- * This method does not automatically create missing parent nodes. It is equivalent to invoking
- * {@link #put(LogicalDatastoreType, InstanceIdentifier, DataObject, boolean)}
- * with createMissingParents set to false.
+ * Cancels the transaction. Transactions can only be cancelled if it was not yet committed.
+ * Invoking cancel() on failed or already canceled will have no effect, and transaction is considered cancelled.
+ * Invoking cancel() on finished transaction (future returned by {@link #commit()} already successfully completed)
+ * will always fail (return false).
*
- *
- * For more information on usage and examples, please see the documentation in {@link AsyncWriteTransaction}. - *
- * If you need to make sure that a parent object exists but you do not want modify
- * its pre-existing state by using put, consider using {@link #merge} instead.
- *
- * @param store the logical data store which should be modified
- * @param path the data object path
- * @param data the data object to be written to the specified path
- * @throws IllegalStateException if the transaction has already been submitted
- * @throws NullPointerException if any of the arguments is null
+ * @return {@code false} if the task could not be cancelled, typically because it has already completed normally;
+ * {@code true} otherwise
*/
-
- * For more information on usage and examples, please see the documentation
- * in {@link AsyncWriteTransaction}.
+ * This call logically seals the transaction, which prevents the client from further changing the data tree using
+ * this transaction. Any subsequent calls to
- * If you need to make sure that a parent object exists but you do not want
- * modify its pre-existing state by using put, consider using {@link #merge}
- * instead.
+ * Whether or not the commit is successful is determined by versioning of the data tree and validation of registered
+ * commit participants if the transaction changes the data tree.
*
*
- * Note: Using
- * This method does not automatically create missing parent nodes. It is equivalent to invoking
- * {@link #merge(LogicalDatastoreType, InstanceIdentifier, DataObject, boolean)}
- * with
- * For more information on usage and examples, please see the documentation in {@link AsyncWriteTransaction}.
+ *
- * If you require an explicit replace operation, use {@link #put} instead.
- * @param store the logical data store which should be modified
- * @param path the data object path
- * @param data the data object to be merged to the specified path
- * @throws IllegalStateException if the transaction has already been submitted
- * @throws NullPointerException if any of the arguments is null
- */
-
- * For more information on usage and examples, please see the documentation in {@link AsyncWriteTransaction}.
+ *
- * If you require an explicit replace operation, use {@link #put} instead.
- *
- * @param store the logical data store which should be modified
- * @param path the data object path
- * @param data the data object to be merged to the specified path
- * @param createMissingParents if {@link #CREATE_MISSING_PARENTS}, any missing parent nodes will be automatically
- * created using a merge operation.
- * @throws IllegalStateException if the transaction has already been submitted
- * @throws NullPointerException if any of the arguments is null
- */
- put(LogicalDatastoreType, Path, Object),
+ * merge(LogicalDatastoreType, Path, Object), delete(LogicalDatastoreType, Path) will fail
+ * with {@link IllegalStateException}. The transaction is marked as committed and enqueued into the data store
+ * back-end for processing.
*
* createMissingParents with value true, may
- * introduce garbage in data store, or recreate nodes, which were deleted by
- * previous transaction.
- *
- * @param store the logical data store which should be modified
- * @param path the data object path
- * @param data the data object to be written to the specified path
- * @param createMissingParents if {@link #CREATE_MISSING_PARENTS}, any missing parent nodes will be automatically
- * created using a merge operation.
- * @throws IllegalStateException if the transaction has already been submitted
- * @throws NullPointerException if any of the arguments is null
- */
- createMissingParents set to false.
+ * Example usage:
+ *
+ * private void doWrite(final int tries) {
+ * WriteTransaction writeTx = dataBroker.newWriteOnlyTransaction();
+ * MyDataObject data = ...;
+ * InstanceIdentifier<MyDataObject> path = ...;
+ * writeTx.put(LogicalDatastoreType.OPERATIONAL, path, data);
+ * Futures.addCallback(writeTx.commit(), new FutureCallback<CommitInfo>() {
+ * public void onSuccess(CommitInfo 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);
+ *
*
- * Failure scenarios
*
*
+ *
*
- * Change compatibility
+ * 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 level.
+ *
+ * Change compatibility of leafs, leaf-list items
+ * 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 committed.
+ *
+ *
+ *
+ *
+ *
+ *
+ * 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
+ *
+ *
+ * Empty
+ * merge(A,1)
+ * put(A,2)
+ * Tx 2 will fail, state is A=1
+ *
+ *
+ *
+ *
+ * Empty
+ * merge(A,1)
+ * merge(A,2)
+ * A=2
+ *
+ *
+ * A=0
+ * put(A,1)
+ * put(A,2)
+ * Tx 2 will fail, A=1
+ *
+ *
+ * A=0
+ * put(A,1)
+ * merge(A,2)
+ * A=2
+ *
+ *
+ * A=0
+ * merge(A,1)
+ * put(A,2)
+ * Tx 2 will fail, A=1
+ *
+ *
+ *
+ * A=0
+ * merge(A,1)
+ * merge(A,2)
+ * A=2
+ *
+ *
+ * A=0
+ * delete(A)
+ * put(A,2)
+ * Tx 2 will fail, A does not exists
+ *
+ *
+ * A=0
+ * delete(A)
+ * merge(A,2)
+ * A=2
+ * Change compatibility of subtrees
+ * 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 committed.
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ * 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])
+ * 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])
+ * 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])
+ * 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])
+ * 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])
+ * state is TOP=[BAR=1]
+ *
+ *
+ * TOP=[]
+ * put(TOP/FOO,1)
+ * put(TOP/BAR,1])
+ * state is TOP=[FOO=1,BAR=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)
+ * 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=[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]
+ * 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]
+ * Examples of failure scenarios
+ *
+ * Conflict of two transactions
+ * This example illustrates two concurrent transactions, which derived from same initial state
+ * of data tree and proposes conflicting modifications.
+ *
+ *
+ * txA = broker.newWriteTransaction(); // allocates new transaction, data tree is empty
+ * txB = broker.newWriteTransaction(); // allocates new transaction, data tree is empty
+ * 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
+ *
+ * Commit of transaction A will be processed asynchronously and data tree will be updated to
+ * contain value A for PATH. Returned {@link FluentFuture} 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 FluentFuture} object will fail with {@link OptimisticLockFailedException}
+ * exception, which indicates to client that concurrent transaction prevented the committed
+ * transaction from being applied.
*
*