/*

 * Copyright 1997-2002 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package javax.accessibility;

import java.util.Enumeration;

import java.util.Hashtable;

import java.util.Vector;

import java.util.Locale;

import java.util.MissingResourceException;

import java.util.ResourceBundle;

/**

 * <p>Base class used to maintain a strongly typed enumeration.  This is

 * the superclass of {@link AccessibleState} and {@link AccessibleRole}.

 * <p>The toDisplayString method allows you to obtain the localized string

 * for a locale independent key from a predefined ResourceBundle for the

 * keys defined in this class.  This localized string is intended to be

 * readable by humans.

 *

 * @see AccessibleRole

 * @see AccessibleState

 *

 * @author      Willie Walker

 * @author      Peter Korn

 * @author      Lynn Monsanto

 */

public abstract class AccessibleBundle {

    private static Hashtable table = new Hashtable();

    private final String defaultResourceBundleName

        = "com.sun.accessibility.internal.resources.accessibility";

    public AccessibleBundle() {

    }

    /**

     * The locale independent name of the state.  This is a programmatic

     * name that is not intended to be read by humans.

     * @see #toDisplayString

     */

    protected String key = null;

    /**

     * Obtains the key as a localized string.

     * If a localized string cannot be found for the key, the

     * locale independent key stored in the role will be returned.

     * This method is intended to be used only by subclasses so that they

     * can specify their own resource bundles which contain localized

     * strings for their keys.

     * @param resourceBundleName the name of the resource bundle to use for

     * lookup

     * @param locale the locale for which to obtain a localized string

     * @return a localized String for the key.

     */

    protected String toDisplayString(String resourceBundleName,

                                     Locale locale) {

        // loads the resource bundle if necessary

        loadResourceBundle(resourceBundleName, locale);

        // returns the localized string

        Object o = table.get(locale);

        if (o != null && o instanceof Hashtable) {

                Hashtable resourceTable = (Hashtable) o;

                o = resourceTable.get(key);

                if (o != null && o instanceof String) {

                    return (String)o;

                }

        }

        return key;

    }

    /**

     * Obtains the key as a localized string.

     * If a localized string cannot be found for the key, the

     * locale independent key stored in the role will be returned.

     *

     * @param locale the locale for which to obtain a localized string

     * @return a localized String for the key.

     */

    public String toDisplayString(Locale locale) {

        return toDisplayString(defaultResourceBundleName, locale);

    }

    /**

     * Gets localized string describing the key using the default locale.

     * @return a localized String describing the key for the default locale

     */

    public String toDisplayString() {

        return toDisplayString(Locale.getDefault());

    }

    /**

     * Gets localized string describing the key using the default locale.

     * @return a localized String describing the key using the default locale

     * @see #toDisplayString

     */

    public String toString() {

        return toDisplayString();

    }

    /*

     * Loads the Accessibility resource bundle if necessary.

     */

    private void loadResourceBundle(String resourceBundleName,

                                    Locale locale) {

        if (! table.contains(locale)) {

            try {

                Hashtable resourceTable = new Hashtable();

                ResourceBundle bundle = ResourceBundle.getBundle(resourceBundleName, locale);

                Enumeration iter = bundle.getKeys();

                while(iter.hasMoreElements()) {

                    String key = (String)iter.nextElement();

                    resourceTable.put(key, bundle.getObject(key));

                }

                table.put(locale, resourceTable);

            }

            catch (MissingResourceException e) {

                System.err.println("loadResourceBundle: " + e);

                // Just return so toDisplayString() returns the

                // non-localized key.

                return;

            }

        }

    }

}