import org.opendaylight.yangtools.concepts.Path;
import org.opendaylight.yangtools.yang.common.RpcResult;
+import com.google.common.util.concurrent.CheckedFuture;
import com.google.common.util.concurrent.ListenableFuture;
/**
* change for the data tree and it is not visible to any other concurrently running
* transaction.
* <p>
- * Applications publish the changes proposed in the transaction by calling {@link #commit}
- * on the transaction. This seals the transaction
+ * Applications make changes to the local data tree in the transaction by via the
+ * <b>put</b>, <b>merge</b>, and <b>delete</b> operations.
+ *
+ * <h2>Put operation</h2>
+ * Stores a piece of data at a specified path. This acts as an add / replace
+ * operation, which is to say that whole subtree will be replaced by the
+ * specified data.
+ * <p>
+ * Performing the following put operations:
+ *
+ * <pre>
+ * 1) container { list [ a ] }
+ * 2) container { list [ b ] }
+ * </pre>
+ *
+ * will result in the following data being present:
+ *
+ * <pre>
+ * container { list [ b ] }
+ * </pre>
+ * <h2>Merge operation</h2>
+ * Merges a piece of data with the existing data at a specified path. Any pre-existing data
+ * which is not explicitly overwritten will be preserved. This means that if you store a container,
+ * its child lists will be merged.
+ * <p>
+ * Performing the following merge operations:
+ *
+ * <pre>
+ * 1) container { list [ a ] }
+ * 2) container { list [ b ] }
+ * </pre>
+ *
+ * will result in the following data being present:
+ *
+ * <pre>
+ * container { list [ a, b ] }
+ * </pre>
+ *
+ * This also means that storing the container will preserve any
+ * augmentations which have been attached to it.
+ *
+ * <h2>Delete operation</h2>
+ * Removes a piece of data from a specified path.
+ * <p>
+ * After applying changes to the local data tree, applications publish the changes proposed in the
+ * transaction by calling {@link #submit} on the transaction. This seals the transaction
* (preventing any further writes using this transaction) and submits it to be
* processed and applied to global conceptual data tree.
* <p>
* The transaction commit may fail due to a concurrent transaction modifying and committing data in
- * an incompatible way. See {@link #commit()} for more concrete commit failure examples.
- *
- *
+ * an incompatible way. See {@link #submit} for more concrete commit failure examples.
* <p>
* <b>Implementation Note:</b> This interface is not intended to be implemented
* by users of MD-SAL, but only to be consumed by them.
* {@link TransactionStatus#CANCELED} will have no effect, and transaction
* is considered cancelled.
*
- * Invoking cancel() on finished transaction (future returned by {@link #commit()}
+ * Invoking cancel() on finished transaction (future returned by {@link #submit()}
* already completed with {@link TransactionStatus#COMMITED}) will always
* fail (return false).
*
* <tt>true</tt> otherwise
*
*/
- public boolean cancel();
-
- /**
- * Store a piece of data at specified path. This acts as an add / replace
- * operation, which is to say that whole subtree will be replaced by
- * specified path. Performing the following put operations:
- *
- * <pre>
- * 1) container { list [ a ] }
- * 2) container { list [ b ] }
- * </pre>
- *
- * will result in the following data being present:
- *
- * <pre>
- * container { list [ b ] }
- * </pre>
- *
- *
- * If you need to make sure that a parent object exists, but you do not want modify
- * its preexisting state by using put, consider using
- * {@link #merge(LogicalDatastoreType, Path, Object)}
- *
- * @param store
- * Logical data store which should be modified
- * @param path
- * Data object path
- * @param data
- * Data object to be written to specified path
- * @throws IllegalStateException
- * if the transaction is no longer {@link TransactionStatus#NEW}
- */
- public void put(LogicalDatastoreType store, P path, D data);
-
- /**
- * Store a piece of data at the specified path. This acts as a merge operation,
- * which is to say that any pre-existing data which is not explicitly
- * overwritten will be preserved. This means that if you store a container,
- * its child lists will be merged. Performing the following merge
- * operations:
- *
- * <pre>
- * 1) container { list [ a ] }
- * 2) container { list [ b ] }
- * </pre>
- *
- * will result in the following data being present:
- *
- * <pre>
- * container { list [ a, b ] }
- * </pre>
- *
- * This also means that storing the container will preserve any
- * augmentations which have been attached to it.
- *<p>
- * If you require an explicit replace operation, use
- * {@link #put(LogicalDatastoreType, Path, Object)} instead.
- *
- * @param store
- * Logical data store which should be modified
- * @param path
- * Data object path
- * @param data
- * Data object to be written to specified path
- * @throws IllegalStateException
- * if the transaction is no longer {@link TransactionStatus#NEW}
- */
- public void merge(LogicalDatastoreType store, P path, D data);
+ boolean cancel();
/**
- * Remove a piece of data from specified path. This operation does not fail
+ * Removes a piece of data from specified path. This operation does not fail
* if the specified path does not exist.
*
* @param store
* @throws IllegalStateException
* if the transaction is no longer {@link TransactionStatus#NEW}
*/
- public void delete(LogicalDatastoreType store, P path);
+ void delete(LogicalDatastoreType store, P path);
/**
- * Submits transaction to be applied to update logical data tree.
+ * Submits this transaction to be asynchronously applied to update the logical data tree.
+ * The returned CheckedFuture conveys the result of applying the data changes.
+ * <p>
+ * <b>Note:</b> It is strongly recommended to process the CheckedFuture result in an asynchronous
+ * manner rather than using the blocking get() method. See example usage below.
* <p>
* This call logically seals the transaction, which prevents the client from
* further changing data tree using this transaction. Any subsequent calls to
* {@link IllegalStateException}.
*
* The transaction is marked as {@link TransactionStatus#SUBMITED} and
- * enqueued into the data store backed for processing.
+ * enqueued into the data store back-end for processing.
*
* <p>
* Whether or not the commit is successful is determined by versioning
- * of data tree and validation of registered commit participants
- * {@link AsyncConfigurationCommitHandler}
- * if transaction changes {@link LogicalDatastoreType#CONFIGURATION} data tree.
- *<p>
- * The effects of successful commit of data depends on
- * other data change listeners {@link AsyncDataChangeListener} and
- * {@link AsyncConfigurationCommitHandler}, which was registered to the
- * same {@link AsyncDataBroker}, to which this transaction belongs.
- *
+ * of the data tree and validation of registered commit participants
+ * ({@link AsyncConfigurationCommitHandler})
+ * if the transaction changes the data tree.
+ * <p>
+ * The effects of a successful commit of data depends on data change listeners
+ * ({@link AsyncDataChangeListener}) and commit participants
+ * ({@link AsyncConfigurationCommitHandler}) that are registered with the data broker.
+ * <p>
+ * <h3>Example usage:</h3>
+ * <pre>
+ * private void doWrite( final int tries ) {
+ * WriteTransaction writeTx = dataBroker.newWriteOnlyTransaction();
+ *
+ * MyDataObject data = ...;
+ * InstanceIdentifier<MyDataObject> path = ...;
+ * writeTx.put( LogicalDatastoreType.OPERATIONAL, path, data );
+ *
+ * Futures.addCallback( writeTx.submit(), new FutureCallback<Void>() {
+ * public void onSuccess( Void result ) {
+ * // succeeded
+ * }
+ *
+ * public void onFailure( Throwable t ) {
+ * if( t instanceof OptimisticLockFailedException ) {
+ * if( ( tries - 1 ) > 0 ) {
+ * // do retry
+ * doWrite( tries - 1 );
+ * } else {
+ * // out of retries
+ * }
+ * } else {
+ * // failed due to another type of TransactionCommitFailedException.
+ * }
+ * } );
+ * }
+ * ...
+ * doWrite( 2 );
+ * </pre>
* <h2>Failure scenarios</h2>
* <p>
* Transaction may fail because of multiple reasons, such as
* <ul>
- * <li>Another transaction finished earlier and modified the same node in
- * non-compatible way (see below). In this case the returned future will fail with
+ * <li>Another transaction finished earlier and modified the same node in a
+ * non-compatible way (see below). In this case the returned future will fail with an
* {@link OptimisticLockFailedException}. It is the responsibility of the
* caller to create a new transaction and submit the same modification again in
- * order to update data tree.</li>
+ * order to update data tree. <i><b>Warning</b>: In most cases, retrying after an
+ * OptimisticLockFailedException will result in a high probability of success.
+ * However, there are scenarios, albeit unusual, where any number of retries will
+ * not succeed. Therefore it is strongly recommended to limit the number of retries (2 or 3)
+ * to avoid an endless loop.</i>
+ * </li>
* <li>Data change introduced by this transaction did not pass validation by
* commit handlers or data was incorrectly structured. Returned future will
- * fail with {@link DataValidationFailedException}. User should not retry to
+ * fail with a {@link DataValidationFailedException}. User should not retry to
* create new transaction with same data, since it probably will fail again.
* </li>
* </ul>
* txA.put(CONFIGURATION, PATH, A); // writes to PATH value A
* txB.put(CONFIGURATION, PATH, B) // writes to PATH value B
*
- * ListenableFuture futureA = txA.commit(); // transaction A is sealed and committed
- * ListenebleFuture futureB = txB.commit(); // transaction B is sealed and committed
+ * ListenableFuture futureA = txA.submit(); // transaction A is sealed and submitted
+ * ListenebleFuture futureB = txB.submit(); // transaction B is sealed and submitted
* </pre>
*
* Commit of transaction A will be processed asynchronously and data tree
* with {@link OptimisticLockFailedException} exception, which indicates to
* client that concurrent transaction prevented the submitted transaction from being
* applied.
- *
- * @return Result of the Commit, containing success information or list of
- * encountered errors, if commit was not successful. The Future
- * blocks until {@link TransactionStatus#COMMITED} is reached.
- * Future will fail with {@link TransactionCommitFailedException} if
- * Commit of this transaction failed. TODO: Usability: Consider
- * change from ListenableFuture to
- * {@link com.google.common.util.concurrent.CheckedFuture} which
- * will throw {@link TransactionCommitFailedException}.
+ * <br>
+ * @return a CheckFuture containing the result of the commit. The Future blocks until the
+ * commit operation is complete. A successful commit returns nothing. On failure,
+ * the Future will fail with a {@link TransactionCommitFailedException} or an exception
+ * derived from TransactionCommitFailedException.
*
* @throws IllegalStateException
* if the transaction is not {@link TransactionStatus#NEW}
*/
- public ListenableFuture<RpcResult<TransactionStatus>> commit();
+ CheckedFuture<Void,TransactionCommitFailedException> submit();
+
+ /**
+ * @deprecated Use {@link #submit()} instead.
+ */
+ @Deprecated
+ ListenableFuture<RpcResult<TransactionStatus>> commit();
}
Code Review / controller.git / blobdiff