This class provides an implementation of the start transaction extended
request as defined in
RFC 5805. It may be used
to begin a transaction that allows multiple write operations to be processed
as a single atomic unit. The
StartTransactionExtendedResult that is
returned will include a transaction ID. For each operation that is performed
as part of the transaction, this transaction ID should be included in the
corresponding request through the
TransactionSpecificationRequestControl. Finally, after all requests
for the transaction have been submitted to the server, the
EndTransactionExtendedRequest should be used to commit that
transaction, or it may also be used to abort the transaction if it is decided
that it is no longer needed.
Example
The following example demonstrates the process for using LDAP transactions.
It will modify two different entries as a single atomic unit.
// Use the start transaction extended operation to begin a transaction.
StartTransactionExtendedResult startTxnResult;
try
{
startTxnResult = (StartTransactionExtendedResult)
connection.processExtendedOperation(
new StartTransactionExtendedRequest());
// This doesn't necessarily mean that the operation was successful, since
// some kinds of extended operations return non-success results under
// normal conditions.
}
catch (LDAPException le)
{
// For an extended operation, this generally means that a problem was
// encountered while trying to send the request or read the result.
startTxnResult = new StartTransactionExtendedResult(
new ExtendedResult(le));
}
LDAPTestUtils.assertResultCodeEquals(startTxnResult, ResultCode.SUCCESS);
ASN1OctetString txnID = startTxnResult.getTransactionID();
// At this point, we have a transaction available for use. If any problem
// arises, we want to ensure that the transaction is aborted, so create a
// try block to process the operations and a finally block to commit or
// abort the transaction.
boolean commit = false;
try
{
// Create and process a modify operation to update a first entry as part
// of the transaction. Make sure to include the transaction specification
// control in the request to indicate that it should be part of the
// transaction.
ModifyRequest firstModifyRequest = new ModifyRequest(
"cn=first,dc=example,dc=com",
new Modification(ModificationType.REPLACE, "description", "first"));
firstModifyRequest.addControl(
new TransactionSpecificationRequestControl(txnID));
LDAPResult firstModifyResult;
try
{
firstModifyResult = connection.modify(firstModifyRequest);
}
catch (LDAPException le)
{
firstModifyResult = le.toLDAPResult();
}
LDAPTestUtils.assertResultCodeEquals(firstModifyResult,
ResultCode.SUCCESS);
// Perform a second modify operation as part of the transaction.
ModifyRequest secondModifyRequest = new ModifyRequest(
"cn=second,dc=example,dc=com",
new Modification(ModificationType.REPLACE, "description", "second"));
secondModifyRequest.addControl(
new TransactionSpecificationRequestControl(txnID));
LDAPResult secondModifyResult;
try
{
secondModifyResult = connection.modify(secondModifyRequest);
}
catch (LDAPException le)
{
secondModifyResult = le.toLDAPResult();
}
LDAPTestUtils.assertResultCodeEquals(secondModifyResult,
ResultCode.SUCCESS);
// If we've gotten here, then all writes have been processed successfully
// and we can indicate that the transaction should be committed rather
// than aborted.
commit = true;
}
finally
{
// Commit or abort the transaction.
EndTransactionExtendedResult endTxnResult;
try
{
endTxnResult = (EndTransactionExtendedResult)
connection.processExtendedOperation(
new EndTransactionExtendedRequest(txnID, commit));
}
catch (LDAPException le)
{
endTxnResult = new EndTransactionExtendedResult(new ExtendedResult(le));
}
LDAPTestUtils.assertResultCodeEquals(endTxnResult, ResultCode.SUCCESS);
}