IBM DB2 Manual page 486

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470
Application Programming Guide and Reference for Java
// The XADatasource contains the user ID and password.
// Get the XAConnection object from each XADataSource
xaconn1 = xaDS1.getXAConnection();
xaconn2 = xaDS2.getXAConnection();
// Get the java.sql.Connection object from each XAConnection
conn1 = xaconn1.getConnection();
conn2 = xaconn2.getConnection();
// Get the XAResource object from each XAConnection
xares1 = xaconn1.getXAResource();
xares2 = xaconn2.getXAResource();
// Create the Xid object for this distributed transaction.
// This example uses the com.ibm.db2.jcc.DB2Xid implementation
// of the Xid interface. This Xid can be used with any JDBC driver
// that supports JTA.
javax.transaction.xa.Xid xid1 =
// Start the distributed transaction on the two connections.
// The two connections do NOT need to be started and ended together.
// They might be done in different threads, along with their SQL operations.
xares1.start(xid1, javax.transaction.xa.XAResource.TMNOFLAGS);
xares2.start(xid1, javax.transaction.xa.XAResource.TMNOFLAGS);
// Do the SQL operations on connection 1.
// Do the SQL operations on connection 2.
// Now end the distributed transaction on the two connections.
xares1.end(xid1, javax.transaction.xa.XAResource.TMSUCCESS);
xares2.end(xid1, javax.transaction.xa.XAResource.TMSUCCESS);
// If connection 2 work had been done in another thread,
// a thread.join() call would be needed here to wait until the
// connection 2 work is done.
try
{ // Now prepare both branches of the distributed transaction.
// Both branches must prepare successfully before changes
// can be committed.
// If the distributed transaction fails, an XAException is thrown.
rc1 = xares1.prepare(xid1);
if(rc1 == javax.transaction.xa.XAResource.XA_OK)
{ // Prepare was successful. Prepare the second connection.
rc2 = xares2.prepare(xid1);
if(rc2 == javax.transaction.xa.XAResource.XA_OK)
{ // Both connections prepared successfully and neither was read-only.
xares1.commit(xid1, false);
xares2.commit(xid1, false);
}
else if(rc2 == javax.transaction.xa.XAException.XA_RDONLY)
{ // The second connection is read-only, so just commit the
// first connection.
xares1.commit(xid1, false);
}
}
else if(rc1 == javax.transaction.xa.XAException.XA_RDONLY)
{ // SQL for the first connection is read-only (such as a SELECT).
// The prepare committed it. Prepare the second connection.
rc2 = xares2.prepare(xid1);
if(rc2 == javax.transaction.xa.XAResource.XA_OK)
{ // The first connection is read-only but the second is not.
// Commit the second connection.
xares2.commit(xid1, false);
}
else if(rc2 == javax.transaction.xa.XAException.XA_RDONLY)
{ // Both connections are read-only, and both already committed,
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new com.ibm.db2.jcc.DB2Xid(100, gtrid, bqual);