/*
* Copyright 2006 Assaf Arkin, Ralf Joachim
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* $Id: Messages.java 6907 2007-03-28 21:24:52Z rjoachim $
*/
package org.castor.core.util;
import java.text.MessageFormat;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Locale;
import java.util.MissingResourceException;
import java.util.ResourceBundle;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* I18N message formatting class. A static factory for obtaining
* messages and formatting messages with arguments.
* <p>
* The resource file <tt>org.exolab.castor.util.resources.messages</tt>
* contains a list of all the messages in English. Additional resource
* files can be added for other languages and locales by placing them
* in the same package with a language/locale prefix. See the I18N
* documentation and use of resource bundles in the JDK docs.
*
* @author <a href="mailto:arkin AT intalio DOT com">Assaf Arkin</a>
* @author <a href="mailto:ralf DOT joachim AT syscon DOT eu">Ralf Joachim</a>
* @version $Revision: 6907 $ $Date: 2006-04-10 16:39:24 -0600 (Mon, 10 Apr 2006) $
* @since 1.0.1
*/
public final class Messages {
//--------------------------------------------------------------------------
/** The <a href="http://jakarta.apache.org/commons/logging/">Jakarta Commons
* Logging </a> instance used for all logging. */
private static final Log LOG = LogFactory.getLog(Messages.class);
/** The name of the resource holding all the messages in the English
* language. Resources for other languages and locales use the same
* name with a language/locale prefix. */
public static final String RESOURCE_NAME = "org.castor.messages";
/** The resource bundle holds all the messages. */
private static ResourceBundle _messages;
/** Once a format has been created once, it is cached here. */
private static Hashtable _formats;
//--------------------------------------------------------------------------
static { setDefaultLocale(); }
//--------------------------------------------------------------------------
/**
* Set the default locale to use for loading messages. Calling this method
* will reload all the messages based on the new locale name.
*/
public static void setDefaultLocale() {
setLocale(Locale.getDefault());
}
/**
* Set the locale to use for loading messages. Calling this method
* will reload all the messages based on the new locale name.
*
* @param locale the locale for which a resource bundle is desired.
*/
public static void setLocale(final Locale locale) {
try {
_messages = ResourceBundle.getBundle(RESOURCE_NAME, locale);
} catch (Exception except) {
_messages = new EmptyResourceBundle();
LOG.error("Failed to locate messages resource " + RESOURCE_NAME);
}
_formats = new Hashtable();
}
/**
* Format the named message using a single argument and return the
* full message text.
*
* @param message The message name
* @param arg1 The first argument
* @return The full message text
*/
public static String format(final String message, final Object arg1) {
return format(message, new Object[] {arg1});
}
/**
* Format the named message using two argument and return the
* full message text.
*
* @param message The message name
* @param arg1 The first argument
* @param arg2 The second argument
* @return The full message text
*/
public static String format(final String message,
final Object arg1, final Object arg2) {
return format(message, new Object[] {arg1, arg2});
}
/**
* Format the named message using three argument and return the
* full message text.
*
* @param message The message name
* @param arg1 The first argument
* @param arg2 The second argument
* @param arg3 The third argument
* @return The full message text
*/
public static String format(final String message,
final Object arg1, final Object arg2, final Object arg3) {
return format(message, new Object[] {arg1, arg2, arg3});
}
/**
* Format the named message using any number of arguments and return the
* full message text.
*
* @param message The message name
* @param args Argument list
* @return The full message text
*/
public static String format(final String message, final Object[] args) {
try {
MessageFormat mf = (MessageFormat) _formats.get(message);
if (mf == null) {
String msg;
try {
msg = _messages.getString(message);
} catch (MissingResourceException except) {
return message;
}
mf = new MessageFormat(msg);
_formats.put(message, mf);
}
return mf.format(args);
} catch (Exception except) {
return "An internal error occured while processing message " + message;
}
}
/**
* Return the text of the named message without formatting.
*
* @param message The message name
* @return The full message text
*/
public static String message(final String message) {
try {
return _messages.getString(message);
} catch (MissingResourceException except) {
return message;
}
}
//--------------------------------------------------------------------------
/**
* Hide default constructor of utility class.
*/
private Messages() { }
//--------------------------------------------------------------------------
/**
* A empty resource bundle.
*/
private static class EmptyResourceBundle
extends ResourceBundle implements Enumeration {
/**
* {@inheritDoc}
* @see java.util.ResourceBundle#getKeys()
*/
public Enumeration getKeys() {
return this;
}
/**
* {@inheritDoc}
* @see java.util.ResourceBundle#handleGetObject(java.lang.String)
*/
protected Object handleGetObject(final String name) {
return "[Missing message " + name + "]";
}
/**
* {@inheritDoc}
* @see java.util.Enumeration#hasMoreElements()
*/
public boolean hasMoreElements() {
return false;
}
/**
* {@inheritDoc}
* @see java.util.Enumeration#nextElement()
*/
public Object nextElement() {
return null;
}
}
//--------------------------------------------------------------------------
}