1 /*
2  * Copyright (C) 2019 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 
17 package android.timezone;
18 
19 import android.annotation.NonNull;
20 import android.annotation.Nullable;
21 
22 import com.android.internal.annotations.GuardedBy;
23 
24 import java.util.Objects;
25 
26 /**
27  * A class that can find time zone-related information about telephony networks.
28  *
29  * @hide
30  */
31 public final class TelephonyLookup {
32 
33     private static final Object sLock = new Object();
34     @GuardedBy("sLock")
35     private static TelephonyLookup sInstance;
36 
37     /**
38      * Obtains an instance for use when resolving telephony time zone information.
39      */
40     @NonNull
getInstance()41     public static TelephonyLookup getInstance() {
42         synchronized (sLock) {
43             if (sInstance == null) {
44                 sInstance = new TelephonyLookup(libcore.timezone.TelephonyLookup.getInstance());
45             }
46             return sInstance;
47         }
48     }
49 
50     @NonNull
51     private final libcore.timezone.TelephonyLookup mDelegate;
52 
TelephonyLookup(@onNull libcore.timezone.TelephonyLookup delegate)53     private TelephonyLookup(@NonNull libcore.timezone.TelephonyLookup delegate) {
54         mDelegate = Objects.requireNonNull(delegate);
55     }
56 
57     /**
58      * Returns an object capable of querying telephony network information. This method can return
59      * {@code null} in the event of an error while reading the underlying data files.
60      */
61     @Nullable
getTelephonyNetworkFinder()62     public TelephonyNetworkFinder getTelephonyNetworkFinder() {
63         libcore.timezone.TelephonyNetworkFinder telephonyNetworkFinderDelegate =
64                 mDelegate.getTelephonyNetworkFinder();
65         return telephonyNetworkFinderDelegate != null
66                 ? new TelephonyNetworkFinder(telephonyNetworkFinderDelegate) : null;
67     }
68 }
69