2 * Copyright (c) 2016 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.annotations.Beta;
11 import com.google.common.util.concurrent.FluentFuture;
12 import edu.umd.cs.findbugs.annotations.CheckReturnValue;
13 import java.util.Collection;
14 import org.eclipse.jdt.annotation.NonNull;
15 import org.opendaylight.mdsal.common.api.DataValidationFailedException;
16 import org.opendaylight.mdsal.common.api.PostCanCommitStep;
17 import org.opendaylight.yangtools.yang.binding.DataObject;
20 * Commit cohort participating in commit of data modification, which can validate data tree
21 * modifications, with option to reject supplied modification, and with callbacks describing state
24 * <h2>Performance implications</h2>
26 * {@link DataTreeCommitCohort}s are hooked up into commit of data tree changes and MAY
27 * negatively affect performance of data broker / store.
30 * Implementations of this interface are discouraged, unless you really need ability to veto data
31 * tree changes, or to provide external state change in sync with visibility of commited data.
33 * <h2>Implementation requirements</h2>
35 * <h3>Correctness assumptions</h3> Implementation SHOULD use only provided
36 * {@link DataTreeModification} for validation purposes.
39 * Use of any other external mutable state is discouraged, implementation MUST NOT use any
40 * transaction related APIs on same data broker / data store instance during invocation of
41 * callbacks, except ones provided as argument. Note that this MAY BE enforced by some
42 * implementations of {@link DataBroker} or Commit coordinator
45 * Note that this may be enforced by some implementations of {@link DataTreeCommitCohortRegistry}
46 * and such calls may fail.
48 * <h3>DataTreeCandidate assumptions</h3> Implementation SHOULD NOT make any assumptions on
49 * {@link DataTreeModification} being successfully committed until associated
50 * {@link PostCanCommitStep#preCommit()} and
51 * {@link org.opendaylight.mdsal.common.api.PostPreCommitStep#commit()} callback was invoked.
53 * <h2>Usage patterns</h2>
55 * <h3>Data Tree Validator</h3>
58 * Validator is implementation, which only validates {@link DataTreeModification} and does not
59 * retain any state derived from edited data - does not care if {@link DataTreeModification} was
60 * rejected afterwards or transaction was cancelled.
63 * Implementation may opt-out from receiving {@code preCommit()}, {@code commit()}, {@code abort()}
64 * callbacks by returning {@link PostCanCommitStep#NOOP}.
67 * TODO: Provide example and describe more usage patterns
69 * @author Tony Tkacik <ttkacik@cisco.com>
72 public interface DataTreeCommitCohort<T extends DataObject> {
74 * Validates the supplied data tree modifications and associates the cohort-specific steps with data broker
78 * If {@link DataValidationFailedException} is thrown by implementation, the commit of the supplied data
79 * will be prevented, with the DataBroker transaction providing the thrown exception as the cause of failure.
82 * Note the implementations are expected to do validation and processing asynchronous. Implementations SHOULD do
83 * processing fast, and are discouraged from blocking on any external resources. Implementation MUST NOT access
84 * any data transaction related APIs during invocation of the callback. Note that this may be enforced by some
85 * implementations of {@link DataTreeCommitCohortRegistry} and such calls may fail.
88 * Implementation MAY opt-out from implementing other steps by returning
89 * {@link PostCanCommitStep#NOOP}. Otherwise implementation MUST return instance of
90 * {@link PostCanCommitStep}, which will be used to invoke
91 * {@link org.opendaylight.mdsal.common.api.PostPreCommitStep#commit()} or
92 * {@link PostCanCommitStep#abort()} based on accepting data by data broker and or other commit cohorts.
94 * @param txId Transaction identifier. SHOULD be used only for reporting and correlation.
95 * Implementation MUST NOT use {@code txId} for validation.
96 * @param modifications the {@link DataTreeModification}s to be validated and committed.
97 * @return a FluentFuture which will successfully complete with the user-supplied implementation of
98 * {@link PostCanCommitStep} if all candidates are valid, or a failed future with a
99 * {@link DataValidationFailedException} if and only if a provided
100 * {@link DataTreeModification} instance did not pass validation. Users are encouraged to use
101 * more specific subclasses of this exception to provide additional information about
102 * validation failure reason.
105 @NonNull FluentFuture<PostCanCommitStep> canCommit(@NonNull Object txId,
106 @NonNull Collection<DataTreeModification<T>> modifications);