org.postgresql.xa

Class PGXAConnection

java.lang.Object

org.postgresql.ds.PGPooledConnection

org.postgresql.xa.PGXAConnection

All Implemented Interfaces:

javax.sql.PooledConnection, javax.sql.XAConnection, javax.transaction.xa.XAResource

public class PGXAConnection
extends PGPooledConnection
implements javax.sql.XAConnection, javax.transaction.xa.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

Modifier and Type	Method and Description
void	commit(javax.transaction.xa.Xid xid, boolean onePhase)
void	end(javax.transaction.xa.Xid xid, int flags) Preconditions: Flags is one of TMSUCCESS, TMFAIL, TMSUSPEND xid != null Connection is associated with transaction xid
void	forget(javax.transaction.xa.Xid xid) Does nothing, since we don't do heuristics.
java.sql.Connection	getConnection() XAConnection interface.
int	getTransactionTimeout() We don't do transaction timeouts.
javax.transaction.xa.XAResource	getXAResource()
boolean	isSameRM(javax.transaction.xa.XAResource xares)
int	prepare(javax.transaction.xa.Xid xid) Prepares transaction.
javax.transaction.xa.Xid[]	recover(int flag) Recovers transaction.
void	rollback(javax.transaction.xa.Xid xid) Preconditions: xid is known to the RM or it's in prepared state
boolean	setTransactionTimeout(int seconds) We don't do transaction timeouts.
void	start(javax.transaction.xa.Xid xid, int flags) Preconditions: Flags must be one of TMNOFLAGS, TMRESUME or TMJOIN xid != null Connection must not be associated with a transaction The TM hasn't seen the xid before

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 java.sql.SQLException

Throws:

java.sql.SQLException

Method Detail

getConnection

public java.sql.Connection getConnection()
                                  throws java.sql.SQLException

XAConnection interface.

Specified by:

getConnection in interface javax.sql.PooledConnection

Overrides:

getConnection in class PGPooledConnection

Throws:

java.sql.SQLException

getXAResource

public javax.transaction.xa.XAResource getXAResource()

Specified by:

getXAResource in interface javax.sql.XAConnection

start

public void start(javax.transaction.xa.Xid xid,
                  int flags)
           throws javax.transaction.xa.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 javax.transaction.xa.XAResource

Throws:

javax.transaction.xa.XAException

end

public void end(javax.transaction.xa.Xid xid,
                int flags)
         throws javax.transaction.xa.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 javax.transaction.xa.XAResource

Throws:

javax.transaction.xa.XAException

prepare

public int prepare(javax.transaction.xa.Xid xid)
            throws javax.transaction.xa.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 javax.transaction.xa.XAResource

Throws:

javax.transaction.xa.XAException

recover

public javax.transaction.xa.Xid[] recover(int flag)
                                   throws javax.transaction.xa.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 javax.transaction.xa.XAResource

Throws:

javax.transaction.xa.XAException

rollback

public void rollback(javax.transaction.xa.Xid xid)
              throws javax.transaction.xa.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 javax.transaction.xa.XAResource

Throws:

javax.transaction.xa.XAException

commit

public void commit(javax.transaction.xa.Xid xid,
                   boolean onePhase)
            throws javax.transaction.xa.XAException

Specified by:

commit in interface javax.transaction.xa.XAResource

Throws:

javax.transaction.xa.XAException

isSameRM

public boolean isSameRM(javax.transaction.xa.XAResource xares)
                 throws javax.transaction.xa.XAException

Specified by:

isSameRM in interface javax.transaction.xa.XAResource

Throws:

javax.transaction.xa.XAException

forget

public void forget(javax.transaction.xa.Xid xid)
            throws javax.transaction.xa.XAException

Does nothing, since we don't do heuristics.

Specified by:

forget in interface javax.transaction.xa.XAResource

Throws:

javax.transaction.xa.XAException

getTransactionTimeout

public int getTransactionTimeout()

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

Specified by:

getTransactionTimeout in interface javax.transaction.xa.XAResource

setTransactionTimeout

public boolean setTransactionTimeout(int seconds)

We don't do transaction timeouts. Returns false.

Specified by:

setTransactionTimeout in interface javax.transaction.xa.XAResource