X-Git-Url: https://git.opendaylight.org/gerrit/gitweb?a=blobdiff_plain;f=binding%2Fmdsal-binding-api%2Fsrc%2Fmain%2Fjava%2Forg%2Fopendaylight%2Fmdsal%2Fbinding%2Fapi%2FWriteTransaction.java;h=89be6fbb6e3f2622c16f2894077fbe11443122e7;hb=a097ce084ca81e5b2f2ccbf15cf37e29511083f5;hp=d9d029a0979e1e70fef3ae5446c37ef43cd69ab5;hpb=104afbbc04792df68ee001c14fb02171d640f889;p=mdsal.git diff --git a/binding/mdsal-binding-api/src/main/java/org/opendaylight/mdsal/binding/api/WriteTransaction.java b/binding/mdsal-binding-api/src/main/java/org/opendaylight/mdsal/binding/api/WriteTransaction.java index d9d029a097..89be6fbb6e 100644 --- a/binding/mdsal-binding-api/src/main/java/org/opendaylight/mdsal/binding/api/WriteTransaction.java +++ b/binding/mdsal-binding-api/src/main/java/org/opendaylight/mdsal/binding/api/WriteTransaction.java @@ -7,135 +7,443 @@ */ package org.opendaylight.mdsal.binding.api; -import org.opendaylight.mdsal.common.api.AsyncWriteTransaction; -import org.opendaylight.mdsal.common.api.LogicalDatastoreType; - -import org.opendaylight.yangtools.yang.binding.DataObject; -import org.opendaylight.yangtools.yang.binding.InstanceIdentifier; +import com.google.common.util.concurrent.FluentFuture; +import edu.umd.cs.findbugs.annotations.CheckReturnValue; +import org.eclipse.jdt.annotation.NonNull; +import org.opendaylight.mdsal.common.api.CommitInfo; +import org.opendaylight.mdsal.common.api.DataValidationFailedException; +import org.opendaylight.mdsal.common.api.OptimisticLockFailedException; +import org.opendaylight.mdsal.common.api.TransactionCommitFailedException; /** * A transaction that provides mutation capabilities on a data tree. * *
- * For more information on usage and examples, please see the documentation in {@link AsyncWriteTransaction}. + * 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 #commit} on the transaction. This seals the transaction (preventing any further writes using this + * transaction) and commits 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. + * + *
+ * Implementation Note: This interface is not intended to be implemented by users of MD-SAL, but only to be
+ * consumed by them.
*/
-public interface WriteTransaction extends AsyncWriteTransaction
- * This method does not automatically create missing parent nodes. It is equivalent to invoking
- * {@link #put(LogicalDatastoreType, InstanceIdentifier, DataObject, boolean)}
- * with
- * 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
+ * @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
- */
-
- * For more information on usage and examples, please see the documentation
- * in {@link AsyncWriteTransaction}.
+ * Transaction may fail because of multiple reasons, such as
+ *
- * 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 true, any missing parent nodes will be automatically created
- * using a merge operation.
- * @throws IllegalStateException
- * if the transaction has already been submitted
+ * A successful commit produces implementation-specific {@link CommitInfo} structure, which is used to communicate
+ * post-condition information to the caller. Such information can contain commit-id, timing information or any
+ * other information the implementation wishes to share.
+ *
+ * @return a FluentFuture containing the result of the commit information. 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 already committed or was canceled.
*/
- 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).
*
- * 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 true, any missing parent nodes will be automatically
- * created using a merge operation.
- * @throws IllegalStateException
- * if the transaction has already been submitted
- */
- 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.
*
*