1/*
2 * Copyright (C) 2010 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 libcore.icu;
18
19import java.util.ArrayList;
20import java.util.Arrays;
21import java.util.Comparator;
22import java.util.HashMap;
23import java.util.Locale;
24import java.util.TimeZone;
25import java.util.concurrent.TimeUnit;
26import libcore.util.BasicLruCache;
27import libcore.util.ZoneInfoDB;
28
29/**
30 * Provides access to ICU's time zone name data.
31 */
32public final class TimeZoneNames {
33    private static final String[] availableTimeZoneIds = TimeZone.getAvailableIDs();
34
35    /*
36     * Offsets into the arrays returned by DateFormatSymbols.getZoneStrings.
37     */
38    public static final int OLSON_NAME = 0;
39    public static final int LONG_NAME = 1;
40    public static final int SHORT_NAME = 2;
41    public static final int LONG_NAME_DST = 3;
42    public static final int SHORT_NAME_DST = 4;
43    public static final int NAME_COUNT = 5;
44
45    private static final ZoneStringsCache cachedZoneStrings = new ZoneStringsCache();
46    static {
47        // Ensure that we pull in the zone strings for the root locale, en_US, and the
48        // user's default locale. (All devices must support the root locale and en_US,
49        // and they're used for various system things like HTTP headers.) Pre-populating
50        // the cache is especially useful on Android because we'll share this via the Zygote.
51        cachedZoneStrings.get(Locale.ROOT);
52        cachedZoneStrings.get(Locale.US);
53        cachedZoneStrings.get(Locale.getDefault());
54    }
55
56    public static class ZoneStringsCache extends BasicLruCache<Locale, String[][]> {
57        public ZoneStringsCache() {
58            super(5); // Room for a handful of locales.
59        }
60
61        @Override protected String[][] create(Locale locale) {
62            long start = System.nanoTime();
63
64            // Set up the 2D array used to hold the names. The first column contains the Olson ids.
65            String[][] result = new String[availableTimeZoneIds.length][5];
66            for (int i = 0; i < availableTimeZoneIds.length; ++i) {
67                result[i][0] = availableTimeZoneIds[i];
68            }
69
70            long nativeStart = System.nanoTime();
71            fillZoneStrings(locale.toString(), result);
72            long nativeEnd = System.nanoTime();
73
74            internStrings(result);
75            // Ending up in this method too often is an easy way to make your app slow, so we ensure
76            // it's easy to tell from the log (a) what we were doing, (b) how long it took, and
77            // (c) that it's all ICU's fault.
78            long end = System.nanoTime();
79            long nativeDuration = TimeUnit.NANOSECONDS.toMillis(nativeEnd - nativeStart);
80            long duration = TimeUnit.NANOSECONDS.toMillis(end - start);
81            System.logI("Loaded time zone names for \"" + locale + "\" in " + duration + "ms" +
82                        " (" + nativeDuration + "ms in ICU)");
83            return result;
84        }
85
86        // De-duplicate the strings (http://b/2672057).
87        private synchronized void internStrings(String[][] result) {
88            HashMap<String, String> internTable = new HashMap<String, String>();
89            for (int i = 0; i < result.length; ++i) {
90                for (int j = 1; j < NAME_COUNT; ++j) {
91                    String original = result[i][j];
92                    String nonDuplicate = internTable.get(original);
93                    if (nonDuplicate == null) {
94                        internTable.put(original, original);
95                    } else {
96                        result[i][j] = nonDuplicate;
97                    }
98                }
99            }
100        }
101    }
102
103    private static final Comparator<String[]> ZONE_STRINGS_COMPARATOR = new Comparator<String[]>() {
104        public int compare(String[] lhs, String[] rhs) {
105            return lhs[OLSON_NAME].compareTo(rhs[OLSON_NAME]);
106        }
107    };
108
109    private TimeZoneNames() {}
110
111    /**
112     * Returns the appropriate string from 'zoneStrings'. Used with getZoneStrings.
113     */
114    public static String getDisplayName(String[][] zoneStrings, String id, boolean daylight, int style) {
115        String[] needle = new String[] { id };
116        int index = Arrays.binarySearch(zoneStrings, needle, ZONE_STRINGS_COMPARATOR);
117        if (index >= 0) {
118            String[] row = zoneStrings[index];
119            if (daylight) {
120                return (style == TimeZone.LONG) ? row[LONG_NAME_DST] : row[SHORT_NAME_DST];
121            } else {
122                return (style == TimeZone.LONG) ? row[LONG_NAME] : row[SHORT_NAME];
123            }
124        }
125        return null;
126    }
127
128    /**
129     * Returns an array of time zone strings, as used by DateFormatSymbols.getZoneStrings.
130     */
131    public static String[][] getZoneStrings(Locale locale) {
132        if (locale == null) {
133            locale = Locale.getDefault();
134        }
135        return cachedZoneStrings.get(locale);
136    }
137
138    /**
139     * Returns an array containing the time zone ids in use in the country corresponding to
140     * the given locale. This is not necessary for Java API, but is used by telephony as a
141     * fallback. We retrieve these strings from zone.tab rather than icu4c because the latter
142     * supplies them in alphabetical order where zone.tab has them in a kind of "importance"
143     * order (as defined in the zone.tab header).
144     */
145    public static String[] forLocale(Locale locale) {
146        String countryCode = locale.getCountry();
147        ArrayList<String> ids = new ArrayList<String>();
148        for (String line : ZoneInfoDB.getInstance().getZoneTab().split("\n")) {
149            if (line.startsWith(countryCode)) {
150                int olsonIdStart = line.indexOf('\t', 4) + 1;
151                int olsonIdEnd = line.indexOf('\t', olsonIdStart);
152                if (olsonIdEnd == -1) {
153                    olsonIdEnd = line.length(); // Not all zone.tab lines have a comment.
154                }
155                ids.add(line.substring(olsonIdStart, olsonIdEnd));
156            }
157        }
158        return ids.toArray(new String[ids.size()]);
159    }
160
161    public static native String getExemplarLocation(String locale, String tz);
162
163    private static native void fillZoneStrings(String locale, String[][] result);
164}
165