks to them.
sync
- the Synchronization
instance to be notified; null
for nonepublic javax.transaction.Synchronization getSynchronization()
Synchronization
instance for this Transaction
instance.
Synchronization
instance.public PersistenceManager getPersistenceManager()
Transaction
instance is always associated with exactly one
PersistenceManager
.
PersistenceManager
for this Transaction
instance
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