translator.java

用JGraph编的软件

/*
 * @(#)Translator.java	1.0 23/01/02
 *
 * Copyright (C) 2003 Sven Luzar
 *
 * 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.jgraph.pad.resources;

import java.text.MessageFormat;
import java.util.Enumeration;
import java.util.Locale;
import java.util.MissingResourceException;
import java.util.PropertyResourceBundle;
import java.util.ResourceBundle;
import java.util.Stack;
import java.util.Vector;

/** Contains ResourceBundle objects.
 *  The first (deepest) bundle is the Graphpad bundle.
 *  If a user wants to use Graphpad as a framework
 *  he can push his own bundle with the <tt>pushBundle</tt>
 *  method. Requests will procedure with the following
 *  logic: The translator asks the highest bundle
 *  for a localized text string. If the bundle has
 *  no entry for the specified key. The next bundle will
 *  ask for the key. If the deepest bundle hasn't a
 *  value for the key the key will return.
 *
 * @author <a href="mailto:[e-mail]">Sven luzar</a>
 * @version 1.0
 * @see #pushBundle
 */

public class Translator {

	/** Container for the registered LocaleChangeListener.
	 *  @see LocaleChangeListener
	 */
	protected static Vector listeners = new Vector();

	/** The translator creates outputs on the
	 *  System.err if a resource wasn't found and
	 *  this boolean is <tt>true</tt>
	 */
	protected static boolean logNotFoundResources = false;

	/** Contains ResourceBundle objects.
	 *  The first bundle is the Graphpad bundle.
	 *  If a user wants to use Graphpad as a framework
	 *  he can push his own bundle.
	 */
	protected static Stack bundles = new Stack();

	/** Contains ResourceBundle names
	 *  The first bundlename is the Graphpad bundle.
	 *  If a user wants to use Graphpad as a framework
	 *  he can push his own bundle.
	 */
	protected static Stack bundleNames = new Stack();
	
    /**
	 * Resouce Bundle with proper names.
	 */
    protected static DefaultResourceBundle defaultBundle = new DefaultResourceBundle();

	/** Returns the resouce bundle with the proper names.
	 *
	 */
	public static DefaultResourceBundle getDefaultResourceBundle(){
	  return defaultBundle;
	}


	/** pushes the default bundle for graphpad
	 *  to the stack
	 *  @see #pushBundle
	 */
	static {
		pushBundle("org.jgraph.pad.resources.Graphpad");
	}

	/** Returns the localized String for the key. If
	 *  the String wasn't found the method will return
	 *  the Key but not null.
	 *
	 *  @param sKey Key for the localized String.
	 *
	 */
	public static String getString(String sKey) {
		return getString(bundles.size()-1, sKey);
	}

	/** Returns the localized String for the key. If
	 *  the String wasn't found the method will return
	 *  null.
	 *
	 *  @param bundleIndex The bundle index for the request.
	 *                      The method requests the bundle
	 *                      at the specified position and
	 *                      at all deeper positions.
	 *
	 *  @param sKey Key for the localized String.
	 *
	 */
	public static String getString(int bundleIndex, String sKey) {
		if (bundleIndex < bundles.size() && bundleIndex >= 0){
			ResourceBundle bundle = (ResourceBundle)bundles.get(bundleIndex);
			try {
				return bundle.getString(sKey);
			} catch (MissingResourceException mrex) {
				return getString(bundleIndex-1, sKey);
			}
		} else {
			try {
				return defaultBundle.getString(sKey);
			} catch (MissingResourceException mrex) {
				if (logNotFoundResources)
						System.err.println("Resource for the following key not found:" + sKey);
				return null;
			}
		}
	}

	/** Returns the localized String for the key. If
	*  the String wasn't found the method will return
	*  the key but not null.
	*
	*  @param sKey Key for the localized String.
	*  @param oValues Object array for placeholders.
	*
	*  @see MessageFormat#format(String, Object[])
	*/
	public static String getString(String sKey, Object[] values) {
		return getString(bundles.size()-1, sKey, values);
	}

	/** Returns the localized String for the key. If
	 *  the String wasn't found the method will return
	 *  an empty String but not null and will log
	 *  on the System.err the key String,
	 *  if logNotFoundResources is true.
	 *
	 *  @param sKey Key for the localized String.
	 *  @param logNotFoundResources
	 *         if true and the key wasn't found a message
	 *         will print on the System.err.
	 *  @param oValues Object array for placeholders.
	 *
	 *  @see MessageFormat#format(String, Object[])
	 */
	public static String getString(
		int bundleIndex,
		String sKey,
		Object[] oValues
		) {

		if (bundleIndex < bundles.size() && bundleIndex >= 0){
			ResourceBundle bundle = (ResourceBundle)bundles.get(bundleIndex);
			try {
				return MessageFormat.format(bundle.getString(sKey), oValues);
			} catch (MissingResourceException mrex) {
				return getString(bundleIndex-1, sKey, oValues);
			}
		} else {
			try {
				return defaultBundle.getString(sKey);
			} catch (MissingResourceException mrex) {
				if (logNotFoundResources)
						System.err.println("Resource for the following key not found:" + sKey);
				return null;
			}
		}
	}

	/**
	 * Adds a locale change listener to this Translator. If
	 * the local changes, this
	 * translator will fire locale change events.
	 *
	 */
	public static void addLocaleChangeListener(LocaleChangeListener listener) {
		listeners.add(listener);
	}

	/** Removes the registered Listener
	 *
	 */
	public static void removeLocaleChangeListener(LocaleChangeListener listener) {
		listeners.remove(listener);
	}

	/** Returns the current locale
	 *
	 */
	public static Locale getLocale() {
		return Locale.getDefault();
	}

	/** Sets the new locale and fires events
	 *  to the locale change listener.
	 *
	 */
	public static void setLocale(Locale locale) {
		// change the locale
		Locale oldLocale = Locale.getDefault();
		Locale.setDefault(locale);

		// reload the bundles
		reloadBundles();

		// update listeners
		Vector cpyListeners;
		synchronized (listeners) {
			cpyListeners = (Vector) listeners.clone();
		}

		Enumeration oEnum = cpyListeners.elements();
		while (oEnum.hasMoreElements()) {
			LocaleChangeListener listener =
				(LocaleChangeListener) oEnum.nextElement();
			listener.localeChanged(new LocaleChangeEvent(oldLocale, locale));
		}
	}

	/** 
	 * 
	 * Reloads the bundles at the stack by using the default locale.
	 */
	public static void reloadBundles(){
		// update the proper bundles		
		defaultBundle.requeryDefaultNames();
		
		// update the bundles at the stack		
		for (int i = 0; i < bundleNames.size() ; i++){
			ResourceBundle resourcebundle =
				PropertyResourceBundle.getBundle((String)bundleNames.get(i));
			bundles.set( i, resourcebundle);
		}
	}

	/** Pushes the specified bundle on the stack.
	 *  An example for a bundle file name is 'org.jgraph.pad.resources.Graphpad'.
	 *  Don't add the suffix of the filename, the language or country code.
	 *  @see PropertyResourceBundle#getBundle
	 */
	public static void pushBundle(String filename){
		ResourceBundle resourcebundle =
			PropertyResourceBundle.getBundle(filename);
		bundles.push(resourcebundle);
		bundleNames.push( filename);
	}

	/** Pops the highest bundle on the stack
	 */
	public static void popBundle(){
		bundles.pop() ;
		bundleNames.pop() ;
	}

	/** removes the specified bundle
	 */
	public static void removeBundle(int index){
		bundles.remove(index) ;
		bundleNames.remove(index) ;
	}
	/**
	 * Returns the logNotFoundResources.
	 * @return boolean
	 */
	public static boolean isLogNotFoundResources() {
		return logNotFoundResources;
	}

	/**
	 * Sets the logNotFoundResources.
	 * @param logNotFoundResources The logNotFoundResources to set
	 */
	public static void setLogNotFoundResources(boolean logNotFoundResources) {
		Translator.logNotFoundResources = logNotFoundResources;
	}
}