org.mbs.services.transaction
Interface TransactionContext

All Known Subinterfaces:

Transaction

public interface TransactionContext

The TransactionContext provides methods, that allows the Transaction Resources to join and participate in the current transaction. It also prevents them from performing full commit or rollback.

Author:

Valentin Valchev

Field Summary

static int	STATUS_ACTIVE Directly after it is created the status is ACTIVE.
static int	STATUS_COMMITTED After the transaction is ended and has ended successfully.
static int	STATUS_COMMITTING During the second phase
static int	STATUS_MARKED_ROLLBACK Any participant of the transaction can mark the transaction setRollbackOnly.
static int	STATUS_NO_TRANSACTION No transaction is currently associated with the target object.
static int	STATUS_PREPARED After the first phase of 2-phase commit, just before STATUS_COMMITTING
static int	STATUS_PREPARING During the first phase of the 2-phase commit.
static int	STATUS_ROLLEDBACK After the transaction is rolled back.
static int	STATUS_ROLLING_BACK During the roll back phase.
static int	STATUS_UNKNOWN A transaction is associated with the target object but its current status cannot be determined.

Method Summary

boolean	associateThread(java.lang.Thread thread) This method allows a resource to associate the current transaction to another thread.
boolean	disassociateThread() This method disassociates the current thread from the transaction.
long	getPid() This method is used to query the PID of the transaction.
int	getStatus() Obtain the status of the transaction associated with the current thread.
boolean	join(TransactionResource tr) A resource manager that wants to participate in the transaction should register with this transaction through this method.
void	resetTimeout() This method will reset the timeout.
void	setRollbackOnly() Modify the transaction associated with the current thread such that the only possible outcome of the transaction is to roll back the transaction.
boolean	waitThreadsToFinish(int timeout) This method waits all threads except one to disassociate from the transaction.

Field Detail

STATUS_UNKNOWN

static final int STATUS_UNKNOWN

A transaction is associated with the target object but its current status cannot be determined. This is a transient condition and a subsequent invocation will ultimately return a different status.

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Constant Field Values

STATUS_ACTIVE

static final int STATUS_ACTIVE

Directly after it is created the status is ACTIVE.

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Constant Field Values

STATUS_COMMITTING

static final int STATUS_COMMITTING

During the second phase

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Constant Field Values

STATUS_COMMITTED

static final int STATUS_COMMITTED

After the transaction is ended and has ended successfully.

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Constant Field Values

STATUS_MARKED_ROLLBACK

static final int STATUS_MARKED_ROLLBACK

Any participant of the transaction can mark the transaction setRollbackOnly. Once this is set, the transaction may continue but a final commit will become a roll-back. The setRollbackOnly method will set the status to STATUS_MARKED_ROLLBACK.

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Constant Field Values

STATUS_NO_TRANSACTION

static final int STATUS_NO_TRANSACTION

No transaction is currently associated with the target object. This will occur after a transaction has completed.

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Constant Field Values

STATUS_PREPARED

static final int STATUS_PREPARED

After the first phase of 2-phase commit, just before STATUS_COMMITTING

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Constant Field Values

STATUS_PREPARING

static final int STATUS_PREPARING

During the first phase of the 2-phase commit.

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Constant Field Values

STATUS_ROLLEDBACK

static final int STATUS_ROLLEDBACK

After the transaction is rolled back. This is a final state, no more changes are possible.

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Constant Field Values

STATUS_ROLLING_BACK

static final int STATUS_ROLLING_BACK

During the roll back phase.

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Constant Field Values

Method Detail

getStatus

int getStatus()

Obtain the status of the transaction associated with the current thread.

Returns:

the status of the transaction

setRollbackOnly

void setRollbackOnly()

Modify the transaction associated with the current thread such that the only possible outcome of the transaction is to roll back the transaction.

join

boolean join(TransactionResource tr)

A resource manager that wants to participate in the transaction should register with this transaction through this method.

Parameters:

tr - The associated transaction resource manager

Returns:

true if this is the first time, or false if it is already registered

resetTimeout

void resetTimeout()

This method will reset the timeout. This is a little bit like a watch-dog, that will prevent transactions from being locked. The creator of the transaction sets the maximum timeout, allowed for a step to execute. When step is executed, it resets the timeout.

getPid

long getPid()

This method is used to query the PID of the transaction.

Returns:

the transaction PID.

associateThread

boolean associateThread(java.lang.Thread thread)
                        throws TransactionException

This method allows a resource to associate the current transaction to another thread. Notice, that this will not unbind the transaction from the current tread.

Parameters:

thread - the thread, to which the transaction should be associated.

Returns:

true if association is succesfull or false if the target thread, already has an associated transaction.

Throws:

TransactionException - If the transaction is not in the active state

disassociateThread

boolean disassociateThread()

This method disassociates the current thread from the transaction.

Returns:

true if the thread was associated to the transaction, false - if not.

waitThreadsToFinish

boolean waitThreadsToFinish(int timeout)

This method waits all threads except one to disassociate from the transaction.

Parameters:

timeout - the timeout within the threads must disassociate in milliseconds.

Returns:

true if the threads disassociated within the given timeout, false - if not.