X-Git-Url: https://git.opendaylight.org/gerrit/gitweb?a=blobdiff_plain;f=opendaylight%2Fmd-sal%2Fsal-common-api%2Fsrc%2Fmain%2Fjava%2Forg%2Fopendaylight%2Fcontroller%2Fmd%2Fsal%2Fcommon%2Fapi%2Fdata%2FAsyncWriteTransaction.java;h=e47b54a0a1e6e138292530994a57b539501fc1bb;hb=49346407810110d0cf9ed7fc9470e0fbb4562499;hp=82c48d2ddb27e657c12cb9c8f56f49997923b370;hpb=b1ad47e987f7e73ebcd44f2076f57550715f75d6;p=controller.git diff --git a/opendaylight/md-sal/sal-common-api/src/main/java/org/opendaylight/controller/md/sal/common/api/data/AsyncWriteTransaction.java b/opendaylight/md-sal/sal-common-api/src/main/java/org/opendaylight/controller/md/sal/common/api/data/AsyncWriteTransaction.java index 82c48d2ddb..e47b54a0a1 100644 --- a/opendaylight/md-sal/sal-common-api/src/main/java/org/opendaylight/controller/md/sal/common/api/data/AsyncWriteTransaction.java +++ b/opendaylight/md-sal/sal-common-api/src/main/java/org/opendaylight/controller/md/sal/common/api/data/AsyncWriteTransaction.java @@ -11,111 +11,312 @@ import org.opendaylight.controller.md.sal.common.api.TransactionStatus; 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; -public interface AsyncWriteTransaction
, D> extends AsyncTransaction
{ +/** + * Write transaction provides mutation capabilities for a data tree. + * + *
+ * Initial state of write transaction is a stable snapshot of the current data tree. + * The state is captured when the transaction is created and its state and underlying + * data tree are not affected by other concurrently running transactions. + *
+ * 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 ] } + *+ * + * 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 #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. + * + * @param
+ * Type of path (subtree identifier), which represents location in
+ * tree
+ * @param , D> extends AsyncTransaction {
/**
- * Cancels transaction.
+ * Cancels the transaction.
+ *
+ * Transactions can only be cancelled if it's status is
+ * {@link TransactionStatus#NEW} or {@link TransactionStatus#SUBMITED}
*
- * Transaction could be only cancelled if it's status
- * is {@link TransactionStatus#NEW} or {@link TransactionStatus#SUBMITED}
+ * Invoking cancel() on {@link TransactionStatus#FAILED} or
+ * {@link TransactionStatus#CANCELED} will have no effect, and transaction
+ * is considered cancelled.
*
- * Invoking cancel() on {@link TransactionStatus#FAILED} or {@link TransactionStatus#CANCELED}
- * will have no effect.
+ * Invoking cancel() on finished transaction (future returned by {@link #submit()}
+ * already completed with {@link TransactionStatus#COMMITED}) will always
+ * fail (return false).
*
- * @throws IllegalStateException If transaction status is {@link TransactionStatus#COMMITED}
+ * @return false if the task could not be cancelled,
+ * typically because it has already completed normally;
+ * true otherwise
*
*/
- public void cancel();
+ boolean cancel();
/**
- * Store a piece of data at specified path. This acts as a add / replace operation,
- * which is to say that whole subtree will be replaced by specified path.
- *
- * If you need add or merge of current object with specified use {@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}
+ * @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 put(LogicalDatastoreType store, P path, D data);
+ void delete(LogicalDatastoreType store, P path);
/**
- * Store a piece of data at 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 put 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.
+ *
+ * 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}.
*
- * 1) container { list [ a ] }
- * 2) container { list [ b ] }
+ * The transaction is marked as {@link TransactionStatus#SUBMITED} and
+ * enqueued into the data store back-end for processing.
*
- * will result in the following data being present:
+ *
+ * Whether or not the commit is successful is determined by versioning
+ * 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.
+ *
+ *
+ * Transaction may fail because of multiple reasons, such as
+ *
- * The successful commit changes the state of the system and may affect
- * several components.
- *
- *
- * The effects of successful commit of data are described in the
- * specifications and YANG models describing the Provider components of
- * controller. It is assumed that Consumer has an understanding of this
- * changes.
- *
- * @see DataCommitHandler for further information how two-phase commit is
- * processed.
- * @param store Identifier of the store, where commit should occur.
- * @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.
- *
- * @throws IllegalStateException if the transaction is not {@link TransactionStatus#NEW}
+ * @deprecated Use {@link #submit()} instead.
*/
- public ListenableFutureExample usage:
+ *
+ * private void doWrite( final int tries ) {
+ * WriteTransaction writeTx = dataBroker.newWriteOnlyTransaction();
*
- * container { list [ a, b ] }
+ * MyDataObject data = ...;
+ * InstanceIdentifier
+ * Failure scenarios
+ *
+ *
*
- * @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.
+ * Change compatibility
*
- * @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);
-
- /**
+ * 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.
*
- * Closes transaction and resources allocated to the transaction.
+ * Change compatibility of leafs, leaf-list items
*
- * This call does not change Transaction status. Client SHOULD
- * explicitly {@link #commit()} or {@link #cancel()} transaction.
+ * 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.
*
- * @throws IllegalStateException if the transaction has not been
- * updated by invoking {@link #commit()} or {@link #cancel()}.
+ *
+ *
+ *
+ *
+ * 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 submitted.
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ * 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.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 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}
*/
- @Override
- public void close();
+ CheckedFuture