X-Git-Url: https://git.opendaylight.org/gerrit/gitweb?p=controller.git;a=blobdiff_plain;f=opendaylight%2Fmd-sal%2Fsal-common-api%2Fsrc%2Fmain%2Fjava%2Forg%2Fopendaylight%2Fcontroller%2Fmd%2Fsal%2Fcommon%2Fapi%2Fdata%2FAsyncWriteTransaction.java;h=effeabefae89a69158d73028cc9467fb47f9a896;hp=35b9914a120dc289dbac3ff8c8f7ae85176f5be4;hb=690b4c7632f05f7f1ba23e45ce2d00a2e82d22c1;hpb=88f3fac27f5dbc4043cdeadacaca34bd6f57c854 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 35b9914a12..effeabefae 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 @@ -7,113 +7,314 @@ */ package org.opendaylight.controller.md.sal.common.api.data; -import java.util.concurrent.Future; - import org.opendaylight.controller.md.sal.common.api.TransactionStatus; import org.opendaylight.yangtools.concepts.Path; import org.opendaylight.yangtools.yang.common.RpcResult; -public interface AsyncWriteTransaction

, D> extends AsyncTransaction { +import com.google.common.util.concurrent.CheckedFuture; +import com.google.common.util.concurrent.ListenableFuture; + +/** + * 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. + * + *

Put operation

+ * Stores a piece of data at a specified path. This acts as an add / replace + * operation, which is to say that whole subtree will be replaced by the + * specified data. + *

+ * Performing the following put operations: + * + * 

+ * 1) container { list [ a ] }
+ * 2) container { list [ b ] }
+ *
+ * + * will result in the following data being present: + * + * 
+ * container { list [ b ] }
+ *
+ *

Merge operation

+ * Merges a piece of data with the existing data at a specified path. 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. + * + *

Delete operation

+ * Removes a piece of data from a specified path. + *

+ * 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 + * Type of data (payload), which represents data payload + */ +public interface AsyncWriteTransaction

, 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 #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. * - * container { list [ a, b ] } + *

Example usage:

+ * 
+     *  private void doWrite( final int tries ) {
+     *      WriteTransaction writeTx = dataBroker.newWriteOnlyTransaction();
      *
-     * This also means that storing the container will preserve any augmentations
-     * which have been attached to it.
+     *      MyDataObject data = ...;
+     *      InstanceIdentifier<MyDataObject> path = ...;
+     *      writeTx.put( LogicalDatastoreType.OPERATIONAL, path, data );
      *
-     * If you require an explicit replace operation, use {@link #put(LogicalDatastoreType, Path, Object)} instead.
+     *      Futures.addCallback( writeTx.submit(), new FutureCallback<Void>() {
+     *          public void onSuccess( Void result ) {
+     *              // succeeded
+     *          }
      *
-     * @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.
+     *          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

+ *

+ * Transaction may fail because of multiple reasons, such as + *

* - * @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); - - /** + *

Change compatibility

* - * Closes transaction and resources allocated to the transaction. + * 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. * - * This call does not change Transaction status. Client SHOULD - * explicitly {@link #commit()} or {@link #cancel()} transaction. + *

Change compatibility of leafs, leaf-list items

* - * @throws IllegalStateException if the transaction has not been - * updated by invoking {@link #commit()} or {@link #cancel()}. + * 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 stateTx 1Tx 2Result
Emptyput(A,1)put(A,2)Tx 2 will fail, state is A=1
Emptyput(A,1)merge(A,2)A=2
Emptymerge(A,1)put(A,2)Tx 2 will fail, state is A=1
Emptymerge(A,1)merge(A,2)A=2
A=0put(A,1)put(A,2)Tx 2 will fail, A=1
A=0put(A,1)merge(A,2)A=2
A=0merge(A,1)put(A,2)Tx 2 will fail, A=1
A=0merge(A,1)merge(A,2)A=2
A=0delete(A)put(A,2)Tx 2 will fail, A does not exists
A=0delete(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 stateTx 1Tx 2Result
Emptyput(TOP,[])put(TOP,[])Tx 2 will fail, state is TOP=[]
Emptyput(TOP,[])merge(TOP,[])TOP=[]
Emptyput(TOP,[FOO=1])put(TOP,[BAR=1])Tx 2 will fail, state is TOP=[FOO=1]
Emptyput(TOP,[FOO=1])merge(TOP,[BAR=1])TOP=[FOO=1,BAR=1]
Emptymerge(TOP,[FOO=1])put(TOP,[BAR=1])Tx 2 will fail, state is TOP=[FOO=1]
Emptymerge(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 submit(); /** - * Initiates a commit of modification. This call logically seals the - * transaction, preventing any the client from interacting with the - * data stores. The transaction is marked as {@link TransactionStatus#SUBMITED} - * and enqueued into the data store backed for processing. - * - *

- * 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} or - * {@link TransactionStatus#FAILED} is reached. - * @throws IllegalStateException if the transaction is not {@link TransactionStatus#NEW} + * @deprecated Use {@link #submit()} instead. */ - public Future> commit(); + @Deprecated + ListenableFuture> commit(); }