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.common.api.data;
10 import org.opendaylight.yangtools.concepts.ListenerRegistration;
11 import org.opendaylight.yangtools.concepts.Path;
15 * Base interface that provides access to a conceptual data tree store and also provides the ability to
16 * subscribe for changes to data under a given branch of the tree.
19 * All operations on the data tree are performed via one of the transactions:
21 * <li>Read-Only - allocated using {@link #newReadOnlyTransaction()}
22 * <li>Write-Only - allocated using {@link #newWriteOnlyTransaction()}
23 * <li>Read-Write - allocated using {@link #newReadWriteTransaction()}
27 * These transactions provide a stable isolated view of data tree, which is
28 * guaranteed to be not affected by other concurrent transactions, until
29 * transaction is committed.
32 * For a detailed explanation of how transaction are isolated and how transaction-local
33 * changes are committed to global data tree, see
34 * {@link AsyncReadTransaction}, {@link AsyncWriteTransaction},
35 * {@link AsyncReadWriteTransaction} and {@link AsyncWriteTransaction#commit()}.
39 * It is strongly recommended to use the type of transaction, which
40 * provides only the minimal capabilities you need. This allows for
41 * optimizations at the data broker / data store level. For example,
42 * implementations may optimize the transaction for reading if they know ahead
43 * of time that you only need to read data - such as not keeping additional meta-data,
44 * which may be required for write transactions.
47 * <b>Implementation Note:</b> This interface is not intended to be implemented
48 * by users of MD-SAL, but only to be consumed by them.
51 * Type of path (subtree identifier), which represents location in
54 * Type of data (payload), which represents data payload
56 public interface AsyncDataBroker<P extends Path<P>, D, L extends AsyncDataChangeListener<P, D>> extends //
57 AsyncDataTransactionFactory<P, D> {
61 * Scope of Data Change
64 * Represents scope of data change (addition, replacement, deletion).
66 * The terminology for scope types is reused from LDAP.
70 * Following is an example model with comments describing what notifications
71 * you would receive based on the scope you specify, when you are
72 * registering for changes on container a.
75 * container a // scope BASE, ONE, SUBTREE
76 * leaf "foo" // scope ONE, SUBTREE
77 * container // scope ONE, SUBTREE
78 * leaf "bar" // scope SUBTREE
79 * list list // scope ONE, SUBTREE
80 * list [a] // scope SUBTREE
81 * id "a" // scope SUBTREE
82 * list [b] // scope SUBTREE
83 * id "b" // scope SUBTREE
86 * Following is an example model with comments describing what notifications
87 * you would receive based on the scope you specify, when you are
88 * registering for changes on list list (without specifying concrete item in
92 * list list // scope BASE, ONE, SUBTREE
93 * list [a] // scope ONE, SUBTREE
94 * id "a" // scope SUBTREE
95 * list [b] // scope ONE, SUBTREE
96 * id "b" // scope SUBTREE
100 * @see http://www.idevelopment.info/data/LDAP/LDAP_Resources/
101 * SEARCH_Setting_the_SCOPE_Parameter.shtml
103 enum DataChangeScope {
106 * Represents only a direct change of the node, such as replacement of a node, addition or
107 * deletion. Note that, as described in {@link #ONE}, this may have counterintuitive
108 * interactions when viewed from a <i>binding aware</i> application, in particular when it
114 * Represent a change (addition,replacement,deletion) of the node or one of its direct
117 * Note that this is done in the <i>binding independent</i> data tree and so the behavior
118 * might be counterintuitive when used with <i>binding aware</i> interfaces particularly
119 * when it comes to lists. The list itself is a node in the <i>binding independent</i> tree,
120 * which means that if you want to listen on new elements you must listen on the list itself
121 * with the scope of {@link #ONE}.
123 * As an example, in the below YANG snippet, listening on <tt>node</tt> with scope
124 * {@link #ONE} would tell you if the <tt>node-connector</tt> list was created or deleted,
125 * but not when elements were added or removed from the list assuming the list itself
135 * list node-connector {
144 * This scope is superset of {@link #BASE}.
149 * Represents a change of the node or any of or any of its child nodes,
152 * This scope is superset of {@link #ONE} and {@link #BASE}.
162 AsyncReadOnlyTransaction<P, D> newReadOnlyTransaction();
168 AsyncReadWriteTransaction<P, D> newReadWriteTransaction();
174 AsyncWriteTransaction<P, D> newWriteOnlyTransaction();
177 * Registers a {@link AsyncDataChangeListener} to receive
178 * notifications when data changes under a given path in the conceptual data
181 * You are able to register for notifications for any node or subtree
182 * which can be reached via the supplied path.
184 * If path type <code>P</code> allows it, you may specify paths up to the leaf nodes
185 * then it is possible to listen on leaf nodes.
187 * You are able to register for data change notifications for a subtree even
188 * if it does not exist. You will receive notification once that node is
191 * If there is any preexisting data in data tree on path for which you are
192 * registering, you will receive initial data change event, which will
193 * contain all preexisting data, marked as created.
196 * You are also able to specify the scope of the changes you want to be
199 * Supported scopes are:
201 * <li>{@link DataChangeScope#BASE} - notification events will only be
202 * triggered when a node referenced by path is created, removed or replaced.
203 * <li>{@link DataChangeScope#ONE} - notifications events will only be
204 * triggered when a node referenced by path is created, removed or replaced,
205 * or any or any of its immediate children are created, updated or removed.
206 * <li>{@link DataChangeScope#SUBTREE} - notification events will be
207 * triggered when a node referenced by the path is created, removed
208 * or replaced or any of the children in its subtree are created, removed
211 * See {@link DataChangeScope} for examples.
213 * This method returns a {@link ListenerRegistration} object. To
214 * "unregister" your listener for changes call the "close" method on this
217 * You MUST call close when you no longer need to receive notifications
218 * (such as during shutdown or for example if your bundle is shutting down).
221 * Logical Data Store - Logical Datastore you want to listen for
222 * changes in. For example
223 * {@link LogicalDatastoreType#OPERATIONAL} or
224 * {@link LogicalDatastoreType#CONFIGURATION}
226 * Path (subtree identifier) on which client listener will be
229 * Instance of listener which should be invoked on
230 * @param triggeringScope
231 * Scope of change which triggers callback.
232 * @return Listener registration object, which may be used to unregister
233 * your listener using {@link ListenerRegistration#close()} to stop
234 * delivery of change events.
236 ListenerRegistration<L> registerDataChangeListener(LogicalDatastoreType store, P path, L listener,
237 DataChangeScope triggeringScope);