2 * Copyright (c) 2015 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.dom.api;
10 import com.google.common.annotations.Beta;
11 import com.google.common.util.concurrent.CheckedFuture;
12 import javax.annotation.Nonnull;
13 import org.opendaylight.mdsal.common.api.DataValidationFailedException;
14 import org.opendaylight.mdsal.common.api.PostCanCommitStep;
15 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidate;
16 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
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 DOMDataTreeCommitCohort}s are hooked up into commit of data tree changes and MAY
27 * negatively affect performance of data broker / store.
29 * Implementations of this interface are discouraged, unless you really need ability to veto data
30 * 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 {@link DataTreeCandidate} and
36 * provided {@link SchemaContext} for validation purposes.
38 * Use of any other external mutable state is discouraged, implementation MUST NOT use any
39 * transaction related APIs on same data broker / data store instance during invocation of
40 * callbacks, except ones provided as argument. Note that this MAY BE enforced by some
41 * implementations of {@link DOMDataBroker} or DOMDataCommitCoordinator
43 * Note that this may be enforced by some implementations of {@link DOMDataTreeCommitCohortRegistry}
44 * and such calls may fail.
46 * <h3>Correct model usage</h3> If implementation is performing YANG-model driven validation
47 * implementation SHOULD use provided schema context.
49 * Any other instance of {@link SchemaContext} obtained by other means, may not be valid for
50 * associated DataTreeCandidate and it may lead to incorrect validation or processing of provided
53 * <h3>DataTreeCandidate assumptions</h3> Implementation SHOULD NOT make any assumptions on
54 * {@link DataTreeCandidate} being successfully committed until associated
55 * {@link PostCanCommitStep#preCommit()} and
56 * {@link org.opendaylight.mdsal.common.api.PostPreCommitStep#commit()} callback was invoked.
59 * <h2>Usage patterns</h2>
61 * <h3>Data Tree Validator</h3>
63 * Validator is implementation, which only validates {@link DataTreeCandidate} and does not retain
64 * any state derived from edited data - does not care if {@link DataTreeCandidate} was rejected
65 * afterwards or transaction was cancelled.
67 * Implementation may opt-out from receiving {@code preCommit()}, {@code commit()}, {@code abort()}
68 * callbacks by returning {@link PostCanCommitStep#NOOP}.
70 * TODO: Provide example and describe more usage patterns
72 * @author Tony Tkacik <ttkacik@cisco.com>
76 public interface DOMDataTreeCommitCohort {
79 * Validates supplied data tree candidate and associates cohort-specific steps with data broker
82 * If {@link DataValidationFailedException} is thrown by implementation, commit of supplied data
83 * will be prevented, with the DataBroker transaction providing the thrown exception as the
86 * Note the implementations are expected to do validation and processing asynchronous.
88 * Implementations SHOULD do processing fast, and are discouraged SHOULD NOT block on any
91 * Implementation MUST NOT access any data transaction related APIs during invocation of
92 * callback. Note that this may be enforced by some implementations of
93 * {@link DOMDataTreeCommitCohortRegistry} and such calls may fail.
95 * Implementation MAY opt-out from implementing other steps by returning
96 * {@link PostCanCommitStep#NOOP}. Otherwise implementation MUST return instance of
97 * {@link PostCanCommitStep}, which will be used to invoke
98 * {@link org.opendaylight.mdsal.common.api.PostPreCommitStep#commit()} or
99 * {@link PostCanCommitStep#abort()} based on accepting data by data broker and or other commit
102 * @param txId Transaction identifier. SHOULD be used only for reporting and correlation.
103 * Implementation MUST NOT use {@code txId} for validation.
104 * @param candidate Data Tree candidate to be validated and committed.
105 * @param ctx Schema Context to which Data Tree candidate should conform.
106 * @return Checked future which will successfully complete with user-supplied implementation of
107 * {@link PostCanCommitStep} if data are valid, or failed check future with
108 * {@link DataValidationFailedException} if and only if provided
109 * {@link DOMDataTreeCandidate} did not pass validation. Users are encouraged to use
110 * more specific subclasses of this exception to provide additional information about
111 * validation failure reason.
114 CheckedFuture<PostCanCommitStep, DataValidationFailedException> canCommit(@Nonnull Object txId,
115 @Nonnull DOMDataTreeCandidate candidate, @Nonnull SchemaContext ctx);