org.postgresql.xa

Class PGXAConnection

java.lang.Object

org.postgresql.ds.PGPooledConnection

org.postgresql.xa.PGXAConnection

All Implemented Interfaces:

PooledConnection, XAConnection, XAResource

public class PGXAConnection
extends PGPooledConnection
implements XAConnection, XAResource

The PostgreSQL implementation of XAResource.

This implementation doesn't support transaction interleaving (see JTA specification, section 3.4.4) and suspend/resume.

Two-phase commit requires PostgreSQL server version 8.1 or higher.

Author:

Heikki Linnakangas (heikki.linnakangas@iki.fi)

Field Summary

Fields inherited from interface javax.transaction.xa.XAResource

TMENDRSCAN, TMFAIL, TMJOIN, TMNOFLAGS, TMONEPHASE, TMRESUME, TMSTARTRSCAN, TMSUCCESS, TMSUSPEND, XA_OK, XA_RDONLY

Constructor Summary

Constructors

Constructor and Description
PGXAConnection(BaseConnection conn)

Method Summary

Methods

Modifier and Type	Method and Description
void	commit(Xid xid, boolean onePhase)
void	end(Xid xid, int flags) Preconditions:
void	forget(Xid xid) Does nothing, since we don't do heuristics.
Connection	getConnection() XAConnection interface.
int	getTransactionTimeout() We don't do transaction timeouts.
XAResource	getXAResource() Retrieves an XAResource object that the transaction manager will use to manage this XAConnection object's participation in a distributed transaction.
boolean	isSameRM(XAResource xares)
int	prepare(Xid xid) Prepares transaction.
Xid[]	recover(int flag) Recovers transaction.
void	rollback(Xid xid) Preconditions:
boolean	setTransactionTimeout(int seconds) We don't do transaction timeouts.
void	start(Xid xid, int flags) Preconditions:

Methods inherited from class org.postgresql.ds.PGPooledConnection

addConnectionEventListener, addStatementEventListener, close, createConnectionEvent, removeConnectionEventListener, removeStatementEventListener

Methods inherited from class java.lang.Object

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

Methods inherited from interface javax.sql.PooledConnection

addConnectionEventListener, addStatementEventListener, close, removeConnectionEventListener, removeStatementEventListener

Constructor Detail

PGXAConnection

public PGXAConnection(BaseConnection conn)
               throws SQLException

Throws:

SQLException

Method Detail

getConnection

public Connection getConnection()
                         throws SQLException

XAConnection interface.

Specified by:

getConnection in interface PooledConnection

Overrides:

getConnection in class PGPooledConnection

Returns:

a Connection object that is a handle to this PooledConnection object

Throws:

SQLException - if a database access error occurs

getXAResource

public XAResource getXAResource()

Description copied from interface: javax.sql.XAConnection

Retrieves an XAResource object that the transaction manager will use to manage this XAConnection object's participation in a distributed transaction.

Specified by:

getXAResource in interface XAConnection

Returns:

the XAResource object

start

public void start(Xid xid,
         int flags)
           throws XAException

Preconditions:

1. Flags must be one of TMNOFLAGS, TMRESUME or TMJOIN
2. xid != null
3. Connection must not be associated with a transaction
4. The TM hasn't seen the xid before

Implementation deficiency preconditions:

1. TMRESUME not supported.
2. If flags is TMJOIN, we must be in ended state, and xid must be the current transaction
3. Unless flags is TMJOIN, previous transaction using the connection must be committed or prepared or rolled back

Postconditions:

1. Connection is associated with the transaction

Specified by:

start in interface XAResource

Throws:

XAException

end

public void end(Xid xid,
       int flags)
         throws XAException

Preconditions:

1. Flags is one of TMSUCCESS, TMFAIL, TMSUSPEND
2. xid != null
3. Connection is associated with transaction xid

Implementation deficiency preconditions:

1. Flags is not TMSUSPEND

Postconditions:

1. Connection is disassociated from the transaction.

Specified by:

end in interface XAResource

Throws:

XAException

prepare

public int prepare(Xid xid)
            throws XAException

Prepares transaction. Preconditions:

1. xid != null
2. xid is in ended state

Implementation deficiency preconditions:

1. xid was associated with this connection

Postconditions:

1. Transaction is prepared

Specified by:

prepare in interface XAResource

Throws:

XAException

recover

public Xid[] recover(int flag)
              throws XAException

Recovers transaction. Preconditions:

1. flag must be one of TMSTARTRSCAN, TMENDRSCAN, TMNOFLAGS or TMSTARTTRSCAN | TMENDRSCAN
2. If flag isn't TMSTARTRSCAN or TMSTARTRSCAN | TMENDRSCAN, a recovery scan must be in progress

Postconditions:

1. list of prepared xids is returned

Specified by:

recover in interface XAResource

Throws:

XAException

rollback

public void rollback(Xid xid)
              throws XAException

Preconditions:

1. xid is known to the RM or it's in prepared state

Implementation deficiency preconditions:

1. xid must be associated with this connection if it's not in prepared state.

Postconditions:

1. Transaction is rolled back and disassociated from connection

Specified by:

rollback in interface XAResource

Throws:

XAException

commit

public void commit(Xid xid,
          boolean onePhase)
            throws XAException

Specified by:

commit in interface XAResource

Throws:

XAException

isSameRM

public boolean isSameRM(XAResource xares)
                 throws XAException

Specified by:

isSameRM in interface XAResource

Throws:

XAException

forget

public void forget(Xid xid)
            throws XAException

Does nothing, since we don't do heuristics.

Specified by:

forget in interface XAResource

Throws:

XAException

getTransactionTimeout

public int getTransactionTimeout()

We don't do transaction timeouts. Just returns 0.

Specified by:

getTransactionTimeout in interface XAResource

setTransactionTimeout

public boolean setTransactionTimeout(int seconds)

We don't do transaction timeouts. Returns false.

Specified by:

setTransactionTimeout in interface XAResource