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