1/*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16package android.databinding;
17
18import java.util.Map;
19
20/**
21 * A {@link Map} that notifies when items change. This kind of Map may be data bound
22 * and have the UI update as the map changes.
23 * <p>
24 * Implementers must call {@link OnMapChangedCallback#onMapChanged(ObservableMap, Object)} whenever
25 * an item is added, changed, or removed.
26 * <p>
27 * ObservableArrayMap is a convenient implementation of ObservableMap.
28 * MapChangeRegistry may help other implementations manage the callbacks.
29 * @see Observable
30 * @see ObservableList
31 */
32public interface ObservableMap<K, V> extends Map<K, V> {
33
34    /**
35     * Adds a callback to listen for changes to the ObservableMap.
36     * @param callback The callback to start listening for events.
37     */
38    void addOnMapChangedCallback(
39            OnMapChangedCallback<? extends ObservableMap<K, V>, K, V> callback);
40
41    /**
42     * Removes a previously added callback.
43     * @param callback The callback that no longer needs to be notified of map changes.
44     */
45    void removeOnMapChangedCallback(
46            OnMapChangedCallback<? extends ObservableMap<K, V>, K, V> callback);
47
48    /**
49     * A callback receiving notifications when an ObservableMap changes.
50     */
51    abstract class OnMapChangedCallback<T extends ObservableMap<K, V>, K, V> {
52
53        /**
54         * Called whenever an ObservableMap changes, including values inserted, deleted,
55         * and changed.
56         * @param sender The changing map.
57         * @param key The key of the value inserted, removed, or changed.
58         */
59        public abstract void onMapChanged(T sender, K key);
60    }
61}
62