/*

 * Copyright (c) 1996, 2006, 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 java.io.InputStream;

import java.io.Reader;

import java.io.IOException;

/**

 * <code>PropertyResourceBundle</code> is a concrete subclass of

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

 * using a set of static strings from a property file. See

 * {@link ResourceBundle ResourceBundle} for more information about resource

 * bundles.

 *

 * <p>

 * Unlike other types of resource bundle, you don't subclass

 * <code>PropertyResourceBundle</code>.  Instead, you supply properties

 * files containing the resource data.  <code>ResourceBundle.getBundle</code>

 * will automatically look for the appropriate properties file and create a

 * <code>PropertyResourceBundle</code> that refers to it. See

 * {@link ResourceBundle#getBundle(java.lang.String, java.util.Locale, java.lang.ClassLoader) ResourceBundle.getBundle}

 * for a complete description of the search and instantiation strategy.

 *

 * <p>

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

 * bundle family with the base name "MyResources".

 * The text defines the bundle "MyResources_de",

 * the German member of the bundle family.

 * This member is based on <code>PropertyResourceBundle</code>, and the text

 * therefore is the content of the file "MyResources_de.properties"

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

 * how you can add bundles to this family that are implemented as subclasses

 * of <code>ListResourceBundle</code>).

 * 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>

 * # MessageFormat pattern

 * s1=Die Platte \"{1}\" enthält {0}.

 *

 * # location of {0} in pattern

 * s2=1

 *

 * # sample disk name

 * s3=Meine Platte

 *

 * # first ChoiceFormat choice

 * s4=keine Dateien

 *

 * # second ChoiceFormat choice

 * s5=eine Datei

 *

 * # third ChoiceFormat choice

 * s6={0,number} Dateien

 *

 * # sample date

 * s7=3. März 1996

 * </pre>

 * </blockquote>

 *

 * <p>

 * <strong>Note:</strong> PropertyResourceBundle can be constructed either

 * from an InputStream or a Reader, which represents a property file.

 * Constructing a PropertyResourceBundle instance from an InputStream requires

 * that the input stream be encoded in ISO-8859-1.  In that case, characters

 * that cannot be represented in ISO-8859-1 encoding must be represented by Unicode Escapes

 * as defined in section 3.3 of

 * <cite>The Java&trade; Language Specification</cite>

 * whereas the other constructor which takes a Reader does not have that limitation.

 *

 * @see ResourceBundle

 * @see ListResourceBundle

 * @see Properties

 * @since JDK1.1

 */

public class PropertyResourceBundle extends ResourceBundle {

    /**

     * Creates a property resource bundle from an {@link java.io.InputStream

     * InputStream}.  The property file read with this constructor

     * must be encoded in ISO-8859-1.

     *

     * @param stream an InputStream that represents a property file

     *        to read from.

     * @throws IOException if an I/O error occurs

     * @throws NullPointerException if <code>stream</code> is null

     */

    public PropertyResourceBundle (InputStream stream) throws IOException {

        Properties properties = new Properties();

        properties.load(stream);

        lookup = new HashMap(properties);

    }

    /**

     * Creates a property resource bundle from a {@link java.io.Reader

     * Reader}.  Unlike the constructor

     * {@link #PropertyResourceBundle(java.io.InputStream) PropertyResourceBundle(InputStream)},

     * there is no limitation as to the encoding of the input property file.

     *

     * @param reader a Reader that represents a property file to

     *        read from.

     * @throws IOException if an I/O error occurs

     * @throws NullPointerException if <code>reader</code> is null

     * @since 1.6

     */

    public PropertyResourceBundle (Reader reader) throws IOException {

        Properties properties = new Properties();

        properties.load(reader);

        lookup = new HashMap(properties);

    }

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

    public Object handleGetObject(String key) {

        if (key == null) {

            throw new NullPointerException();

        }

        return lookup.get(key);

    }

    /**

     * 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() {

        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() {

        return lookup.keySet();

    }

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

    private Map<String,Object> lookup;

    /**

     * Implements an Enumeration that combines elements from a Set and

     * an Enumeration. Used by ListResourceBundle and PropertyResourceBundle.

     */

    static class ResourceBundleEnumeration implements Enumeration<String> {

        Set<String> set;

        Iterator<String> iterator;

        Enumeration<String> enumeration; // may remain null

        /**

         * Constructs a resource bundle enumeration.

         * @param set an set providing some elements of the enumeration

         * @param enumeration an enumeration providing more elements of the enumeration.

         *        enumeration may be null.

         */

        public ResourceBundleEnumeration(Set<String> set, Enumeration<String> enumeration) {

            this.set = set;

            this.iterator = set.iterator();

            this.enumeration = enumeration;

        }

        String next = null;

        public boolean hasMoreElements() {

            if (next == null) {

                if (iterator.hasNext()) {

                    next = iterator.next();

                } else if (enumeration != null) {

                    while (next == null && enumeration.hasMoreElements()) {

                        next = enumeration.nextElement();

                        if (set.contains(next)) {

                            next = null;

                        }

                    }

                }

            }

            return next != null;

        }

        public String nextElement() {

            if (hasMoreElements()) {

                String result = next;

                next = null;

                return result;

            } else {

                throw new NoSuchElementException();

            }

        }

    }

}