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.binding.api;
10 import java.util.List;
11 import org.eclipse.jdt.annotation.NonNull;
12 import org.opendaylight.yangtools.yang.binding.DataObject;
15 * Interface implemented by classes interested in receiving notifications about changes to a data tree. It provides
16 * a cursor-based view of the change, which has potentially lower overhead and allow more flexible consumption of change
19 public interface DataTreeChangeListener<T extends DataObject> {
21 * Invoked when there was data change for the supplied path, which was used to register this listener.
24 * This method may be also invoked during registration of the listener if there is any pre-existing data in the
25 * conceptual data tree for supplied path. This initial event will contain all pre-existing data as created.
28 * Note: If there is no pre-existing data, the method {@link #onInitialData} will be invoked.
31 * A data change event may be triggered spuriously, e.g. such that data before and after compare as equal.
32 * Implementations of this interface are expected to recover from such events. Event producers are expected to exert
33 * reasonable effort to suppress such events.
36 * In other words, it is completely acceptable to observe a {@link DataObjectModification}, while the state observed
37 * before and after- data items compare as equal.
39 * @param changes List of change events, may not be null or empty.
41 void onDataTreeChanged(@NonNull List<DataTreeModification<T>> changes);
44 * Invoked only once during registration of the listener if there was no data in the conceptual data tree for the
45 * supplied path, which was used to register this listener, and after this {@link #onDataTreeChanged(List)} would
46 * always be invoked for data changes.
49 * Default implementation does nothing and is appropriate for users who do not care about ascertaining initial
52 // FIXME: 14.0.0: this method should be non-default
53 default void onInitialData() {