1/*
2 * Copyright (C) 2014 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 */
16
17package android.databinding;
18
19/**
20 * A convenience class that implements {@link android.databinding.Observable} interface and provides
21 * {@link #notifyPropertyChanged(int)} and {@link #notifyChange} methods.
22 */
23public class BaseObservable implements Observable {
24    private transient PropertyChangeRegistry mCallbacks;
25
26    public BaseObservable() {
27    }
28
29    @Override
30    public synchronized void addOnPropertyChangedCallback(OnPropertyChangedCallback callback) {
31        if (mCallbacks == null) {
32            mCallbacks = new PropertyChangeRegistry();
33        }
34        mCallbacks.add(callback);
35    }
36
37    @Override
38    public synchronized void removeOnPropertyChangedCallback(OnPropertyChangedCallback callback) {
39        if (mCallbacks != null) {
40            mCallbacks.remove(callback);
41        }
42    }
43
44    /**
45     * Notifies listeners that all properties of this instance have changed.
46     */
47    public synchronized void notifyChange() {
48        if (mCallbacks != null) {
49            mCallbacks.notifyCallbacks(this, 0, null);
50        }
51    }
52
53    /**
54     * Notifies listeners that a specific property has changed. The getter for the property
55     * that changes should be marked with {@link Bindable} to generate a field in
56     * <code>BR</code> to be used as <code>fieldId</code>.
57     *
58     * @param fieldId The generated BR id for the Bindable field.
59     */
60    public void notifyPropertyChanged(int fieldId) {
61        if (mCallbacks != null) {
62            mCallbacks.notifyCallbacks(this, fieldId, null);
63        }
64    }
65}
66