Package com.unboundid.ldap.sdk.unboundidds.extensions

Class StartBatchedTransactionExtendedRequest

java.lang.Object
com.unboundid.ldap.sdk.LDAPRequest
com.unboundid.ldap.sdk.ExtendedRequest
com.unboundid.ldap.sdk.unboundidds.extensions.StartBatchedTransactionExtendedRequest
All Implemented Interfaces:
ProtocolOp, ReadOnlyLDAPRequest, Serializable
@NotMutable @ThreadSafety(level=NOT_THREADSAFE) public final class StartBatchedTransactionExtendedRequest extends ExtendedRequest
This class provides an implementation of the start batched transaction extended request. It may be used to begin a transaction that allows multiple write operations to be processed as a single atomic unit. The StartBatchedTransactionExtendedResult that is returned will include a 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 BatchedTransactionSpecificationRequestControl. Finally, after all requests for the transaction have been submitted to the server, the EndBatchedTransactionExtendedRequest 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.
NOTE: This class, and other classes within the com.unboundid.ldap.sdk.unboundidds package structure, are only supported for use against Ping Identity, UnboundID, and Nokia/Alcatel-Lucent 8661 server products. These classes provide support for proprietary functionality or for external specifications that are not considered stable or mature enough to be guaranteed to work in an interoperable way with other types of LDAP servers.

Transactions processed using this mechanism are called "batched transactions" because the associated requests are collected in the server and are only processed once the EndBatchedTransactionExtendedRequest has been received to indicate that the transaction should be committed. As a result, it is only possible to include write operations (in particular, add, delete, modify, modify DN, and password modify operations) in a batched transaction. Read operations (like search, bind, and compare) cannot be included in a batched transaction. However, it is possible to use some controls within the transaction and they may prove to be sufficient in many cases. The controls that can be included in operations that are part of a batched transaction include: In particular, the assertion control may be used to ensure that an operation is only performed if the target entry matches a given filter (which allows for an atomic compare-and-swap operation), and the pre-read and post-read controls may be used to retrieve a copy of an entry immediately before or immediately after the operation was performed.

Note that even though the operations which are part of this transaction aren't actually processed until the end batched transaction request is received, the directory server will send back a response for each operation that is to be performed as part of the transaction. If the result of this response is ResultCode.SUCCESS, then it means that the server has accepted the operation and it will be processed when the end batched transaction request is received indicating that the transaction should be committed. However, if it has some other result then it indicates that the request may have been malformed or did not meet the requirements for the transaction (e.g., it included a control that is not allowed for a transaction). Note that even if the server returns a non-success response for an operation prior to the end batched transaction request, the transaction will still be active in the server and other operations may still be included in the transaction if desired. If it is no longer desirable to process the transaction, then the end batched transaction request should be used to abort the transaction.

Example

The following example demonstrates the process for using batched transactions. It will modify two different entries as a single atomic unit. 
 // Use the start transaction extended operation to begin a transaction.
 StartBatchedTransactionExtendedResult startTxnResult;
 try
 {
   startTxnResult = (StartBatchedTransactionExtendedResult)
        connection.processExtendedOperation(
             new StartBatchedTransactionExtendedRequest());
   // 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 StartBatchedTransactionExtendedResult(
        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 BatchedTransactionSpecificationRequestControl(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 BatchedTransactionSpecificationRequestControl(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.
   EndBatchedTransactionExtendedResult endTxnResult;
   try
   {
     endTxnResult = (EndBatchedTransactionExtendedResult)
          connection.processExtendedOperation(
               new EndBatchedTransactionExtendedRequest(txnID, commit));
   }
   catch (LDAPException le)
   {
     endTxnResult = new EndBatchedTransactionExtendedResult(
          new ExtendedResult(le));
   }
   LDAPTestUtils.assertResultCodeEquals(endTxnResult, ResultCode.SUCCESS);
 }
See Also: