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      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.annotation.SystemService;
     20 import android.content.Context;
     21 import android.os.BatteryStats;
     22 import android.os.Process;
     23 import android.os.RemoteException;
     24 import android.os.ServiceManager;
     25 import android.os.ServiceManager.ServiceNotFoundException;
     26 
     27 import com.android.internal.app.IBatteryStats;
     28 
     29 /**
     30  * Provides access to data about how various system resources are used by applications.
     31  * @more
     32  * <p>
     33  * If you are going to be using this class to log your application's resource usage,
     34  * please consider the amount of resources (battery, network, etc) that will be used
     35  * by the logging itself.  It can be substantial.
     36  * <p>
     37  * <b>Battery Usage</b><br>
     38  * The statistics related to power (battery) usage are recorded since the device
     39  * was last unplugged. It is expected that applications schedule more work to do
     40  * while the device is plugged in (e.g. using {@link android.app.job.JobScheduler
     41  * JobScheduler}), and while that can affect charging rates, it is still preferable
     42  * to actually draining the battery.
     43  */
     44 @SystemService(Context.SYSTEM_HEALTH_SERVICE)
     45 public class SystemHealthManager {
     46     private final IBatteryStats mBatteryStats;
     47 
     48     /**
     49      * Construct a new SystemHealthManager object.
     50      * @hide
     51      */
     52     public SystemHealthManager() {
     53         this(IBatteryStats.Stub.asInterface(ServiceManager.getService(BatteryStats.SERVICE_NAME)));
     54     }
     55 
     56     /** {@hide} */
     57     public SystemHealthManager(IBatteryStats batteryStats) {
     58         mBatteryStats = batteryStats;
     59     }
     60 
     61     /**
     62      * Obtain a SystemHealthManager object for the supplied context.
     63      *
     64      * @hide
     65      */
     66     public static SystemHealthManager from(Context context) {
     67         return (SystemHealthManager)context.getSystemService(Context.SYSTEM_HEALTH_SERVICE);
     68     }
     69 
     70     /**
     71      * Return a {@link HealthStats} object containing a snapshot of system health
     72      * metrics for the given uid (user-id, which in usually corresponds to application).
     73      * @more
     74      *
     75      * An application must hold the {@link android.Manifest.permission#BATTERY_STATS
     76      * android.permission.BATTERY_STATS} permission in order to retrieve any HealthStats
     77      * other than its own.
     78      *
     79      * @param uid User ID for a given application.
     80      * @return A {@link HealthStats} object containing the metrics for the requested
     81      * application. The keys for this HealthStats object will be from the {@link UidHealthStats}
     82      * class.
     83      * @see Process#myUid() Process.myUid()
     84      */
     85     public HealthStats takeUidSnapshot(int uid) {
     86         try {
     87             final HealthStatsParceler parceler = mBatteryStats.takeUidSnapshot(uid);
     88             return parceler.getHealthStats();
     89         } catch (RemoteException ex) {
     90             throw new RuntimeException(ex);
     91         }
     92     }
     93 
     94     /**
     95      * Return a {@link HealthStats} object containing a snapshot of system health
     96      * metrics for the application calling this API. This method is the same as calling
     97      * {@code takeUidSnapshot(Process.myUid())}.
     98      *
     99      * @return A {@link HealthStats} object containing the metrics for this application. The keys
    100      * for this HealthStats object will be from the {@link UidHealthStats} class.
    101      */
    102     public HealthStats takeMyUidSnapshot() {
    103         return takeUidSnapshot(Process.myUid());
    104     }
    105 
    106     /**
    107      * Return a {@link HealthStats} object containing a snapshot of system health
    108      * metrics for the given uids (user-id, which in usually corresponds to application).
    109      * @more
    110      *
    111      * An application must hold the {@link android.Manifest.permission#BATTERY_STATS
    112      * android.permission.BATTERY_STATS} permission in order to retrieve any HealthStats
    113      * other than its own.
    114      *
    115      * @param uids An array of User IDs to retrieve.
    116      * @return An array of {@link HealthStats} objects containing the metrics for each of
    117      * the requested uids. The keys for this HealthStats object will be from the
    118      * {@link UidHealthStats} class.
    119      */
    120     public HealthStats[] takeUidSnapshots(int[] uids) {
    121         try {
    122             final HealthStatsParceler[] parcelers = mBatteryStats.takeUidSnapshots(uids);
    123             final HealthStats[] results = new HealthStats[uids.length];
    124             final int N = uids.length;
    125             for (int i=0; i<N; i++) {
    126                 results[i] = parcelers[i].getHealthStats();
    127             }
    128             return results;
    129         } catch (RemoteException ex) {
    130             throw new RuntimeException(ex);
    131         }
    132     }
    133 
    134 }
    135 
    136