Fix location bundle with fast access (#3327)

* Made the LocalizationBundle a private class of Localization and ensured, that all accesses to it are only lookups in hashmaps

Made all access of Location-messages a fast hash table lookup.
Fixed one message in JabRefFrame that used an escaped key instead of the unescaped version.

* Fix NPE in MainTable (#3318)

* Fix NPE in MainTable

* Fix build

* Use of HashMap instead of Hashtable
General code cleanup

* Forgot to replace one null test

* Reordering of import statements and fields
Replacement of last null test with Objects.requireNonNull

src/main/java/org/jabref/JabRefMain.java

@@ -66,7 +66,9 @@ private static void start(String[] args) {
 
         Globals.prefs = preferences;
         Globals.startBackgroundTasks();
-        Localization.setLanguage(preferences.get(JabRefPreferences.LANGUAGE));
+
+        // Note that the language was already set during the initialization of the preferences and it is safe to
+        // call the next function.
         Globals.prefs.setLanguageDependentDefaultValues();
 
         // Perform Migrations

src/main/java/org/jabref/gui/JabRefFrame.java

@@ -254,8 +254,8 @@ public class JabRefFrame extends JFrame implements OutputPrinter {
             Globals.getKeyPrefs().getKey(KeyBinding.OPEN_CONSOLE),
             IconTheme.JabRefIcon.CONSOLE.getIcon());
     private final AbstractAction pullChangesFromSharedDatabase = new GeneralAction(Actions.PULL_CHANGES_FROM_SHARED_DATABASE,
-            Localization.menuTitle("Pull_changes_from_shared_database"),
-            Localization.lang("Pull_changes_from_shared_database"),
+            Localization.menuTitle("Pull changes from shared database"),
+            Localization.lang("Pull changes from shared database"),
             Globals.getKeyPrefs().getKey(KeyBinding.PULL_CHANGES_FROM_SHARED_DATABASE),
             IconTheme.JabRefIcon.PULL.getIcon());
     private final AbstractAction mark = new GeneralAction(Actions.MARK_ENTRIES, Localization.menuTitle("Mark entries"),

src/main/java/org/jabref/logic/l10n/Localization.java

@@ -1,41 +1,103 @@
 package org.jabref.logic.l10n;
 
 import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Enumeration;
+import java.util.HashMap;
 import java.util.Locale;
 import java.util.MissingResourceException;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.ResourceBundle;
+import java.util.Set;
+import java.util.stream.Collectors;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+/**
+ * Provides handling for messages and menu entries in the preferred language of the user.
+ * <p>
+ * Notes: All messages and menu-entries in JabRef are stored in escaped form like "This_is_a_message". This message
+ * serves as key inside the {@link l10n} properties files that hold the translation for many languages. When a message
+ * is accessed, it needs to be unescaped and possible parameters that can appear in a message need to be filled with
+ * values.
+ * <p>
+ * This implementation loads the appropriate language by importing all keys/values from the correct bundle and stores
+ * them in unescaped form inside a {@link LocalizationBundle} which provides fast access because it caches the key-value
+ * pairs.
+ * <p>
+ * The access to this is given by the functions {@link Localization#lang(String, String...)} and {@link
+ * Localization#menuTitle(String, String...)} that developers should use whenever they use strings for the e.g. GUI that
+ * need to be translatable.
+ */
 public class Localization {
-    public static final String RESOURCE_PREFIX = "l10n/JabRef";
-    public static final String MENU_RESOURCE_PREFIX = "l10n/Menu";
     public static final String BIBTEX = "BibTeX";
+    static final String RESOURCE_PREFIX = "l10n/JabRef";
+    static final String MENU_RESOURCE_PREFIX = "l10n/Menu";
 
     private static final Log LOGGER = LogFactory.getLog(Localization.class);
 
-    private static ResourceBundle messages;
-    private static ResourceBundle menuTitles;
+    private static Locale locale;
+    private static LocalizationBundle localizedMessages;
+    private static LocalizationBundle localizedMenuTitles;
 
     private Localization() {
     }
 
-    public static LocalizationBundle getMessages() {
-        return new LocalizationBundle(messages);
+    /**
+     * Public access to all messages that are not menu-entries
+     *
+     * @param key    The key of the message in unescaped form like "All fields"
+     * @param params Replacement strings for parameters %0, %1, etc.
+     * @return The message with replaced parameters
+     */
+    public static String lang(String key, String... params) {
+        if (localizedMessages == null) {
+            // I'm logging this because it should never happen
+            LOGGER.error("Messages are not initialized.");
+            setLanguage("en");
+        }
+        return lookup(localizedMessages, "message", key, params);
+    }
+
+    /**
+     * Public access to menu entry messages
+     *
+     * @param key    The key of the message in unescaped form like "Save all"
+     * @param params Replacement strings for parameters %0, %1, etc.
+     * @return The message with replaced parameters
+     */
+    public static String menuTitle(String key, String... params) {
+        if (localizedMenuTitles == null) {
+            // I'm logging this because it should never happen
+            LOGGER.error("Menu entries are not initialized");
+            setLanguage("en");
+        }
+        return lookup(localizedMenuTitles, "menu item", key, params);
     }
 
+    /**
+     * Sets the language and loads the appropriate translations. Note, that this function should be called before any
+     * other function of this class.
+     *
+     * @param language Language identifier like "en", "de", etc.
+     */
     public static void setLanguage(String language) {
         Optional<Locale> knownLanguage = Languages.convertToSupportedLocale(language);
+        final Locale defaultLocale = Locale.getDefault();
         if (!knownLanguage.isPresent()) {
-            LOGGER.warn("Language " + language + " is not supported by JabRef (Default:" + Locale.getDefault() + ")");
+            LOGGER.warn("Language " + language + " is not supported by JabRef (Default:" + defaultLocale + ")");
             setLanguage("en");
             return;
         }
-
-        Locale locale = knownLanguage.get();
+        // avoid reinitialization of the language bundles
+        final Locale langLocale = knownLanguage.get();
+        if ((locale != null) && locale.equals(langLocale) && locale.equals(defaultLocale)) {
+            return;
+        }
+        locale = langLocale;
         Locale.setDefault(locale);
         javax.swing.JComponent.setDefaultLocale(locale);
 
@@ -48,54 +110,103 @@ public static void setLanguage(String language) {
         }
     }
 
+    /**
+     * Public access to the messages bundle for classes like AbstractView.
+     *
+     * @return The internally cashed bundle.
+     */
+    public static LocalizationBundle getMessages() {
+        // avoid situations where this function is called before any language was set
+        if (locale == null) {
+            setLanguage("en");
+        }
+        return localizedMessages;
+    }
+
+    /**
+     * Creates and caches the language bundles used in JabRef for a particular language. This function first loads
+     * correct version of the "escaped" bundles that are given in {@link l10n}. After that, it stores the unescaped
+     * version in a cached {@link LocalizationBundle} for fast access.
+     *
+     * @param locale Localization to use.
+     */
     private static void createResourceBundles(Locale locale) {
-        messages = ResourceBundle.getBundle(RESOURCE_PREFIX, locale, new EncodingControl(StandardCharsets.UTF_8));
-        menuTitles = ResourceBundle.getBundle(MENU_RESOURCE_PREFIX, locale, new EncodingControl(StandardCharsets.UTF_8));
+        ResourceBundle messages = ResourceBundle.getBundle(RESOURCE_PREFIX, locale, new EncodingControl(StandardCharsets.UTF_8));
+        ResourceBundle menuTitles = ResourceBundle.getBundle(MENU_RESOURCE_PREFIX, locale, new EncodingControl(StandardCharsets.UTF_8));
+        Objects.requireNonNull(messages, "Could not load " + RESOURCE_PREFIX + " resource.");
+        Objects.requireNonNull(menuTitles, "Could not load " + MENU_RESOURCE_PREFIX + " resource.");
+        localizedMessages = new LocalizationBundle(createLookupMap(messages));
+        localizedMenuTitles = new LocalizationBundle(createLookupMap(menuTitles));
     }
 
     /**
-     * In the translation, %0, ..., %9 is replaced by the respective params given
+     * Helper function to create a HashMap from the key/value pairs of a bundle.
      *
-     * @param resBundle         the ResourceBundle to use
-     * @param idForErrorMessage output when translation is not found
-     * @param key               the key to lookup in resBundle
-     * @param params            a list of Strings to replace %0, %1, ...
-     * @return
+     * @param baseBundle JabRef language bundle with keys and values for translations.
+     * @return Lookup map for the baseBundle.
      */
-    protected static String translate(ResourceBundle resBundle, String idForErrorMessage, String key, String... params) {
-        Objects.requireNonNull(resBundle);
+    private static HashMap<String, String> createLookupMap(ResourceBundle baseBundle) {
+        final ArrayList<String> baseKeys = Collections.list(baseBundle.getKeys());
+        return new HashMap<>(baseKeys.stream().collect(
+                Collectors.toMap(
+                        key -> new LocalizationKey(key).getTranslationValue(),
+                        key -> new LocalizationKey(baseBundle.getString(key)).getTranslationValue())
+        ));
+    }
 
-        String translation = null;
-        try {
-            String propertiesKey = new LocalizationKey(key).getPropertiesKeyUnescaped();
-            translation = resBundle.getString(propertiesKey);
-        } catch (MissingResourceException ex) {
+    /**
+     * This looks up a key in the bundle and replaces parameters %0, ..., %9 with the respective params given. Note that
+     * the keys are the "unescaped" strings from the bundle property files.
+     *
+     * @param bundle            The {@link LocalizationBundle} which means either {@link Localization#localizedMenuTitles}
+     *                          or {@link Localization#localizedMessages}.
+     * @param idForErrorMessage Identifier-string when the translation is not found.
+     * @param key               The lookup key.
+     * @param params            The parameters that should be inserted into the message
+     * @return The final message with replaced parameters.
+     */
+    private static String lookup(LocalizationBundle bundle, String idForErrorMessage, String key, String... params) {
+        Objects.requireNonNull(key);
+
+        String translation = bundle.containsKey(key) ? bundle.getString(key) : "";
+        if (translation.isEmpty()) {
             LOGGER.warn("Warning: could not get " + idForErrorMessage + " translation for \"" + key + "\" for locale "
                     + Locale.getDefault());
-        }
-        if ((translation == null) || translation.isEmpty()) {
-            LOGGER.warn("Warning: no " + idForErrorMessage + " translation for \"" + key + "\" for locale "
-                    + Locale.getDefault());
-
             translation = key;
         }
-
         return new LocalizationKeyParams(translation, params).replacePlaceholders();
     }
 
-    public static String lang(String key, String... params) {
-        if (messages == null) {
-            setLanguage("en");
+    /**
+     * A bundle for caching localized strings. Needed to support JavaFX inline binding.
+     */
+    private static class LocalizationBundle extends ResourceBundle {
+
+        private final HashMap<String, String> lookup;
+
+        LocalizationBundle(HashMap<String, String> lookupMap) {
+            lookup = lookupMap;
         }
-        return translate(messages, "message", key, params);
-    }
 
-    public static String menuTitle(String key, String... params) {
-        if (menuTitles == null) {
-            setLanguage("en");
+        public final Object handleGetObject(String key) {
+            Objects.requireNonNull(key);
+            return lookup.get(key);
+        }
+
+        @Override
+        public Enumeration<String> getKeys() {
+            return Collections.enumeration(lookup.keySet());
         }
-        return translate(menuTitles, "menu item", key, params);
-    }
 
+        @Override
+        protected Set<String> handleKeySet() {
+            return lookup.keySet();
+        }
+
+        @Override
+        public boolean containsKey(String key) {
+            return (key != null) && lookup.containsKey(key);
+        }
+    }
 }
 

src/main/java/org/jabref/preferences/JabRefPreferences.java

@@ -447,6 +447,12 @@ private JabRefPreferences() {
         // load user preferences
         prefs = Preferences.userNodeForPackage(PREFS_BASE_CLASS);
 
+        // Since some of the preference settings themselves use localized strings, we cannot set the language after
+        // the initialization of the preferences in main
+        // Otherwise that language framework will be instantiated and more importantly, statically initialized preferences
+        // like the SearchDisplayMode will never be translated.
+        Localization.setLanguage(prefs.get(LANGUAGE, "en"));
+
         SearchPreferences.putDefaults(defaults);
 
         defaults.put(TEXMAKER_PATH, JabRefDesktop.getNativeDesktop().detectProgramPath("texmaker", "Texmaker"));