/*
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
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 *
 * 5. Products derived from this software may not be called "Apache"
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 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.taglibs.standard.resources;

import java.util.*;
import java.text.*;

/**
 * <p>Provides locale-neutral access to string resources.  Only the
 * documentation and code are in English. :-)
 *
 * <p>The major goal, aside from globalization, is convenience.
 * Access to resources with no parameters is made in the form:</p>
 * <pre>
 *     Resources.getMessage(MESSAGE_NAME);
 * </pre>
 *
 * <p>Access to resources with one parameter works like</p>
 * <pre>
 *     Resources.getMessage(MESSAGE_NAME, arg1);
 * </pre>
 *
 * <p>... and so on.</p>
 *
 * @author Shawn Bayern
 */
public class Resources {

    //*********************************************************************
    // Static data

    /** The location of our resources. */
    private static final String RESOURCE_LOCATION
	= "org.apache.taglibs.standard.resources.Resources";

    /** Our class-wide ResourceBundle. */
    private static ResourceBundle rb =
	ResourceBundle.getBundle(RESOURCE_LOCATION);

    private static Hashtable formats = new Hashtable();


    //*********************************************************************
    // Public static methods

    /** Retrieves a message with no arguments. */
    public static String getMessage(String name)
	    throws MissingResourceException {
	return rb.getString(name);
    }

    /** Retrieves a message with arbitrarily many arguments. */
    public static String getMessage(String name, Object[] a)
	    throws MissingResourceException {

        // MessageFormats are slow to initialize, but perform
        // the formating operation fairly quickly.  Caching the
        // formats will result in more speed.  However, if only
        // one format per message exists, high thread contention
        // for the same format could result in a slowdown on a
        // system with a heavy load.  Therefore, a simple pool
        // of formats will allow caching of parsed formats and
        // reduce the amount of time threads wait on each other.
        // Note: Hashtable and Stack are thread safe

        // Retrieve pre-parsed format pool for message
        Stack formatPool = (Stack) formats.get(name);
        if (formatPool==null) {
            formatPool = new Stack();
            formats.put(name, formatPool);
        }

        // Retrieve format from pool or create a new one if pool
        // is empty
        MessageFormat messageFormat = null;
        try {
            messageFormat = (MessageFormat) formatPool.pop();
        }
        catch(EmptyStackException emptyx) {
            messageFormat = new MessageFormat(rb.getString(name));
        }

        // Generate formatted message
        String message = messageFormat.format(a);

        // Put parsed format back in pool for re-use by
        // another thread
        formatPool.push(messageFormat);

        return message;
    }

    /** Retrieves a message with one argument. */
    public static String getMessage(String name, Object a1)
	    throws MissingResourceException {
	return getMessage(name, new Object[] { a1 });
    }

    /** Retrieves a message with two arguments. */
    public static String getMessage(String name, Object a1, Object a2)
	    throws MissingResourceException {
	return getMessage(name, new Object[] { a1, a2 });
    }

    /** Retrieves a message with three arguments. */
    public static String getMessage(String name,
				    Object a1,
				    Object a2,
				    Object a3)
	    throws MissingResourceException {
	return getMessage(name, new Object[] { a1, a2, a3 });
    }

    /** Retrieves a message with four arguments. */
    public static String getMessage(String name,
			 	    Object a1,
				    Object a2,
				    Object a3,
				    Object a4)
	    throws MissingResourceException {
	return getMessage(name, new Object[] { a1, a2, a3, a4 });
    }

    /** Retrieves a message with five arguments. */
    public static String getMessage(String name,
				    Object a1,
				    Object a2,
				    Object a3,
				    Object a4,
				    Object a5)
	    throws MissingResourceException {
	return getMessage(name, new Object[] { a1, a2, a3, a4, a5 });
    }

    /** Retrieves a message with six arguments. */
    public static String getMessage(String name,
				    Object a1,
				    Object a2,
				    Object a3,
				    Object a4,
				    Object a5,
				    Object a6)
	    throws MissingResourceException {
	return getMessage(name, new Object[] { a1, a2, a3, a4, a5, a6 });
    }

}