xref: /external/chromium_org/third_party/libaddressinput/src/java/src/com/android/i18n/addressinput/Util.java

/*
 * Copyright (C) 2010 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.i18n.addressinput;

import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Utility functions used by the address widget.
 */
class Util {
    /**
     * This variable is in upper-case, since we convert the language code to upper case before doing
     * string comparison.
     */
    private static final String LATIN_SCRIPT = "LATN";

    /**
     * Map of countries that have non-latin local names, with the language that their local names
     * are in. We only list a country here if we have the appropriate data. Only language sub-tags
     * are listed.
     */
     private static final Map<String, String> nonLatinLocalLanguageCountries =
             new HashMap<String, String>();
     static {
       nonLatinLocalLanguageCountries.put("AM", "hy");
       nonLatinLocalLanguageCountries.put("CN", "zh");
       nonLatinLocalLanguageCountries.put("HK", "zh");
       nonLatinLocalLanguageCountries.put("JP", "ja");
       nonLatinLocalLanguageCountries.put("KP", "ko");
       nonLatinLocalLanguageCountries.put("KR", "ko");
       nonLatinLocalLanguageCountries.put("MO", "zh");
       nonLatinLocalLanguageCountries.put("TH", "th");
       nonLatinLocalLanguageCountries.put("TW", "zh");
       nonLatinLocalLanguageCountries.put("VN", "vi");
     }

    /**
     * Cannot instantiate this class - private constructor.
     */
    private Util() {
    }

    /**
     * Returns true if the language code is explicitly marked to be in the latin script. For
     * example, "zh-Latn" would return true, but "zh-TW", "en" and "zh" would all return false.
     */
    static boolean isExplicitLatinScript(String languageCode) {
        // Convert to upper-case for easier comparison.
        languageCode = languageCode.toUpperCase();
        // Check to see if the language code contains a script modifier.
        final Pattern languageCodePattern = Pattern.compile("\\w{2,3}[-_](\\w{4})");
        Matcher m = languageCodePattern.matcher(languageCode);
        if (m.lookingAt()) {
            String script = m.group(1);
            if (script.equals(LATIN_SCRIPT)) {
                return true;
            }
        }
        return false;
    }

    /**
     * Returns the language subtag of a language code. For example, returns "zh" if given "zh-Hans",
     * "zh-CN" or other "zh" variants. If no language subtag can be found or the language tag is
     * malformed, returns "und".
     */
    static String getLanguageSubtag(String languageCode) {
        final Pattern languageCodePattern = Pattern
                .compile("(\\w{2,3})(?:[-_]\\w{4})?(?:[-_]\\w{2})?");
        Matcher m = languageCodePattern.matcher(languageCode);
        if (m.matches()) {
            return m.group(1).toLowerCase();
        }
        return "und";
    }

    /**
     * Trims the string. If the field is empty after trimming, returns null instead. Note that this
     * only trims ASCII white-space.
     */
    static String trimToNull(String originalStr) {
        if (originalStr == null) {
            return null;
        }
        String trimmedString = originalStr.trim();
        return (trimmedString.length() == 0) ? null : trimmedString;
    }

    /**
     * Throws an exception if the object is null, with a generic error message.
     */
    static void checkNotNull(Object o) throws NullPointerException {
        checkNotNull(o, "This object should not be null.");
    }

    /**
     * Throws an exception if the object is null, with the error message supplied.
     */
    static void checkNotNull(Object o, String message) throws NullPointerException {
        if (o == null) {
            throw new NullPointerException(message);
        }
    }

    /**
     * Joins input string with the given separator. If an input string is null, it will be skipped.
     */
    static String joinAndSkipNulls(String separator, String... strings) {
        StringBuilder sb = null;
        for (String s : strings) {
            if (s != null) {
                s = s.trim();
                if (s.length() > 0) {
                    if (sb == null) {
                        sb = new StringBuilder(s);
                    } else {
                        sb.append(separator).append(s);
                    }
                }
            }
        }
        return sb == null ? null : sb.toString();
    }

    /**
     * Builds a map of the lower-cased values of the keys, names and local names provided. Each name
     * and local name is mapped to its respective key in the map.
     *
     * @throws IllegalStateException if the names or lnames array is greater than the keys array.
     */
    static Map<String, String> buildNameToKeyMap(String[] keys, String[] names, String[] lnames) {
        if (keys == null) {
            return null;
        }

        Map<String, String> nameToKeyMap = new HashMap<String, String>();

        int keyLength = keys.length;
        for (String k : keys) {
            nameToKeyMap.put(k.toLowerCase(), k);
        }
        if (names != null) {
            if (names.length > keyLength) {
                throw new IllegalStateException(
                        "names length (" + names.length + ") is greater than keys length (" +
                        keys.length + ")");
            }
            for (int i = 0; i < keyLength; i++) {
                // If we have less names than keys, we ignore all missing names. This happens
                // generally because reg-ex splitting methods on different platforms (java, js etc)
                // behave differently in the default case. Since missing names are fine, we opt to
                // be more robust here.
                if (i < names.length && names[i].length() > 0) {
                    nameToKeyMap.put(names[i].toLowerCase(), keys[i]);
                }
            }
        }
        if (lnames != null) {
            if (lnames.length > keyLength) {
                throw new IllegalStateException(
                        "lnames length (" + lnames.length + ") is greater than keys length (" +
                        keys.length + ")");
            }
            for (int i = 0; i < keyLength; i++) {
                if (i < lnames.length && lnames[i].length() > 0) {
                    nameToKeyMap.put(lnames[i].toLowerCase(), keys[i]);
                }
            }
        }
        return nameToKeyMap;
    }

    /**
     * Returns a language code that the widget can use when fetching data, based on a {@link
     * java.util.Locale} language and the current selected country in the address widget. This
     * method is necessary since we have to determine later whether a language is "local" or "latin"
     * for certain countries.
     *
     * @param language the current user language
     * @param currentCountry the current selected country
     * @return a language code string in BCP-47 format (e.g. "en", "zh-Latn", "zh-Hans" or
     * "en-US").
     */
    static String getWidgetCompatibleLanguageCode(Locale language, String currentCountry) {
        String country = currentCountry.toUpperCase();
        // Only do something if the country is one of those where we have names in the local
        // language as well as in latin script.
        if (nonLatinLocalLanguageCountries.containsKey(country)) {
            String languageTag = language.getLanguage();
            // Only do something if the language tag is _not_ the local language.
            if (!languageTag.equals(nonLatinLocalLanguageCountries.get(country))) {
                // Build up the language tag with the country and language specified, and add in the
                // script-tag of "Latn" explicitly, since this is _not_ a local language. This means
                // that we might create a language tag of "th-Latn", which is not what the actual
                // language being used is, but it indicates that we prefer "Latn" names to whatever
                // the local alternative was.
                StringBuilder languageTagBuilder = new StringBuilder(languageTag);
                languageTagBuilder.append("_latn");
                if (language.getCountry().length() > 0) {
                    languageTagBuilder.append("_");
                    languageTagBuilder.append(language.getCountry());
                }
                return languageTagBuilder.toString();
            }
        }
        return language.toString();
    }
}