com.antelmann.db
Class AbstractDBTransaction

java.lang.Object
  com.antelmann.db.AbstractDBTransaction

All Implemented Interfaces:

DBTransaction

Direct Known Subclasses:

SQLTransaction

public abstract class AbstractDBTransaction
extends Object
implements DBTransaction

a simple base implementation for a DBTransaction. By implementing the abstract methods (instead of those that implement the interface and are marked final), the listeners are handled transparently.

Since:

17. November 2006, 19:24

Author:

Holger Antelmann

Field Summary

protected Database<?>

database

Constructor Summary

AbstractDBTransaction(Database<?> database)

Method Summary

void	abort() aborts this transaction; requires ownership of this instance.
boolean	addTransactionListener(TransactionListener listener)
void	begin() sets the transaction to active and allows access to the Resources provided that the calling thread holds the lock on this instance.
void	commit() commits all data within the transaction scope to the underlying database; requires ownership of this instance.
protected abstract void	doAbort()
protected abstract void	doBegin()
protected abstract void	doCommit()
Database<?>	getDatabase() gives access to the associated Database
TransactionListener[]	getTransactionListeners()
boolean	isActive() if true, a transaction is currently in progress and has not been committed or aborted, yet.
boolean	isReadOnly() informs whether the currently running transaction is configured to be read-only.
boolean	removeTransactionListener(TransactionListener listener)
void	setNextToReadOnly(boolean flag) allows to configure the next transaction to be read-only.

Methods inherited from class java.lang.Object

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

Field Detail

database

protected Database<?> database

Constructor Detail

AbstractDBTransaction

public AbstractDBTransaction(Database<?> database)

Method Detail

addTransactionListener

public boolean addTransactionListener(TransactionListener listener)

Specified by:

addTransactionListener in interface DBTransaction

removeTransactionListener

public boolean removeTransactionListener(TransactionListener listener)

Specified by:

removeTransactionListener in interface DBTransaction

getTransactionListeners

public TransactionListener[] getTransactionListeners()

Specified by:

getTransactionListeners in interface DBTransaction

getDatabase

public Database<?> getDatabase()

Description copied from interface: DBTransaction

gives access to the associated Database

Specified by:

getDatabase in interface DBTransaction

doBegin

protected abstract void doBegin()
                         throws TransactionException

Throws:

TransactionException

doCommit

protected abstract void doCommit()
                          throws DatabaseException

Throws:

DatabaseException

doAbort

protected abstract void doAbort()
                         throws DatabaseException

Throws:

DatabaseException

begin

public final void begin()
                 throws TransactionException

Description copied from interface: DBTransaction

sets the transaction to active and allows access to the Resources provided that the calling thread holds the lock on this instance.

Specified by:

begin in interface DBTransaction

Throws:

TransactionException - if the transaction is already active or if the transaction is in transition

See Also:

TransactionListener.transactionAborted(DBTransaction), TransactionListener.transactionCommitted(DBTransaction)

commit

public final void commit()
                  throws TransactionException,
                         DatabaseException

Description copied from interface: DBTransaction

commits all data within the transaction scope to the underlying database; requires ownership of this instance.

Specified by:

commit in interface DBTransaction

Throws:

TransactionException - if the transaction is already active

DatabaseException - if the transaction could not be committed to the underlying service

abort

public final void abort()
                 throws TransactionException,
                        DatabaseException

Description copied from interface: DBTransaction

aborts this transaction; requires ownership of this instance.

Specified by:

abort in interface DBTransaction

Throws:

TransactionException - if the transaction is already active

DatabaseException - if the transaction could not be aborted from the underlying service

isActive

public boolean isActive()

Description copied from interface: DBTransaction

if true, a transaction is currently in progress and has not been committed or aborted, yet. Access to resources is only save if this method returns true and the calling thread holds the lock on this instance. In order to rely on the return value after the method returns, an ownership of the calling thread on this DBTransaction is required.

Specified by:

isActive in interface DBTransaction

isReadOnly

public boolean isReadOnly()

Description copied from interface: DBTransaction

informs whether the currently running transaction is configured to be read-only. If there is no active transaction, the return value will determine whether the next transaction to be started is going to be read-only. This setting only applies for the current/next transaction, not for subsequent ones. Some given database implementation may, however, configure every transaction to be read-only (or read-write) while altering this setting may not be supported. DBTransaction.setNextToReadOnly(boolean)

Specified by:

isReadOnly in interface DBTransaction

setNextToReadOnly

public void setNextToReadOnly(boolean flag)
                       throws TransactionException,
                              UnsupportedOperationException

Description copied from interface: DBTransaction

allows to configure the next transaction to be read-only. This call must be repeated before every transaction that is to be read-only, as after each commit/abort this setting is reset to false.

Specified by:

setNextToReadOnly in interface DBTransaction

Parameters:

flag - if true, the next transaction will run read-only; if false, the next transaction will be read-write

Throws:

TransactionException - if a transaction is currently active

UnsupportedOperationException

See Also:

DBTransaction.isReadOnly()