Java tutorial
/** * Copyright (c) 2012-2013 Edgar Espina * * This file is part of Handlebars.java. * * 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.github.jknack.handlebars.helper; import static org.apache.commons.lang3.StringUtils.defaultIfEmpty; import static org.apache.commons.lang3.Validate.isTrue; import static org.apache.commons.lang3.Validate.notEmpty; import static org.apache.commons.lang3.Validate.notNull; import java.io.IOException; import java.text.MessageFormat; import java.util.ArrayList; import java.util.Enumeration; import java.util.List; import java.util.Locale; import java.util.ResourceBundle; import java.util.regex.Matcher; import java.util.regex.Pattern; import org.apache.commons.lang3.LocaleUtils; import com.github.jknack.handlebars.Handlebars; import com.github.jknack.handlebars.Helper; import com.github.jknack.handlebars.Options; /** * Implementation of i18n helper for Java and JavaScript. * <p> * The Java implementation use {@link ResourceBundle}. * </p> * <p> * The JavaScript version use the <a href="https://github.com/fnando/i18n-js">I18n</a> library. * {@link ResourceBundle} are converted to JavaScript code. * </p> * * @author edgar.espina * @since 0.9.0 * @see ResourceBundle */ public enum I18nHelper implements Helper<String> { /** * <p> * A helper built on top of {@link ResourceBundle}. A {@link ResourceBundle} is the most well * known mechanism for internationalization (i18n). * </p> * <p> * <h3>messages.properties:</h3> * </p> * * <pre> * hello=Hola * </pre> * * <h3>Basic Usage:</h3> * * <pre> * {{i18n "hello"}} * </pre> * * <p> * Will result in: <code>Hola</code> * </p> * <h3>Using a locale:</h3> * * <pre> * {{i18n "hello" locale="es_AR"}} * </pre> * * <h3>Using a different bundle:</h3> * * <pre> * {{i18n "hello" bundle="myMessages"}} * </pre> * * <h3>Using a message format:</h3> * * <pre> * hello=Hola {0}! * </pre> * * <pre> * {{i18n "hello" "Handlebars.java"}} * </pre> * * @author edgar.espina * @since 0.9.0 * @see ResourceBundle */ i18n { /** * <p> * A helper built on top of {@link ResourceBundle}. A {@link ResourceBundle} is the most well * known mechanism for internationalization (i18n). * </p> * <p> * <h3>messages.properties:</h3> * </p> * * <pre> * hello=Hola * </pre> * * <h3>Basic Usage:</h3> * * <pre> * {{i18n "hello"}} * </pre> * * <p> * Will result in: <code>Hola</code> * </p> * <h3>Using a locale:</h3> * * <pre> * {{i18n "hello" locale="es_AR"}} * </pre> * * <h3>Using a different bundle:</h3> * * <pre> * {{i18n "hello" bundle="myMessages"}} * </pre> * * <h3>Using a message format</h3> * * <pre> * hello=Hola {0}! * </pre> * * <pre> * {{i18n "hello" "Handlebars.java"}} * </pre> * * @param key The bundle's key. Required. * @param options The helper's options. Not null. * @return An i18n message. * @throws IOException If the bundle wasn't resolve. */ @Override public CharSequence apply(final String key, final Options options) throws IOException { notEmpty(key, "found: '%s', expected 'bundle's key'", key); Locale locale = LocaleUtils.toLocale((String) options.hash("locale", defaultLocale.toString())); String baseName = options.hash("bundle", defaultBundle); ClassLoader classLoader = options.hash("classLoader", getClass().getClassLoader()); I18nSource localSource = source == null ? new DefI18nSource(baseName, locale, classLoader) : source; return localSource.message(key, locale, options.params); } }, /** * <p> * Translate a {@link ResourceBundle} into JavaScript code. The generated code assume you added * the <a href="https://github.com/fnando/i18n-js">I18n</a> * </p> * <p> * It converts message patterns like: <code>Hi {0}</code> into <code>Hi {{arg0}}</code>. This make * possible to the I18n JS library to interpolate variables. * </p> * <p> * Note: make sure you include <a href="https://github.com/fnando/i18n-js">I18n</a> in your * application. Otherwise, the generated code will fail. * </p> * <p> * Usage: * </p> * * <pre> * {{i18nJs locale?}} * </pre> * * If locale argument is present it will translate that locale to JavaScript. Otherwise, the * default locale. */ i18nJs { /** * The message format pattern. */ private final Pattern pattern = Pattern.compile("\\{(\\d+)\\}"); /** * <p> * Translate a {@link ResourceBundle} into JavaScript code. The generated code assume you added * the <a href="https://github.com/fnando/i18n-js">I18n</a> * </p> * <p> * It converts message patterns like: <code>Hi {0}</code> into <code>Hi {{arg0}}</code>. This * make possible to the I18n JS library to interpolate variables. * </p> * <p> * Note: make sure you include <a href="https://github.com/fnando/i18n-js">I18n</a> in your * application. Otherwise, the generated code will fail. * </p> * <p> * Usage: * </p> * * <pre> * {{i18nJs [locale] [bundle=messages] [wrap=true]}} * </pre> * * If locale argument is present it will translate that locale to JavaScript. Otherwise, the * default locale. * * Use wrap=true for wrapping the code with a script tag. * * @param localeName The locale's name. Optional. * @param options The helper's options. Not null. * @return JavaScript code from {@link ResourceBundle}. * @throws IOException If bundle wasn't resolve. */ @Override public CharSequence apply(final String localeName, final Options options) throws IOException { Locale locale = LocaleUtils.toLocale(defaultIfEmpty(localeName, defaultLocale.toString())); String baseName = options.hash("bundle", defaultBundle); ClassLoader classLoader = options.hash("classLoader", getClass().getClassLoader()); I18nSource localSource = source == null ? new DefI18nSource(baseName, locale, classLoader) : source; StringBuilder buffer = new StringBuilder(); Boolean wrap = options.hash("wrap", true); if (wrap) { buffer.append("<script type='text/javascript'>\n"); } buffer.append(" /* ").append(locale.getDisplayName()).append(" */\n"); buffer.append(" I18n.translations = I18n.translations || {};\n"); buffer.append(" I18n.translations['").append(locale.toString()).append("'] = {\n"); StringBuilder body = new StringBuilder(); String separator = ",\n"; String[] keys = localSource.keys(baseName, locale); for (String key : keys) { String message = message(localSource.message(key, locale)); body.append(" \"").append(key).append("\": "); body.append("\"").append(message).append("\"").append(separator); } if (body.length() > 0) { body.setLength(body.length() - separator.length()); buffer.append(body); } buffer.append("\n };\n"); if (wrap) { buffer.append("</script>\n"); } return new Handlebars.SafeString(buffer); } /** * Convert expression <code>{0}</code> into <code>{{arg0}}</code> and escape EcmaScript * characters. * * @param message The candidate message. * @return A valid I18n message. */ private String message(final String message) { String escapedMessage = Handlebars.Utils.escapeExpression(message); Matcher matcher = pattern.matcher(escapedMessage); StringBuffer result = new StringBuffer(); while (matcher.find()) { matcher.appendReplacement(result, "{{arg" + matcher.group(1) + "}}"); } matcher.appendTail(result); return result.toString(); } }; /** * The default locale. Required. */ protected Locale defaultLocale = Locale.getDefault(); /** * The default's bundle. Required. */ protected String defaultBundle = "messages"; /** The message source to use. */ protected I18nSource source; /** * Set the message source. * * @param source The message source. Required. * @NotThreadSafe Make sure to call this method ONCE at start time. */ public void setSource(final I18nSource source) { this.source = notNull(source, "The i18n source is required."); } /** * Set the default bundle's name. Default is: messages and this method let you override the * default bundle's name to something else. * * @param bundle The default's bundle name. Required. * @NotThreadSafe Make sure to call this method ONCE at start time. */ public void setDefaultBundle(final String bundle) { this.defaultBundle = notEmpty(bundle, "A bundle's name is required."); } /** * Set the default locale. Default is system dependent and this method let you override the * default bundle's name to something else. * * @param locale The default locale name. Required. * @NotThreadSafe Make sure to call this method ONCE at start time. */ public void setDefaultLocale(final Locale locale) { this.defaultLocale = notNull(locale, "A locale is required."); } } /** Default implementation of I18nSource. */ class DefI18nSource implements I18nSource { /** The resource bundle. */ private ResourceBundle bundle; /** * Creates a new {@link DefI18nSource}. * * @param baseName The base name. * @param locale The locale. * @param classLoader The classloader. */ public DefI18nSource(final String baseName, final Locale locale, final ClassLoader classLoader) { bundle = ResourceBundle.getBundle(baseName, locale, classLoader); } @Override public String[] keys(final String basename, final Locale locale) { Enumeration<String> keys = bundle.getKeys(); List<String> result = new ArrayList<String>(); while (keys.hasMoreElements()) { String key = keys.nextElement(); result.add(key); } return result.toArray(new String[result.size()]); } @Override public String message(final String key, final Locale locale, final Object... args) { isTrue(bundle.containsKey(key), "no message found: '%s' for locale '%s'.", key, locale); String message = bundle.getString(key); if (args.length == 0) { return message; } MessageFormat format = new MessageFormat(message, locale); return format.format(args); } };