/*

 * Copyright (c) 1996, 2013, Oracle and/or its affiliates. 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.  Oracle designates this

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

 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/*

 * (C) Copyright Taligent, Inc. 1996, 1997 - All Rights Reserved

 * (C) Copyright IBM Corp. 1996 - 1998 - All Rights Reserved

 *

 * The original version of this source code and documentation

 * is copyrighted and owned by Taligent, Inc., a wholly-owned

 * subsidiary of IBM. These materials are provided under terms

 * of a License Agreement between Taligent and Sun. This technology

 * is protected by multiple US and International patents.

 *

 * This notice and attribution to Taligent may not be removed.

 * Taligent is a registered trademark of Taligent, Inc.

 *

 */

package java.util;

import sun.util.ResourceBundleEnumeration;

/**

 * <code>ListResourceBundle</code> is an abstract subclass of

 * <code>ResourceBundle</code> that manages resources for a locale

 * in a convenient and easy to use list. See <code>ResourceBundle</code> for

 * more information about resource bundles in general.

 *

 * <P>

 * Subclasses must override <code>getContents</code> and provide an array,

 * where each item in the array is a pair of objects.

 * The first element of each pair is the key, which must be a

 * <code>String</code>, and the second element is the value associated with

 * that key.

 *

 * <p>

 * The following <a name="sample">example</a> shows two members of a resource

 * bundle family with the base name "MyResources".

 * "MyResources" is the default member of the bundle family, and

 * "MyResources_fr" is the French member.

 * These members are based on <code>ListResourceBundle</code>

 * (a related <a href="PropertyResourceBundle.html#sample">example</a> shows

 * how you can add a bundle to this family that's based on a properties file).

 * The keys in this example are of the form "s1" etc. The actual

 * keys are entirely up to your choice, so long as they are the same as

 * the keys you use in your program to retrieve the objects from the bundle.

 * Keys are case-sensitive.

 * <blockquote>

 * <pre>

 *

 * public class MyResources extends ListResourceBundle {

 *     protected Object[][] getContents() {

 *         return new Object[][] {

 *         // LOCALIZE THIS

 *             {"s1", "The disk \"{1}\" contains {0}."},  // MessageFormat pattern

 *             {"s2", "1"},                               // location of {0} in pattern

 *             {"s3", "My Disk"},                         // sample disk name

 *             {"s4", "no files"},                        // first ChoiceFormat choice

 *             {"s5", "one file"},                        // second ChoiceFormat choice

 *             {"s6", "{0,number} files"},                // third ChoiceFormat choice

 *             {"s7", "3 Mar 96"},                        // sample date

 *             {"s8", new Dimension(1,5)}                 // real object, not just string

 *         // END OF MATERIAL TO LOCALIZE

 *         };

 *     }

 * }

 *

 * public class MyResources_fr extends ListResourceBundle {

 *     protected Object[][] getContents() {

 *         return new Object[][] {

 *         // LOCALIZE THIS

 *             {"s1", "Le disque \"{1}\" {0}."},          // MessageFormat pattern

 *             {"s2", "1"},                               // location of {0} in pattern

 *             {"s3", "Mon disque"},                      // sample disk name

 *             {"s4", "ne contient pas de fichiers"},     // first ChoiceFormat choice

 *             {"s5", "contient un fichier"},             // second ChoiceFormat choice

 *             {"s6", "contient {0,number} fichiers"},    // third ChoiceFormat choice

 *             {"s7", "3 mars 1996"},                     // sample date

 *             {"s8", new Dimension(1,3)}                 // real object, not just string

 *         // END OF MATERIAL TO LOCALIZE

 *         };

 *     }

 * }

 * </pre>

 * </blockquote>

 *

 * <p>

 * The implementation of a {@code ListResourceBundle} subclass must be thread-safe

 * if it's simultaneously used by multiple threads. The default implementations

 * of the methods in this class are thread-safe.

 *

 * @see ResourceBundle

 * @see PropertyResourceBundle

 * @since 1.1

 */

public abstract class ListResourceBundle extends ResourceBundle {

    /**

     * Sole constructor.  (For invocation by subclass constructors, typically

     * implicit.)

     */

    public ListResourceBundle() {

    }

    // Implements java.util.ResourceBundle.handleGetObject; inherits javadoc specification.

    public final Object handleGetObject(String key) {

        // lazily load the lookup hashtable.

        if (lookup == null) {

            loadLookup();

        }

        if (key == null) {

            throw new NullPointerException();

        }

        return lookup.get(key); // this class ignores locales

    }

    /**

     * Returns an <code>Enumeration</code> of the keys contained in

     * this <code>ResourceBundle</code> and its parent bundles.

     *

     * @return an <code>Enumeration</code> of the keys contained in

     *         this <code>ResourceBundle</code> and its parent bundles.

     * @see #keySet()

     */

    public Enumeration<String> getKeys() {

        // lazily load the lookup hashtable.

        if (lookup == null) {

            loadLookup();

        }

        ResourceBundle parent = this.parent;

        return new ResourceBundleEnumeration(lookup.keySet(),

                (parent != null) ? parent.getKeys() : null);

    }

    /**

     * Returns a <code>Set</code> of the keys contained

     * <em>only</em> in this <code>ResourceBundle</code>.

     *

     * @return a <code>Set</code> of the keys contained only in this

     *         <code>ResourceBundle</code>

     * @since 1.6

     * @see #keySet()

     */

    protected Set<String> handleKeySet() {

        if (lookup == null) {

            loadLookup();

        }

        return lookup.keySet();

    }

    /**

     * Returns an array in which each item is a pair of objects in an

     * <code>Object</code> array. The first element of each pair is

     * the key, which must be a <code>String</code>, and the second

     * element is the value associated with that key.  See the class

     * description for details.

     *

     * @return an array of an <code>Object</code> array representing a

     * key-value pair.

     */

    abstract protected Object[][] getContents();

    // ==================privates====================

    /**

     * We lazily load the lookup hashtable.  This function does the

     * loading.

     */

    private synchronized void loadLookup() {

        if (lookup != null)

            return;

        Object[][] contents = getContents();

        HashMap<String,Object> temp = new HashMap<>(contents.length);

        for (Object[] content : contents) {

            // key must be non-null String, value must be non-null

            String key = (String) content[0];

            Object value = content[1];

            if (key == null || value == null) {

                throw new NullPointerException();

            }

            temp.put(key, value);

        }

        lookup = temp;

    }

    private Map<String,Object> lookup = null;

}