LocationProvider.java revision 54b6cfa9a9e5b861a9930af873580d6dc20f773c 
1/*
2 * Copyright (C) 2007 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.location;
18
19/**
20 * An abstract superclass for location providers.  A location provider
21 * provides periodic reports on the geographical location of the
22 * device.
23 *
24 * <p> Each provider has a set of criteria under which it may be used;
25 * for example, some providers require GPS hardware and visibility to
26 * a number of satellites; others require the use of the cellular
27 * radio, or access to a specific carrier's network, or to the
28 * internet.  They may also have different battery consumption
29 * characteristics or monetary costs to the user.  The {@link
30 * Criteria} class allows providers to be selected based on
31 * user-specified criteria.
32 */
33public abstract class LocationProvider {
34    private static final String TAG = "LocationProvider";
35    // A regular expression matching characters that may not appear
36    // in the name of a LocationProvider.
37    static final String BAD_CHARS_REGEX = "[^a-zA-Z0-9]";
38
39    private String mName;
40
41    public static final int OUT_OF_SERVICE = 0;
42    public static final int TEMPORARILY_UNAVAILABLE = 1;
43    public static final int AVAILABLE = 2;
44
45    /**
46     * Constructs a LocationProvider with the given name.   Provider names must
47     * consist only of the characters [a-zA-Z0-9].
48     *
49     * @throws IllegalArgumentException if name contains an illegal character
50     */
51    LocationProvider(String name) {
52        if (name.matches(BAD_CHARS_REGEX)) {
53            throw new IllegalArgumentException("name " + name +
54                " contains an illegal character");
55        }
56        // Log.d(TAG, "Constructor: name = " + name);
57        mName = name;
58    }
59
60    /**
61     * Returns the name of this provider.
62     */
63    public String getName() {
64        return mName;
65    }
66
67    /**
68     * Returns true if this provider meets the given criteria,
69     * false otherwise.
70     */
71    public boolean meetsCriteria(Criteria criteria) {
72        if ((criteria.getAccuracy() != Criteria.NO_REQUIREMENT) &&
73            (criteria.getAccuracy() < getAccuracy())) {
74            return false;
75        }
76        int criteriaPower = criteria.getPowerRequirement();
77        if ((criteriaPower != Criteria.NO_REQUIREMENT) &&
78            (criteriaPower < getPowerRequirement())) {
79            return false;
80        }
81        if (criteria.isAltitudeRequired() && !supportsAltitude()) {
82            return false;
83        }
84        if (criteria.isSpeedRequired() && !supportsSpeed()) {
85            return false;
86        }
87        if (criteria.isBearingRequired() && !supportsBearing()) {
88            return false;
89        }
90        return true;
91    }
92
93    /**
94     * Returns true if the provider requires access to a
95     * data network (e.g., the Internet), false otherwise.
96     */
97    public abstract boolean requiresNetwork();
98
99    /**
100     * Returns true if the provider requires access to a
101     * satellite-based positioning system (e.g., GPS), false
102     * otherwise.
103     */
104    public abstract boolean requiresSatellite();
105
106    /**
107     * Returns true if the provider requires access to an appropriate
108     * cellular network (e.g., to make use of cell tower IDs), false
109     * otherwise.
110     */
111    public abstract boolean requiresCell();
112
113    /**
114     * Returns true if the use of this provider may result in a
115     * monetary charge to the user, false if use is free.  It is up to
116     * each provider to give accurate information.
117     */
118    public abstract boolean hasMonetaryCost();
119
120    /**
121     * Returns true if the provider is able to provide altitude
122     * information, false otherwise.  A provider that reports altitude
123     * under most circumstances but may occassionally not report it
124     * should return true.
125     */
126    public abstract boolean supportsAltitude();
127
128    /**
129     * Returns true if the provider is able to provide speed
130     * information, false otherwise.  A provider that reports speed
131     * under most circumstances but may occassionally not report it
132     * should return true.
133     */
134    public abstract boolean supportsSpeed();
135
136    /**
137     * Returns true if the provider is able to provide bearing
138     * information, false otherwise.  A provider that reports bearing
139     * under most circumstances but may occassionally not report it
140     * should return true.
141     */
142    public abstract boolean supportsBearing();
143
144    /**
145     * Returns the power requirement for this provider.
146     *
147     * @return the power requirement for this provider, as one of the
148     * constants Criteria.POWER_REQUIREMENT_*.
149     */
150    public abstract int getPowerRequirement();
151
152    /**
153     * Returns a constant describing horizontal accuracy of this provider.
154     * If the provider returns finer grain or exact location,
155     * {@link Criteria#ACCURACY_FINE} is returned, otherwise if the
156     * location is only approximate then {@link Criteria#ACCURACY_COARSE}
157     * is returned.
158     */
159    public abstract int getAccuracy();
160}
161