Java tutorial
// Copyright (c) 2013 The Chromium Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. package com.google.cordova; import java.io.BufferedReader; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Locale; import java.util.Map; import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; import org.apache.cordova.CordovaArgs; import org.apache.cordova.CordovaWebView; import org.apache.cordova.JSONUtils; import org.apache.cordova.api.CallbackContext; import org.apache.cordova.api.CordovaInterface; import org.apache.cordova.api.CordovaPlugin; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import android.annotation.SuppressLint; import android.content.Context; import android.content.res.AssetManager; import android.text.TextUtils; import android.util.Log; import android.view.View; public class ChromeI18n extends CordovaPlugin implements ChromeExtensionURLs.RequestModifyInterface { private static final String LOG_TAG = "ChromeI18n"; // Ensure we register with Chrome Extension Urls just once private static ChromeI18n registeredInstance = null; // Choose a priority for org.apache.cordova.ChromeExtensionURLs. This should be unique for any plugin that wants to register private final int CHROME_EXTENSION_URL_PRIORITY = 1000; // Save the locale chain so we don't have to recalculate each time private List<String> chosenLocales; // Save any retrieved message.json contents in memory so that we don't have to retrieve it again private Map<String, JSONObject> memoizedJsonContents = new HashMap<String, JSONObject>(); // The pattern of any messages we need to replace private Pattern patterRegex = Pattern.compile("__MSG_(@@)?[a-zA-Z0-9_-]*__"); public void initialize(CordovaInterface cordova, CordovaWebView webView) { super.initialize(cordova, webView); // Unregister any old ChromeI18n objects. This should not be required as Cordova maintains a single instance of each plugin if (registeredInstance != null) { if (ChromeExtensionURLs.unregisterInterfaceAtPriority(registeredInstance, CHROME_EXTENSION_URL_PRIORITY)) { registeredInstance = null; } else { throw new IllegalArgumentException("Unable to unregister the existing interface at priority : " + CHROME_EXTENSION_URL_PRIORITY + ". Possible duplication of priority by multiple plugins"); } } if (ChromeExtensionURLs.registerInterfaceAtPriority(this, CHROME_EXTENSION_URL_PRIORITY)) { registeredInstance = this; } else { throw new IllegalArgumentException("Unable to register the interface at priority : " + CHROME_EXTENSION_URL_PRIORITY + ". Possible duplication of priority by multiple plugins"); } } @Override public boolean execute(String action, CordovaArgs args, final CallbackContext callbackContext) throws JSONException { if ("getAcceptLanguages".equals(action)) { getAcceptLanguages(args, callbackContext); return true; } return false; } private void getAcceptLanguages(final CordovaArgs args, final CallbackContext callbackContext) { try { JSONArray ret = new JSONArray(); Locale locale = Locale.getDefault(); String localString = locale.toString().replace('_', '-'); ret.put(localString); callbackContext.success(ret); } catch (Exception e) { callbackContext.error("Could not retrieve supported locales"); Log.e(LOG_TAG, "Could not retrieve supported locales", e); } } @Override public String modifyNewRequestUrl(String url) { return replacePatternsInLine(url); } @Override public InputStream modifyResponseInputStream(String url, InputStream is) { String cleanUrl = url.split("\\?")[0].split("#")[0]; String[] urlParts = cleanUrl.split("/"); String fileName = urlParts[urlParts.length - 1]; try { if (fileName.endsWith(".css") || fileName.equals("manifest.json")) { is = replaceI18nPlaceholders(is); } } catch (IOException ioe) { Log.e(LOG_TAG, "Error occurred while replacing i18n Tags in file: " + fileName, ioe); // If an error occurs, unlocalized content is returned } return is; } private InputStream replaceI18nPlaceholders(InputStream is) throws IOException { // Process the input stream line by line // Default byte array size is 32 bytes. Use something more reasonable for web resources - 32K int defaultByteArraySize = 32768; String ls = System.getProperty("line.separator"); ByteArrayOutputStream os = new ByteArrayOutputStream(defaultByteArraySize); String line = null; BufferedReader reader = new BufferedReader(new InputStreamReader(is)); while ((line = reader.readLine()) != null) { line = replacePatternsInLine(line); // Note the last line might get an extra \n pushed in. This shouldn't affect the loading of web resources os.write((line + ls).getBytes()); } return new ByteArrayInputStream(os.toByteArray()); } private String replacePatternsInLine(String line) { try { Matcher matcher = patterRegex.matcher(line); StringBuilder constructedLine = new StringBuilder(); int currStart = 0; while (currStart < line.length() && matcher.find(currStart)) { String preString = line.substring(currStart, matcher.start()); String match = matcher.group(); constructedLine.append(preString); constructedLine.append(getReplacement(match)); currStart = matcher.end(); } //get the remaining piece constructedLine.append(line.substring(currStart)); return constructedLine.toString(); } catch (Exception e) { Log.e(LOG_TAG, "An error occurred during the i18n of line : " + line, e); // Return the line itself as it is a more graceful fallback than return nothing return line; } } @SuppressLint("NewApi") private static boolean isRtlLocale(Locale l) { if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.JELLY_BEAN_MR1) { return View.LAYOUT_DIRECTION_RTL == TextUtils.getLayoutDirectionFromLocale(l); } String lang = l.getLanguage().toLowerCase(Locale.ENGLISH); return (lang.equals("ar") || lang.equals("fa") || lang.equals("ur") || lang.equals("ps") || lang.equals("syr") || lang.equals("dv") || lang.equals("he") || lang.equals("yi")); } private String getReplacement(String match) { // get the message from __MSG_messagename__ String messageName = match.substring(6, match.length() - 2).toLowerCase(Locale.ENGLISH); if (messageName.startsWith("@@")) { Locale locale = Locale.getDefault(); if ("@@extension_id".equals(messageName)) { return "{appId}"; } else if ("@@ui_locale".equals(messageName)) { return locale.toString(); } else if ("@@bidi_dir".equals(messageName)) { return isRtlLocale(locale) ? "rtl" : "ltr"; } else if ("@@bidi_reversed_dir".equals(messageName)) { return isRtlLocale(locale) ? "ltr" : "rtl"; } else if ("@@bidi_start_edge".equals(messageName)) { return isRtlLocale(locale) ? "right" : "left"; } else if ("@@bidi_end_edge".equals(messageName)) { return isRtlLocale(locale) ? "left" : "right"; } } // Look for replacement in messages.json files List<String> localeChain = getLocalesToUse(); JSONObject messageObject = getMessageFromMessageJson(messageName, localeChain); if (messageObject != null) { String ret = messageObject.optString("message"); if (ret != null) { return ret; } } // Didn't find a match, just return string as is return match; } private List<String> getLocalesToUse() { try { if (chosenLocales == null) { List<String> localesToUse = new ArrayList<String>(); String windowLocale = Locale.getDefault().toString().toLowerCase().replace('-', '_'); localesToUse.add(windowLocale); // Construct fallback chain int lastIndex; while ((lastIndex = windowLocale.lastIndexOf('_')) != -1) { windowLocale = windowLocale.substring(0, lastIndex); localesToUse.add(windowLocale); } String defaultLocale = getDefaultLocale(); if (!localesToUse.contains(defaultLocale)) { localesToUse.add(defaultLocale); } chosenLocales = new ArrayList<String>(); for (int i = 0; i < localesToUse.size(); i++) { String currentLocale = localesToUse.get(i); if (isLocaleAvailable(currentLocale)) { chosenLocales.add(currentLocale); } } } } catch (Exception e) { Log.e(LOG_TAG, "Error occurred while retrieving usable locales", e); } return chosenLocales; } private JSONObject getMessageFromMessageJson(String messageName, List<String> localeChain) { try { for (int i = 0; i < localeChain.size(); i++) { String locale = localeChain.get(i); if (memoizedJsonContents.get(locale) == null) { String fileName = "www/locales/" + locale + "/messages.json"; JSONObject contents = getAssetContents(fileName); // convert all fields to lower case to check case insensitively contents = toLowerCaseMessage(contents); memoizedJsonContents.put(locale, contents); } JSONObject ret = memoizedJsonContents.get(locale).optJSONObject(messageName); if (ret != null) { return ret; } } } catch (Exception e) { Log.e(LOG_TAG, "Error occurred while reading through the messages.json files", e); } return null; } private JSONObject toLowerCaseMessage(JSONObject contents) throws JSONException { List<String> messages = JSONUtils.toStringList(contents.names()); for (String message : messages) { JSONObject value = contents.getJSONObject(message); contents.remove(message); contents.put(message.toLowerCase(), value); } return contents; } private boolean isLocaleAvailable(String locale) throws IOException { List<String> availableLocales = new ArrayList<String>(); AssetManager am = this.cordova.getActivity().getAssets(); String[] localesArr = am.list("www/locales"); for (String currLocale : localesArr) { try { // Check that the manifest.json exists InputStream is = am.open("www/locales/" + currLocale + "/messages.json"); is.close(); availableLocales.add(currLocale); } catch (IOException e) { /* Suppress not found exceptions */ } } return availableLocales.contains(locale); } private String getDefaultLocale() throws JSONException, IOException { JSONObject manifestContents = getAssetContents("www/manifest.json"); String defaultLocale = manifestContents.optString("default_locale"); if (defaultLocale == null) { throw new IllegalArgumentException("Default Locale not defined"); } return defaultLocale; } private JSONObject getAssetContents(String assetName) throws IOException, JSONException { Context context = this.cordova.getActivity(); InputStream is = context.getAssets().open(assetName); //Small trick to get the scanner to pull the entire input stream in one go Scanner s = new java.util.Scanner(is).useDelimiter("\\A"); String contents = s.hasNext() ? s.next() : ""; return new JSONObject(contents); } }