2 * Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
8 package org.opendaylight.mdsal.binding.api;
10 import org.opendaylight.yangtools.concepts.Registration;
13 * A chain of transactions. Transactions in a chain need to be committed in sequence and each transaction should see
14 * the effects of previous committed transactions as they occurred. A chain makes no guarantees of atomicity across
15 * the chained transactions - the transactions are committed as soon as possible in the order that they were committed.
16 * This behaviour is different from the default AsyncDataBroker, where a transaction is always created from the current
17 * global state, not taking into account any transactions previously committed by the calling thread. Due to
18 * the asynchronous nature of transaction submission this can lead to surprising results. If a thread executes
19 * the following sequence sufficiently quickly:
22 * AsyncWriteTransaction t1 = broker.newWriteOnlyTransaction();
26 * AsyncReadTransaction t2 = broker.newReadOnlyTransaction();
27 * Optional<?> maybeData = t2.read(id).get();
29 * it may happen, that it sees maybeData.isPresent() == false, simply because t1 has not completed the processes
30 * of being applied and t2 is actually allocated from the previous state. This is obviously bad for users who create
31 * incremental state in the datastore and actually read what they write in subsequent transactions. Using
32 * a TransactionChain instead of a broker solves this particular problem, and leads to expected behavior: t2 will always
33 * see the data written in t1 present.
35 public interface TransactionChain extends Registration, TransactionFactory {
37 * Create a new read only transaction which will continue the chain.
40 * The previous write transaction has to be either SUBMITTED ({@link WriteTransaction#commit commit} was invoked)
41 * or CANCELLED ({@link #close close} was invoked).
44 * The returned read-only transaction presents an isolated view of the data if the previous write transaction was
45 * successful - in other words, this read-only transaction will see the state changes made by the previous write
46 * transaction in the chain. However, state which was introduced by other transactions outside this transaction
47 * chain after creation of the previous transaction is not visible.
49 * @return New transaction in the chain.
50 * @throws IllegalStateException if the previous transaction was not SUBMITTED or CANCELLED.
51 * @throws TransactionChainClosedException if the chain has been closed.
54 ReadTransaction newReadOnlyTransaction();
57 * Create a new write-only transaction which will continue the chain.
60 * The previous write transaction has to be either SUBMITTED ({@link WriteTransaction#commit commit} was invoked)
61 * or CANCELLED ({@link #close close} was invoked)
64 * The returned write-only transaction presents an isolated view of the data if the previous write transaction was
65 * successful - in other words, this write-only transaction will see the state changes made by the previous write
66 * transaction in the chain. However, state which was introduced by other transactions outside this transaction
67 * chain after creation of the previous transaction is not visible
70 * Committing this write-only transaction using {@link WriteTransaction#commit commit} will commit the state
71 * changes in this transaction to be visible to any subsequent transaction in this chain and also to any transaction
74 * @return New transaction in the chain.
75 * @throws IllegalStateException if the previous transaction was not SUBMITTED or CANCELLED.
76 * @throws TransactionChainClosedException if the chain has been closed.
79 WriteTransaction newWriteOnlyTransaction();
82 * Create a new read-write transaction which will continue the chain.
85 * The previous write transaction has to be either SUBMITTED ({@link WriteTransaction#commit commit} was invoked)
86 * or CANCELLED ({@link #close close} was invoked).
89 * The returned read-write transaction presents an isolated view of the data if the previous write transaction was
90 * successful - in other words, this read-write transaction will see the state changes made by the previous write
91 * transaction in the chain. However, state which was introduced by other transactions outside this transaction
92 * chain after creation of the previous transaction is not visible.
95 * Committing this read-write transaction using {@link WriteTransaction#commit commit} will commit the state changes
96 * in this transaction to be visible to any subsequent transaction in this chain and also to any transaction outside
99 * @return New transaction in the chain.
100 * @throws IllegalStateException if the previous transaction was not SUBMITTED or CANCELLED.
101 * @throws TransactionChainClosedException if the chain has been closed.
104 ReadWriteTransaction newReadWriteTransaction();