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 
17 
18 package com.android.server.location;
19 
20 import android.app.PendingIntent;
21 import android.location.Geofence;
22 import android.location.Location;
23 
24 /**
25  * Represents state associated with a geofence
26  */
27 public class GeofenceState {
28     public final static int FLAG_ENTER = 0x01;
29     public final static int FLAG_EXIT = 0x02;
30 
31     private static final int STATE_UNKNOWN = 0;
32     private static final int STATE_INSIDE = 1;
33     private static final int STATE_OUTSIDE = 2;
34 
35     public final Geofence mFence;
36     private final Location mLocation;
37     public final long mExpireAt;
38     public final int mAllowedResolutionLevel;
39     public final int mUid;
40     public final String mPackageName;
41     public final PendingIntent mIntent;
42 
43     int mState;  // current state
44     double mDistanceToCenter;  // current distance to center of fence
45 
GeofenceState(Geofence fence, long expireAt, int allowedResolutionLevel, int uid, String packageName, PendingIntent intent)46     public GeofenceState(Geofence fence, long expireAt,
47             int allowedResolutionLevel, int uid, String packageName, PendingIntent intent) {
48         mState = STATE_UNKNOWN;
49         mDistanceToCenter = Double.MAX_VALUE;
50 
51         mFence = fence;
52         mExpireAt = expireAt;
53         mAllowedResolutionLevel = allowedResolutionLevel;
54         mUid = uid;
55         mPackageName = packageName;
56         mIntent = intent;
57 
58         mLocation = new Location("");
59         mLocation.setLatitude(fence.getLatitude());
60         mLocation.setLongitude(fence.getLongitude());
61     }
62 
63     /**
64      * Process a new location.
65      * @return FLAG_ENTER or FLAG_EXIT if the fence was crossed, 0 otherwise
66      */
processLocation(Location location)67     public int processLocation(Location location) {
68         mDistanceToCenter = mLocation.distanceTo(location);
69 
70         int prevState = mState;
71         //TODO: inside/outside detection could be made more rigorous
72         boolean inside = mDistanceToCenter <= Math.max(mFence.getRadius(), location.getAccuracy());
73         if (inside) {
74             mState = STATE_INSIDE;
75             if (prevState != STATE_INSIDE) {
76                 return FLAG_ENTER; // return enter if previously exited or unknown
77             }
78         } else {
79             mState = STATE_OUTSIDE;
80             if (prevState == STATE_INSIDE) {
81                 return FLAG_EXIT; // return exit only if previously entered
82             }
83         }
84         return 0;
85     }
86 
87     /**
88      * Gets the distance from the current location to the fence's boundary.
89      * @return The distance or {@link Double#MAX_VALUE} if unknown.
90      */
getDistanceToBoundary()91     public double getDistanceToBoundary() {
92         if (Double.compare(mDistanceToCenter, Double.MAX_VALUE) == 0) {
93             return Double.MAX_VALUE;
94         } else {
95             return Math.abs(mFence.getRadius() - mDistanceToCenter);
96         }
97     }
98 
99     @Override
toString()100     public String toString() {
101         String state;
102         switch (mState) {
103             case STATE_INSIDE:
104                 state = "IN";
105                 break;
106             case STATE_OUTSIDE:
107                 state = "OUT";
108                 break;
109             default:
110                 state = "?";
111         }
112         return String.format("%s d=%.0f %s", mFence.toString(), mDistanceToCenter, state);
113     }
114 }
115