2 * Copyright (c) 2018 Pantheon Technologies, s.r.o. 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.util.concurrent.FluentFuture;
11 import com.google.common.util.concurrent.MoreExecutors;
12 import java.util.Optional;
13 import org.eclipse.jdt.annotation.NonNull;
14 import org.opendaylight.mdsal.common.api.LogicalDatastoreType;
15 import org.opendaylight.mdsal.common.api.ReadFailedException;
16 import org.opendaylight.yangtools.yang.binding.DataObject;
17 import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
20 * Read-like operations supported by {@link ReadTransaction} and {@link ReadWriteTransaction}. This interface defines
21 * the operations without a tie-in with lifecycle management.
23 public interface ReadOperations {
25 * Reads data from the provided logical data store located at the provided path.
28 * If the target is a subtree, then the whole subtree is read (and will be accessible from the returned data
31 * @param store Logical data store from which read should occur.
32 * @param path Path which uniquely identifies subtree which client want to read
33 * @return a FluentFuture containing the result of the read. The Future blocks until the operation is complete. Once
36 * <li>If the data at the supplied path exists, the Future returns an Optional object containing the data.
38 * <li>If the data at the supplied path does not exist, the Future returns Optional.empty().</li>
39 * <li>If the read of the data fails, the Future will fail with a {@link ReadFailedException} or
40 * an exception derived from ReadFailedException.</li>
42 * @throws NullPointerException if any of the arguments is null
43 * @throws IllegalArgumentException if the path is {@link InstanceIdentifier#isWildcarded()}
45 <T extends DataObject> @NonNull FluentFuture<Optional<T>> read(@NonNull LogicalDatastoreType store,
46 @NonNull InstanceIdentifier<T> path);
49 * Determines if data data exists in the provided logical data store located at the provided path.
52 * Default implementation just delegates to {@link #read(LogicalDatastoreType, InstanceIdentifier)}. Implementations
53 * are recommended to override with a more efficient implementation.
55 * @param store Logical data store from which read should occur.
56 * @param path Path which uniquely identifies subtree which client want to read
57 * @return a FluentFuture containing the result of the check. The Future blocks until the operation is complete.
60 * <li>If the data at the supplied path exists, the Future returns {@link Boolean#TRUE}.
62 * <li>If the data at the supplied path does not exist, the Future returns {@link Boolean#FALSE}.</li>
63 * <li>If the check fails, the Future will fail with a {@link ReadFailedException} or an exception derived
64 * from ReadFailedException.</li>
66 * @throws NullPointerException if any of the arguments is null
67 * @throws IllegalArgumentException if the path is {@link InstanceIdentifier#isWildcarded()} and the implementation
68 * does not support evaluating wildcards.
70 default @NonNull FluentFuture<Boolean> exists(final @NonNull LogicalDatastoreType store,
71 final @NonNull InstanceIdentifier<?> path) {
72 return read(store, path).transform(Optional::isPresent, MoreExecutors.directExecutor());