* Write transactions are isolated from other concurrent write transactions. All * writes are local to the transaction and represent only a proposal of state * change for the data tree and it is not visible to any other concurrently running * 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 ] }
+ *
+ *
* - * Applications publish the changes proposed in the transaction by calling {@link #commit} - * on the transaction. This seals the transaction + * 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 @@ -49,146 +99,118 @@ public interface AsyncWriteTransaction
, D> extends AsyncTransa /** * Cancels the transaction. * - * Transactions can only be cancelled if it's status is - * {@link TransactionStatus#NEW} or {@link TransactionStatus#SUBMITED} + *
+ * Transactions can only be cancelled if it's state is new or submitted. * - * Invoking cancel() on {@link TransactionStatus#FAILED} or - * {@link TransactionStatus#CANCELED} will have no effect, and transaction + *
+ * Invoking cancel() on a failed or cancelled transaction will have no effect, and transaction * is considered cancelled. * - * Invoking cancel() on finished transaction (future returned by {@link #commit()} - * already completed with {@link TransactionStatus#COMMITED}) will always + *
+ * Invoking cancel() on a finished transaction (future returned by {@link #submit()} already completed will always * fail (return false). * - * @return false if the task could not be cancelled, - * typically because it has already completed normally; + * @return false if the task could not be cancelled, typically because it has already completed normally * true otherwise * */ - public boolean cancel(); + 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: - * - *
- * 1) container { list [ a ] }
- * 2) container { list [ b ] }
- *
- *
- * will result in the following data being present:
- *
- *
- * container { list [ b ] }
- *
- *
- *
- * 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)}
+ * Removes a piece of data from specified path. This operation does not fail
+ * if the specified path does not exist.
*
* @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}
+ * if the transaction as already been submitted or cancelled
*/
- public void put(LogicalDatastoreType store, P path, D data);
+ void delete(LogicalDatastoreType store, P path);
/**
- * 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:
+ * Submits this transaction to be asynchronously applied to update the logical data tree.
+ * The returned CheckedFuture conveys the result of applying the data changes.
*
- *
- * 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 - * if the specified path does not exist. + *
+ * 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. * - * @param store - * Logical data store which should be modified - * @param path - * Data object path - * @throws IllegalStateException - * if the transaction is no longer {@link TransactionStatus#NEW} - */ - public void delete(LogicalDatastoreType store, P path); - - /** - * Submits transaction to be applied to update logical data tree. *
* 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. + *
+ * The transaction is marked as submitted and 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 *
* There are several sets of changes which could be considered incompatible * between two transactions which are derived from same initial state. * Rules for conflict detection applies recursively for each subtree @@ -196,11 +218,12 @@ public interface AsyncWriteTransaction
, D> extends AsyncTransa * *
* Following table shows state changes and failures between two concurrent transactions, * 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=[] |
| Empty | put(TOP,[]) | merge(TOP,[]) | TOP=[] |
| Empty | put(TOP,[FOO=1]) | put(TOP,[BAR=1]) | Tx 2 will fail, state is TOP=[FOO=1] |
| Empty | put(TOP,[FOO=1]) | put(TOP,[BAR=1]) | Tx 2 will fail, state is TOP=[FOO=1] + * |
| Empty | put(TOP,[FOO=1]) | merge(TOP,[BAR=1]) | TOP=[FOO=1,BAR=1] |
| Empty | merge(TOP,[FOO=1]) | put(TOP,[BAR=1]) | Tx 2 will fail, state is TOP=[FOO=1] |
| Empty | merge(TOP,[FOO=1]) | put(TOP,[BAR=1]) | Tx 2 will fail, state is TOP=[FOO=1] + * |
| Empty | merge(TOP,[FOO=1]) | merge(TOP,[BAR=1]) | TOP=[FOO=1,BAR=1] |
| TOP=[] | put(TOP,[FOO=1]) | put(TOP,[BAR=1]) | Tx 2 will fail, state is TOP=[FOO=1] |
| TOP=[] | put(TOP,[FOO=1]) | put(TOP,[BAR=1]) | Tx 2 will fail, state is TOP=[FOO=1] + * |
| TOP=[] | put(TOP,[FOO=1]) | merge(TOP,[BAR=1]) | state is TOP=[FOO=1,BAR=1] |
| TOP=[] | merge(TOP,[FOO=1]) | put(TOP,[BAR=1]) | Tx 2 will fail, state is TOP=[FOO=1] |
| TOP=[] | merge(TOP,[FOO=1]) | put(TOP,[BAR=1]) | Tx 2 will fail, state is TOP=[FOO=1] + * |
| TOP=[] | merge(TOP,[FOO=1]) | merge(TOP,[BAR=1]) | state is TOP=[FOO=1,BAR=1] |
| TOP=[] | delete(TOP) | put(TOP,[BAR=1]) | Tx 2 will fail, state is empty store |
| TOP=[] | delete(TOP) | put(TOP,[BAR=1]) | Tx 2 will fail, state is empty store + * |
| TOP=[] | delete(TOP) | merge(TOP,[BAR=1]) | state is TOP=[BAR=1] |
| TOP=[] | put(TOP/FOO,1) | put(TOP/BAR,1]) | state is TOP=[FOO=1,BAR=1] |
| TOP=[] | merge(TOP/FOO,1) | put(TOP/BAR,1) | state is TOP=[FOO=1,BAR=1] |
| TOP=[] | merge(TOP/FOO,1) | merge(TOP/BAR,1) | state is TOP=[FOO=1,BAR=1] |
| TOP=[] | delete(TOP) | put(TOP/BAR,1) | Tx 2 will fail, state is empty store |
| TOP=[] | delete(TOP) | merge(TOP/BAR,1] | Tx 2 will fail, state is empty store |
| TOP=[] | delete(TOP) | merge(TOP/BAR,1] | Tx 2 will fail, state is empty store + * |
| TOP=[FOO=1] | put(TOP/FOO,2) | put(TOP/BAR,1) | state is TOP=[FOO=2,BAR=1] |
| TOP=[FOO=1] | put(TOP/FOO,2) | merge(TOP/BAR,1) | state is TOP=[FOO=2,BAR=1] |
| TOP=[FOO=1] | merge(TOP/FOO,2) | put(TOP/BAR,1) | state is TOP=[FOO=2,BAR=1] |
| TOP=[FOO=1] | merge(TOP/FOO,2) | merge(TOP/BAR,1) | state is TOP=[FOO=2,BAR=1] |
| TOP=[FOO=1] | merge(TOP/FOO,2) | merge(TOP/BAR,1) | state is TOP=[FOO=2,BAR=1] + * |
| TOP=[FOO=1] | delete(TOP/FOO) | put(TOP/BAR,1) | state is TOP=[BAR=1] |
| TOP=[FOO=1] | delete(TOP/FOO) | merge(TOP/BAR,1] | state is TOP=[BAR=1] |
, D> extends AsyncTransa * *
* This example illustrates two concurrent transactions, which derived from * same initial state of data tree and proposes conflicting modifications. * @@ -273,34 +305,31 @@ public interface AsyncWriteTransaction
, D> extends AsyncTransa * 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 * * + *
* Commit of transaction A will be processed asynchronously and data tree
* will be updated to contain value A for PATH.
* Returned {@link ListenableFuture} will successfully complete once
* state is applied to data tree.
*
+ *
* Commit of Transaction B will fail, because previous transaction also
* modified path in a concurrent way. The state introduced by transaction B
* will not be applied. Returned {@link ListenableFuture} object will fail
* 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}.
+ *
+ * @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}
+ * if the transaction is not new
*/
- public ListenableFuture