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 com.google.common.base.Optional;
11 import com.google.common.util.concurrent.CheckedFuture;
12 import org.opendaylight.mdsal.common.api.AsyncReadTransaction;
13 import org.opendaylight.mdsal.common.api.LogicalDatastoreType;
14 import org.opendaylight.mdsal.common.api.ReadFailedException;
15 import org.opendaylight.yangtools.yang.binding.DataObject;
16 import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
20 * A transaction that provides a stateful read-only view of the data tree.
23 * For more information on usage and examples, please see the documentation in
24 * {@link org.opendaylight.mdsal.common.api.AsyncReadTransaction}.
26 public interface ReadTransaction extends AsyncReadTransaction<InstanceIdentifier<?>, DataObject> {
29 * Reads data from the provided logical data store located at the provided path.
32 * If the target is a subtree, then the whole subtree is read (and will be
33 * accessible from the returned data object).
36 * Logical data store from which read should occur.
38 * Path which uniquely identifies subtree which client want to
40 * @return a CheckFuture containing the result of the read. The Future blocks until the
41 * commit operation is complete. Once complete:
43 * <li>If the data at the supplied path exists, the Future returns an Optional object
44 * containing the data.</li>
45 * <li>If the data at the supplied path does not exist, the Future returns
46 * Optional#absent().</li>
47 * <li>If the read of the data fails, the Future will fail with a
48 * {@link ReadFailedException} or an exception derived from ReadFailedException.</li>
51 <T extends DataObject> CheckedFuture<Optional<T>,ReadFailedException> read(
52 LogicalDatastoreType store, InstanceIdentifier<T> path);