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.controller.md.sal.binding.api;
10 import java.util.Collection;
11 import java.util.EventListener;
12 import javax.annotation.Nonnull;
13 import org.opendaylight.yangtools.yang.binding.DataObject;
16 * Interface implemented by classes interested in receiving notifications about
17 * data tree changes. This interface differs from {@link DataChangeListener}
18 * in that it provides a cursor-based view of the change, which has potentially
19 * lower overhead and allow more flexible consumption of change event.
22 * Note: this interface enables notifications only at the leader of the data store, if clustered. If you want
23 * notifications on all instances in a cluster, use the {@link ClusteredDataTreeChangeListener}.
25 public interface DataTreeChangeListener<T extends DataObject> extends EventListener {
27 * Invoked when there was data change for the supplied path, which was used
28 * to register this listener.
31 * This method may be also invoked during registration of the listener if
32 * there is any pre-existing data in the conceptual data tree for supplied
33 * path. This initial event will contain all pre-existing data as created.
36 * A data change event may be triggered spuriously, e.g. such that data before
37 * and after compare as equal. Implementations of this interface are expected
38 * to recover from such events. Event producers are expected to exert reasonable
39 * effort to suppress such events.
42 * In other words, it is completely acceptable to observe
43 * a {@link DataObjectModification}, while the state observed before and
44 * after- data items compare as equal.
46 * @param changes Collection of change events, may not be null or empty.
48 void onDataTreeChanged(@Nonnull Collection<DataTreeModification<T>> changes);