Java tutorial
/* * Copyright 2008 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.google.gwt.i18n.client; import com.google.gwt.core.client.GWT; import com.google.gwt.i18n.client.constants.DateTimeConstants; import com.google.gwt.i18n.client.constants.NumberConstants; import com.google.gwt.i18n.client.impl.CldrImpl; import com.google.gwt.i18n.client.impl.LocaleInfoImpl; /** * Provides access to the currently-active locale and the list of available * locales. */ @SuppressWarnings("deprecation") public class LocaleInfo { /** * Currently we only support getting the currently running locale, so this * is a static. In the future, we would need a hash map from locale names * to LocaleInfo instances. */ private static LocaleInfo instance = new LocaleInfo((LocaleInfoImpl) GWT.create(LocaleInfoImpl.class), (CldrImpl) GWT.create(CldrImpl.class)); /** * Returns an array of available locale names. */ public static final String[] getAvailableLocaleNames() { /* * The set of all locales is constant across all permutations, so this * is static. Ideally, the set of available locales would be generated * by a different GWT.create but that would slow the compilation process * unnecessarily. * * This is static, and accesses infoImpl this way, with an eye towards * when we implement static LocaleInfo getLocale(String localeName) as * you might want to get the list of available locales in order to create * instances of each of them. */ return instance.infoImpl.getAvailableLocaleNames(); } /** * Returns a LocaleInfo instance for the current locale. */ public static final LocaleInfo getCurrentLocale() { /* * In the future, we could make additional static methods which returned a * LocaleInfo instance for a specific locale (from the set of those the app * was compiled with), accessed via a method like: * public static LocaleInfo getLocale(String localeName) */ return instance; } /** * Returns the name of the name of the cookie holding the locale to use, * which is defined in the config property {@code locale.cookie}. * * @return locale cookie name, or null if none */ public static final String getLocaleCookieName() { return instance.infoImpl.getLocaleCookieName(); } /** * Returns the display name of the requested locale in its native locale, if * possible. If no native localization is available, the English name will * be returned, or as a last resort just the locale name will be returned. If * the locale name is unknown (including an user overrides) or is not a valid * locale property value, null is returned. * * If the I18N module has not been imported, this will always return null. * * @param localeName the name of the locale to lookup. * @return the name of the locale in its native locale */ public static String getLocaleNativeDisplayName(String localeName) { /* * See the comment from getAvailableLocaleNames() above. */ return instance.infoImpl.getLocaleNativeDisplayName(localeName); } /** * Returns the name of the query parameter holding the locale to use, which is * defined in the config property {@code locale.queryparam}. * * @return locale URL query parameter name, or null if none */ public static String getLocaleQueryParam() { return instance.infoImpl.getLocaleQueryParam(); } /** * Returns true if any locale supported by this build of the app is RTL. */ public static boolean hasAnyRTL() { return instance.infoImpl.hasAnyRTL(); } private final LocaleInfoImpl infoImpl; private final CldrImpl cldrImpl; private DateTimeConstants dateTimeConstants; private DateTimeFormatInfo dateTimeFormatInfo; private NumberConstants numberConstants; /** * Constructor to be used by subclasses, such as mock classes for testing. * Any such subclass should override all methods. */ protected LocaleInfo() { infoImpl = null; cldrImpl = null; } /** * Create a LocaleInfo instance, passing in the implementation classes. * * @param impl LocaleInfoImpl instance to use * @param cldr CldrImpl instance to use */ private LocaleInfo(LocaleInfoImpl impl, CldrImpl cldr) { this.infoImpl = impl; this.cldrImpl = cldr; } /** * Returns a DateTimeConstants instance for this locale. */ public final DateTimeConstants getDateTimeConstants() { ensureDateTimeConstants(); return dateTimeConstants; } /** * Returns a DateTimeConstants instance for this locale. */ public final DateTimeFormatInfo getDateTimeFormatInfo() { ensureDateTimeFormatInfo(); return dateTimeFormatInfo; } /** * Returns the name of this locale, such as "default, "en_US", etc. */ public final String getLocaleName() { return infoImpl.getLocaleName(); } /** * @return an implementation of {@link LocalizedNames} for this locale. */ public final LocalizedNames getLocalizedNames() { return infoImpl.getLocalizedNames(); } /** * Returns a NumberConstants instance for this locale. */ public final NumberConstants getNumberConstants() { ensureNumberConstants(); return numberConstants; } /** * Returns true if this locale is right-to-left instead of left-to-right. */ public final boolean isRTL() { return cldrImpl.isRTL(); } private void ensureDateTimeConstants() { if (dateTimeConstants == null) { ensureDateTimeFormatInfo(); dateTimeConstants = new DateTimeConstantsAdapter(dateTimeFormatInfo); } } private void ensureDateTimeFormatInfo() { if (dateTimeFormatInfo == null) { dateTimeFormatInfo = infoImpl.getDateTimeFormatInfo(); } } private void ensureNumberConstants() { if (numberConstants == null) { numberConstants = infoImpl.getNumberConstants(); } } }