org.xnap.commons.i18n.I18nManager Maven / Gradle / Ivy
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/*
* Gettext Commons
*
* Copyright (C) 2005 Felix Berger
* Copyright (C) 2005 Steffen Pingel
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package org.xnap.commons.i18n;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
/**
* Manager class that maintains a set of {@link org.xnap.commons.i18n.I18n}
* objects and {@link org.xnap.commons.i18n.LocaleChangeListener} objects.
*
* The locale of all managed I18n objects can be changed by
* invoking {@link org.xnap.commons.i18n.I18nManager#setDefaultLocale(Locale)}.
*
* @author Felix Berger
* @author Steffen Pingel
* @since 0.9
*/
public class I18nManager {
private static I18nManager instance = new I18nManager();
/** List of managed {@link I18n} objects. */
List i18ns = Collections.synchronizedList(new ArrayList());
/** List of managed {@link LocaleChangeListener} objects. */
List localeChangeListeners = new ArrayList();
private I18nManager()
{
}
/**
* Returns the global I18Manger singleton.
*
* @return the I18Manger instance
* @since 0.9
*/
public static I18nManager getInstance()
{
return instance;
}
/**
* Adds i18n to the list of managed I18n
* objects.
*
* @param i18n
* the I18n instance
* @see #setDefaultLocale(Locale)
* @see #remove(I18n)
* @since 0.9
*/
public void add(I18n i18n)
{
i18ns.add(i18n);
}
/**
* Sets the locale for all I18n instances that were instantiated through the
* factory.
*
* Use this method to globally change the locale for all I18n based
* translations.
*
* NOTE: This only works if the objects that display messages do not cache
* translated messages.
*
*
* @param locale
* the new default locale
* @see I18n#setLocale(Locale)
* @since 0.9
*/
public void setDefaultLocale(Locale locale)
{
synchronized (i18ns) {
for (Iterator it = i18ns.iterator(); it.hasNext();) {
I18n i18n = (I18n)it.next();
i18n.setLocale(locale);
}
}
fireLocaleChangedEvent(locale);
}
/**
* Adds a listener that is notified when the default locale has been
* changed.
*
* @param listener
* the listener
* @see #setDefaultLocale(Locale)
* @since 0.9
*/
public void addLocaleChangeListener(LocaleChangeListener listener)
{
synchronized (localeChangeListeners) {
localeChangeListeners.add(listener);
}
}
/**
* Adds a listener that is notified when the default locale has been changed
* using a {@link WeakReference}. The listener is removed when it has been
* cleaned up by the garbage collection.
*
* This is useful for temporary objects that may have an indeterminate
* lifetime such as dialogs.
*
* @param listener
* the listener
* @see #setDefaultLocale(Locale)
* @since 0.9
*/
public void addWeakLocaleChangeListener(LocaleChangeListener listener)
{
synchronized (localeChangeListeners) {
localeChangeListeners.add(new WeakLocaleChangeListener(listener));
}
}
/**
* Removes i18n from the list of managed I18n
* objects.
*
* @param i18n
* the I18n instance
* @see #add(I18n)
* @since 0.9
*/
public void remove(I18n i18n)
{
i18ns.remove(i18n);
}
/**
* Removes listener from the list of objects that are
* notified when the locale has changed.
*
* @param listener
* the listener
* @since 0.9
*/
public void removeLocaleChangeListener(LocaleChangeListener listener)
{
synchronized (localeChangeListeners) {
localeChangeListeners.remove(listener);
}
}
/**
* Notifies listeners of a locale change.
*
* @param newLocale
* new locale
* @since 0.9
*/
protected void fireLocaleChangedEvent(Locale newLocale)
{
LocaleChangeListener[] listeners;
synchronized (localeChangeListeners) {
listeners = (LocaleChangeListener[])localeChangeListeners.toArray(new LocaleChangeListener[0]);
}
if (listeners.length > 0) {
LocaleChangeEvent event = new LocaleChangeEvent(I18nFactory.class, newLocale);
for (int i = listeners.length - 1; i >= 0; i--) {
listeners[i].localeChanged(event);
}
}
}
private static class WeakLocaleChangeListener implements LocaleChangeListener {
private WeakReference reference;
public WeakLocaleChangeListener(LocaleChangeListener listener)
{
reference = new WeakReference(listener);
}
public void localeChanged(LocaleChangeEvent event)
{
Object listener = reference.get();
if (listener != null) {
((LocaleChangeListener)listener).localeChanged(event);
}
else {
I18nManager.getInstance().removeLocaleChangeListener(this);
}
}
}
}