1 /* 2 * Copyright (C) 2016 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.os.health; 18 19 import android.content.Context; 20 import android.os.BatteryStats; 21 import android.os.Process; 22 import android.os.RemoteException; 23 import android.os.ServiceManager; 24 25 import com.android.internal.app.IBatteryStats; 26 27 /** 28 * Provides access to data about how various system resources are used by applications. 29 * @more 30 * <p> 31 * If you are going to be using this class to log your application's resource usage, 32 * please consider the amount of resources (battery, network, etc) that will be used 33 * by the logging itself. It can be substantial. 34 * <p> 35 * <b>Battery Usage</b><br> 36 * The statistics related to power (battery) usage are recorded since the device 37 * was last unplugged. It is expected that applications schedule more work to do 38 * while the device is plugged in (e.g. using {@link android.app.job.JobScheduler 39 * JobScheduler}), and while that can affect charging rates, it is still preferable 40 * to actually draining the battery. 41 */ 42 public class SystemHealthManager { 43 private final IBatteryStats mBatteryStats; 44 45 /** 46 * Construct a new SystemHealthManager object. 47 * @hide 48 */ SystemHealthManager()49 public SystemHealthManager() { 50 mBatteryStats = IBatteryStats.Stub.asInterface( 51 ServiceManager.getService(BatteryStats.SERVICE_NAME)); 52 } 53 54 /** 55 * Obtain a SystemHealthManager object for the supplied context. 56 * 57 * @hide 58 */ from(Context context)59 public static SystemHealthManager from(Context context) { 60 return (SystemHealthManager)context.getSystemService(Context.SYSTEM_HEALTH_SERVICE); 61 } 62 63 /** 64 * Return a {@link HealthStats} object containing a snapshot of system health 65 * metrics for the given uid (user-id, which in usually corresponds to application). 66 * @more 67 * 68 * An application must hold the {@link android.Manifest.permission#BATTERY_STATS 69 * android.permission.BATTERY_STATS} permission in order to retrieve any HealthStats 70 * other than its own. 71 * 72 * @param uid User ID for a given application. 73 * @return A {@link HealthStats} object containing the metrics for the requested 74 * application. The keys for this HealthStats object will be from the {@link UidHealthStats} 75 * class. 76 * @see Process#myUid() Process.myUid() 77 */ takeUidSnapshot(int uid)78 public HealthStats takeUidSnapshot(int uid) { 79 try { 80 final HealthStatsParceler parceler = mBatteryStats.takeUidSnapshot(uid); 81 return parceler.getHealthStats(); 82 } catch (RemoteException ex) { 83 throw new RuntimeException(ex); 84 } 85 } 86 87 /** 88 * Return a {@link HealthStats} object containing a snapshot of system health 89 * metrics for the application calling this API. This method is the same as calling 90 * {@code takeUidSnapshot(Process.myUid())}. 91 * 92 * @return A {@link HealthStats} object containing the metrics for this application. The keys 93 * for this HealthStats object will be from the {@link UidHealthStats} class. 94 */ takeMyUidSnapshot()95 public HealthStats takeMyUidSnapshot() { 96 return takeUidSnapshot(Process.myUid()); 97 } 98 99 /** 100 * Return a {@link HealthStats} object containing a snapshot of system health 101 * metrics for the given uids (user-id, which in usually corresponds to application). 102 * @more 103 * 104 * An application must hold the {@link android.Manifest.permission#BATTERY_STATS 105 * android.permission.BATTERY_STATS} permission in order to retrieve any HealthStats 106 * other than its own. 107 * 108 * @param uids An array of User IDs to retrieve. 109 * @return An array of {@link HealthStats} objects containing the metrics for each of 110 * the requested uids. The keys for this HealthStats object will be from the 111 * {@link UidHealthStats} class. 112 */ takeUidSnapshots(int[] uids)113 public HealthStats[] takeUidSnapshots(int[] uids) { 114 try { 115 final HealthStatsParceler[] parcelers = mBatteryStats.takeUidSnapshots(uids); 116 final HealthStats[] results = new HealthStats[uids.length]; 117 final int N = uids.length; 118 for (int i=0; i<N; i++) { 119 results[i] = parcelers[i].getHealthStats(); 120 } 121 return results; 122 } catch (RemoteException ex) { 123 throw new RuntimeException(ex); 124 } 125 } 126 127 } 128 129