LocationStatsAggregator.java revision 5d42ffa9462f87edbbdc61a8719f6c521c700de5 
1/*
2 * Copyright (C) 2012 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 android.bordeaux.services;
18
19import android.content.Context;
20import android.location.Criteria;
21import android.location.Location;
22import android.location.LocationListener;
23import android.location.LocationManager;
24import android.location.LocationProvider;
25import android.os.Bundle;
26import android.os.Handler;
27import android.os.HandlerThread;
28import android.os.Message;
29import android.os.Process;
30import android.util.Log;
31import java.util.HashMap;
32import java.util.Map;
33
34// TODO: add functionality to detect speed (use GPS) when needed
35// withouth draining the battery quickly
36public class LocationStatsAggregator extends Aggregator {
37    final String TAG = "LocationStatsAggregator";
38    public static final String CURRENT_LOCATION = "Current Location";
39    public static final String CURRENT_SPEED = "Current Speed";
40
41    // TODO: Collect location on every minute
42    private static final long MINIMUM_TIME = 60000; // milliseconds
43
44    // reset best location provider on every 5 minutes
45    private static final int BEST_PROVIDER_DURATION = 300000;
46
47    private static final float MINIMUM_DISTANCE = 0f; // meter
48
49    private static final int LOCATION_CHANGE = 1;
50
51    // record time when the location provider is set
52    private long mProviderSetTime;
53
54    private Handler mHandler;
55    private HandlerThread mHandlerThread;
56    private LocationManager mLocationManager;
57    private ClusterManager mClusterManager;
58
59    public LocationStatsAggregator(final Context context) {
60        mLocationManager =
61            (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);
62        setClusteringThread(context);
63        requestLocationUpdate();
64    }
65
66    public String[] getListOfFeatures(){
67        String[] list = { CURRENT_LOCATION } ;
68        return list;
69    }
70
71    public Map<String,String> getFeatureValue(String featureName) {
72        HashMap<String,String> feature = new HashMap<String,String>();
73
74        if (featureName.equals(CURRENT_LOCATION)) {
75
76          // TODO: check last known location first before sending out location request.
77          /*
78            Location location =
79                mLocationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
80          */
81
82          // TODO: instead of outputing "unknow" should just not output anything.
83          feature.put(CURRENT_LOCATION, mClusterManager.getSemanticLocation());
84        }
85        return (Map) feature;
86    }
87
88    private void setClusteringThread(Context context) {
89        mClusterManager = new ClusterManager(context);
90
91        mHandlerThread = new HandlerThread("Location Handler",
92                Process.THREAD_PRIORITY_BACKGROUND);
93        mHandlerThread.start();
94        mHandler = new Handler(mHandlerThread.getLooper()) {
95
96            @Override
97            public void handleMessage(Message msg) {
98                if (!(msg.obj instanceof Location)) {
99                    return;
100                }
101                Location location = (Location) msg.obj;
102                switch(msg.what) {
103                    case LOCATION_CHANGE:
104                        mClusterManager.addSample(location);
105                        break;
106                    default:
107                        super.handleMessage(msg);
108                }
109            }
110        };
111    }
112
113    private void requestLocationUpdate() {
114        Criteria criteria = new Criteria();
115        criteria.setAccuracy(Criteria.ACCURACY_COARSE);
116        criteria.setPowerRequirement(Criteria.POWER_LOW);
117        /*
118        criteria.setAltitudeRequired(false);
119        criteria.setBearingRequired(false);
120        criteria.setSpeedRequired(true);
121        */
122        criteria.setCostAllowed(true);
123
124        String bestProvider = mLocationManager.getBestProvider(criteria, false);
125        Log.i(TAG, "Best Location Provider: " + bestProvider);
126
127        String bestAvailableProvider = mLocationManager.getBestProvider(criteria, true);
128        Log.i(TAG, "Best Available Location Provider: " + bestAvailableProvider);
129
130        mProviderSetTime = System.currentTimeMillis();
131        if (bestAvailableProvider != null) {
132            mLocationManager.requestLocationUpdates(
133                bestAvailableProvider, MINIMUM_TIME, MINIMUM_DISTANCE, mLocationListener);
134        }
135    }
136
137    private final LocationListener mLocationListener = new LocationListener() {
138        public void onLocationChanged(Location location) {
139            long currentTime = location.getTime();
140            if (currentTime - mProviderSetTime < MINIMUM_TIME) {
141                return;
142            }
143            mHandler.sendMessage(mHandler.obtainMessage(LOCATION_CHANGE, location));
144            // search again for the location service
145            if (currentTime - mProviderSetTime > BEST_PROVIDER_DURATION) {
146                mLocationManager.removeUpdates(this);
147                Log.e(TAG, "reselect best location provider");
148                requestLocationUpdate();
149            }
150        }
151
152        public void onStatusChanged(String provider, int status, Bundle extras) { }
153
154        public void onProviderEnabled(String provider) { }
155
156        public void onProviderDisabled(String provider) { }
157    };
158}
159