Translation.java

/*
 * This file is part of the aidGer project.
 *
 * Copyright (C) 2010-2013 The aidGer Team
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package de.aidger.utils;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Enumeration;
import java.util.List;
import java.util.Locale;
import java.util.PropertyResourceBundle;
import java.util.ArrayList;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

import de.aidger.model.Runtime;

/**
 * Sets the translation of the program. If Strings of the current language can't
 * be found, it will fall back to the default language.
 * 
 * @author aidGer Team
 */
public class Translation {

    /**
     * The file name of the translation.
     */
    protected String filePath;

    /**
     * The bundle holding the translation.
     */
    protected static PropertyResourceBundle bundle = null;

    /**
     * Initializes this class. Resolves the file path of the translation files.
     *
     * @param language
     *            The language to which the program will be translated.
     */
    public Translation(String language) {
        /* Create path if necessary */
        filePath = Runtime.getInstance().getConfigPath() + "lang/";

        File languagePath = new File(filePath);
        if ((!languagePath.exists() || !languagePath.isDirectory())
                && !languagePath.mkdirs()) {
            Logger.error("Couldn't create directory for translations.");
        }

        /* Load the language file */
        InputStream inputStream = null;

        if (!language.isEmpty() && !language.equals("en")) {
            /* Check first in .jar */
            String jarfile = Runtime.getInstance().getJarLocation();
            if (jarfile.endsWith(".jar")) {
                inputStream = getClass().getResourceAsStream(
                    "/de/aidger/res/lang/" + language + ".properties");
            }

            /* After that check in filesystem */
            if (inputStream == null) {
                try {
                    File inputFile = new File(filePath + language + ".properties");
                    inputStream = new FileInputStream(inputFile);
                } catch (Exception e) {
                    Logger
                        .info("Loading the translation from the filesystem failed. Only english will be available");
                }
            }

            /* Finally load the resource */
            if (inputStream != null) {
                try {
                    bundle = new PropertyResourceBundle(inputStream);
                    inputStream.close();
                } catch (IOException ex) {
                }
            }

            /* Instanciate the selected locale and set it as the default for the jvm */
            Locale def = new Locale(language);
            Locale.setDefault(def);
        } else if (language.isEmpty()) {
            Runtime.getInstance().setOption("language", "en");
        }
    }

    /**
     * Returns the translation of the specified string from the bundle.
     * 
     * @param id
     *            The string to translate.
     * @return The translated string or return the id.
     */
    public static String _(String id) {
        try {
            return bundle.getString(id);
        } catch (Exception e) {
            /*
             * If the string is not translated in the bundle, or the bundle
             * cannot be found, just return the original string.
             */
            return id;
        }
    }

    /**
     * Get a list of all languages installed on the system. The format is 0 =>
     * short, 1 => long language name.
     * 
     * @return The list of all installed languages
     */
    public static List<Pair<String, String>> getLanguages() {
        List<Pair<String, String>> list = new ArrayList<Pair<String, String>>();

        /* Add English as standard language */
        list.add(new Pair<String, String>("en", new Locale("en")
            .getDisplayLanguage()));

        /* Search all translations in the jar file */
        try {
            JarFile jf = new JarFile(Runtime.getInstance().getJarLocation());
            Enumeration ress = jf.entries();

            while (ress.hasMoreElements()) {
                JarEntry je = (JarEntry) ress.nextElement();

                if (je.getName().matches("de/aidger/res/lang/[a-z]+.properties")) {
                    int idx = je.getName().indexOf(".properties");
                    String lang = je.getName().substring(idx - 2, idx);
                    list.add(new Pair<String, String>(lang, new Locale(lang)
                        .getDisplayLanguage()));
                }
            }
        } catch (IOException ex) {
        }

        /* Search all files in the lang directory and add them */
        File[] files = (new File(Runtime.getInstance().getConfigPath() +
                "lang/")).listFiles();
        if (files != null) {
            for (File file : files) {
                String filename = file.getName();
                int idx = filename.indexOf(".properties");
                if (idx > -1) {
                    String lang = filename.substring(0, idx);
                    list.add(new Pair<String, String>(lang, new Locale(lang)
                        .getDisplayLanguage()));
                }
            }
        }

        return list;
    }
}