/* * Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved. * * This program and the accompanying materials are made available under the * terms of the Eclipse Public License v1.0 which accompanies this distribution, * and is available at http://www.eclipse.org/legal/epl-v10.html */ package org.opendaylight.mdsal.binding.api; /** * A transaction that provides a stateful read-only view of the data tree. * *
* View of the data tree is a stable point-in-time snapshot of the current data tree state when the * transaction was created. It's state and underlying data tree is not affected by other * concurrently running transactions. * *
* Implementation Note: This interface is not intended to be implemented by users of MD-SAL, * but only to be consumed by them. * *
PATH
is A
.
*
*
* txRead = broker.newReadOnlyTransaction(); // read Transaction is snapshot of data
* txWrite = broker.newReadWriteTransactoin(); // concurrent write transaction
* txRead.read(OPERATIONAL, PATH).get(); // will return Optional containing A
* txWrite = broker.put(OPERATIONAL, PATH, B); // writes B to PATH
* txRead.read(OPERATIONAL, PATH).get(); // still returns Optional containing A
* txWrite.submit().get(); // data tree is updated, PATH contains B
* txRead.read(OPERATIONAL, PATH).get(); // still returns Optional containing A
* txAfterCommit = broker.newReadOnlyTransaction(); // read Transaction is snapshot of new state
* txAfterCommit.read(OPERATIONAL, PATH).get(); // returns Optional containing B;
*
*
* * Note: example contains blocking calls on future only to illustrate that action happened after other * asynchronous action. Use of blocking call {@link com.google.common.util.concurrent.FluentFuture#get()} is * discouraged for most uses and you should use * {@link com.google.common.util.concurrent.FluentFuture#addCallback(com.google.common.util.concurrent.FutureCallback, * java.util.concurrent.Executor)} or other functions from {@link com.google.common.util.concurrent.Futures} to register * more specific listeners. */ public interface ReadTransaction extends Transaction, AutoCloseable, ReadOperations { /** * Closes this transaction and releases all resources associated with it. */ @Override void close(); }