1/*
2 * Copyright 2018 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 androidx.core.app;
18
19import android.app.Activity;
20import android.app.AppComponentFactory;
21import android.app.Application;
22import android.app.Service;
23import android.content.BroadcastReceiver;
24import android.content.ContentProvider;
25import android.content.Intent;
26
27import androidx.annotation.RequiresApi;
28import androidx.annotation.RestrictTo;
29
30/**
31 * Instance of AppComponentFactory for support libraries.
32 * @see CompatWrapped
33 * @hide
34 */
35@RequiresApi(api = 28)
36@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
37public class CoreComponentFactory extends AppComponentFactory {
38    private static final String TAG = "CoreComponentFactory";
39
40    @Override
41    public Activity instantiateActivity(ClassLoader cl, String className, Intent intent)
42            throws InstantiationException, IllegalAccessException, ClassNotFoundException {
43        return checkCompatWrapper(super.instantiateActivity(cl, className, intent));
44    }
45
46    @Override
47    public Application instantiateApplication(ClassLoader cl, String className)
48            throws InstantiationException, IllegalAccessException, ClassNotFoundException {
49        return checkCompatWrapper(super.instantiateApplication(cl, className));
50    }
51
52    @Override
53    public BroadcastReceiver instantiateReceiver(ClassLoader cl, String className,
54            Intent intent)
55            throws InstantiationException, IllegalAccessException, ClassNotFoundException {
56        return checkCompatWrapper(super.instantiateReceiver(cl, className, intent));
57    }
58
59    @Override
60    public ContentProvider instantiateProvider(ClassLoader cl, String className)
61            throws InstantiationException, IllegalAccessException, ClassNotFoundException {
62        return checkCompatWrapper(super.instantiateProvider(cl, className));
63    }
64
65    @Override
66    public Service instantiateService(ClassLoader cl, String className, Intent intent)
67            throws InstantiationException, IllegalAccessException, ClassNotFoundException {
68        return checkCompatWrapper(super.instantiateService(cl, className, intent));
69    }
70
71    static <T> T checkCompatWrapper(T obj) {
72        if (obj instanceof CompatWrapped) {
73            T wrapper = (T) ((CompatWrapped) obj).getWrapper();
74            if (wrapper != null) {
75                return wrapper;
76            }
77        }
78        return obj;
79    }
80
81    /**
82     * Implement this interface to allow a different class to be returned when instantiating
83     * on certain API levels.
84     * @hide
85     */
86    @RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
87    public interface CompatWrapped {
88        /**
89         * Called while this class is being instantiated by the OS.
90         *
91         * If an object is returned then it will be used in place of the class.
92         * Note: this will not be called on API <= 27.
93         *
94         * Example:
95         * <pre class="prettyprint">
96         * {@literal
97         * public AndroidXContentProvider extends ContentProvider implements CompatWrapped {
98         *     ...
99         *
100         *     public Object getWrapper() {
101         *         if (SDK_INT >= 29) {
102         *             return new AndroidXContentProviderV29(this);
103         *         }
104         *         return null;
105         *     }
106         * }
107         * }
108         * </pre>
109         */
110        Object getWrapper();
111    }
112
113}
114