- * 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 + * put, merge, and delete operations. + * + *
+ * Performing the following put operations: + * + *
+ * 1) container { list [ a ] }
+ * 2) container { list [ b ] }
+ *
+ *
+ * will result in the following data being present:
+ *
+ *
+ * container { list [ b ] }
+ *
+ * + * Performing the following merge operations: + * + *
+ * 1) container { list [ a ] }
+ * 2) container { list [ b ] }
+ *
+ *
+ * will result in the following data being present:
+ *
+ *
+ * container { list [ a, b ] }
+ *
+ *
+ * This also means that storing the container will preserve any
+ * augmentations which have been attached to it.
+ *
+ * + * 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. *
* 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. *
* Implementation Note: This interface is not intended to be implemented * by users of MD-SAL, but only to be consumed by them. @@ -53,83 +96,22 @@ public interface AsyncWriteTransaction
, D> extends AsyncTransa * {@link TransactionStatus#NEW} or {@link TransactionStatus#SUBMITED} * * Invoking cancel() on {@link TransactionStatus#FAILED} or - * {@link TransactionStatus#CANCELED} will have no effect. - * - * @throws IllegalStateException - * If transaction status is {@link TransactionStatus#COMMITED} - * - */ - public void 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: + * {@link TransactionStatus#CANCELED} will have no effect, and transaction + * is considered cancelled. * - *
- * 1) container { list [ a ] }
- * 2) container { list [ b ] }
- *
- *
- * will result in the following data being present:
- *
- *
- * container { list [ b ] }
- *
+ * Invoking cancel() on finished transaction (future returned by {@link #submit()}
+ * already completed with {@link TransactionStatus#COMMITED}) will always
+ * fail (return false).
*
+ * @return false if the task could not be cancelled,
+ * typically because it has already completed normally;
+ * true otherwise
*
- * 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);
+ boolean cancel();
/**
- * 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:
- *
- *
- * 1) container { list [ a ] }
- * 2) container { list [ b ] }
- *
- *
- * will result in the following data being present:
- *
- *
- * container { list [ a, b ] }
- *
- *
- * This also means that storing the container will preserve any
- * augmentations which have been attached to it.
- *- * 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); - - /** - * 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 @@ -139,58 +121,80 @@ public interface AsyncWriteTransaction
, D> extends AsyncTransa * @throws IllegalStateException * if the transaction is no longer {@link TransactionStatus#NEW} */ - public void delete(LogicalDatastoreType store, P path); + void delete(LogicalDatastoreType store, P path); /** - * - * Closes transaction and resources allocated to the transaction. - * - * This call does not change Transaction status. Client SHOULD explicitly - * {@link #commit()} or {@link #cancel()} transaction. - * - * @throws IllegalStateException - * if the transaction has not been updated by invoking - * {@link #commit()} or {@link #cancel()}. - */ - @Override - public void close(); - - /** - * 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. + *
+ * Note: It is strongly recommended to process the CheckedFuture result in an asynchronous + * manner rather than using the blocking get() method. See example usage below. *
* This call logically seals the transaction, which prevents the client from * further changing data tree using this transaction. Any subsequent calls to - * {@link #put(LogicalDatastoreType, Path, Object)}, - * {@link #merge(LogicalDatastoreType, Path, Object)} or * {@link #delete(LogicalDatastoreType, Path)} will fail with * {@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. * *
* 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. - *
- * 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. + *
+ * 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. * + *
+ * 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 );
+ *
* * Transaction may fail because of multiple reasons, such as *
, D> extends AsyncTransa * which are based on same initial state, Tx 1 completes successfully * before Tx 2 is submitted. * - *
| Initial state | Tx 1 | Tx 2 | Result |
|---|---|---|---|
| Empty | put(A,1) | put(A,2) | Tx 2 will fail, state is A=1 |
| Empty | put(A,1) | merge(A,2) | A=2 |
| Initial state | Tx 1 | Tx 2 | Result |
|---|---|---|---|
| Empty | put(TOP,[]) | put(TOP,[]) | Tx 2 will fail, state is TOP=[] |