1 /*
2  * Copyright (C) 2020 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 package android.os;
17 
18 import android.annotation.NonNull;
19 import android.annotation.Nullable;
20 import android.annotation.SystemApi;
21 import android.annotation.SystemApi.Client;
22 
23 /**
24  * Provides a way to register and obtain the system service binder objects managed by the stats
25  * service.
26  *
27  * <p> Only the statsd mainline module will be able to access an instance of this class.
28  * @hide
29  */
30 @SystemApi(client = Client.MODULE_LIBRARIES)
31 public class StatsServiceManager {
32     /**
33      * @hide
34      */
StatsServiceManager()35     public StatsServiceManager() {}
36 
37     /**
38      * A class that exposes the methods to register and obtain each system service.
39      */
40     public static final class ServiceRegisterer {
41         private final String mServiceName;
42 
43         /**
44          * @hide
45          */
ServiceRegisterer(String serviceName)46         public ServiceRegisterer(String serviceName) {
47             mServiceName = serviceName;
48         }
49 
50         /**
51          * Get the system server binding object for StatsManagerService.
52          *
53          * <p> This blocks until the service instance is ready.
54          * or a timeout happens, in which case it returns null.
55          */
56         @Nullable
get()57         public IBinder get() {
58             return ServiceManager.getService(mServiceName);
59         }
60 
61         /**
62          * Get the system server binding object for a service.
63          *
64          * <p>This blocks until the service instance is ready,
65          * or a timeout happens, in which case it throws {@link ServiceNotFoundException}.
66          */
67         @Nullable
getOrThrow()68         public IBinder getOrThrow() throws ServiceNotFoundException {
69             try {
70                 return ServiceManager.getServiceOrThrow(mServiceName);
71             } catch (ServiceManager.ServiceNotFoundException e) {
72                 throw new ServiceNotFoundException(mServiceName);
73             }
74         }
75 
76         /**
77          * Get the system server binding object for a service. If the specified service is
78          * not available, it returns null.
79          */
80         @Nullable
tryGet()81         private IBinder tryGet() {
82             return ServiceManager.checkService(mServiceName);
83         }
84     }
85 
86     /**
87      * See {@link ServiceRegisterer#getOrThrow()}
88      */
89     public static class ServiceNotFoundException extends ServiceManager.ServiceNotFoundException {
90         /**
91          * Constructor
92          *
93          * @param name the name of the binder service that cannot be found.
94          */
ServiceNotFoundException(@onNull String name)95         public ServiceNotFoundException(@NonNull String name) {
96             super(name);
97         }
98     }
99 
100     /**
101      * Returns {@link ServiceRegisterer} for the "statscompanion" service.
102      */
103     @NonNull
getStatsCompanionServiceRegisterer()104     public ServiceRegisterer getStatsCompanionServiceRegisterer() {
105         return new ServiceRegisterer("statscompanion");
106     }
107 
108     /**
109      * Returns {@link ServiceRegisterer} for the "statsmanager" service.
110      */
111     @NonNull
getStatsManagerServiceRegisterer()112     public ServiceRegisterer getStatsManagerServiceRegisterer() {
113         return new ServiceRegisterer("statsmanager");
114     }
115 
116     /**
117      * Returns {@link ServiceRegisterer} for the "statsd" service.
118      */
119     @NonNull
getStatsdServiceRegisterer()120     public ServiceRegisterer getStatsdServiceRegisterer() {
121         return new ServiceRegisterer("stats");
122     }
123 }
124