1/*
2 * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26/*
27 * (C) Copyright Taligent, Inc. 1996, 1997 - All Rights Reserved
28 * (C) Copyright IBM Corp. 1996 - 1998 - All Rights Reserved
29 *
30 * The original version of this source code and documentation
31 * is copyrighted and owned by Taligent, Inc., a wholly-owned
32 * subsidiary of IBM. These materials are provided under terms
33 * of a License Agreement between Taligent and Sun. This technology
34 * is protected by multiple US and International patents.
35 *
36 * This notice and attribution to Taligent may not be removed.
37 * Taligent is a registered trademark of Taligent, Inc.
38 *
39 */
40
41package sun.util.resources;
42
43import java.util.Enumeration;
44import java.util.HashMap;
45import java.util.HashSet;
46import java.util.Map;
47import java.util.ResourceBundle;
48import java.util.Set;
49import sun.util.ResourceBundleEnumeration;
50
51/**
52 * Subclass of <code>ResourceBundle</code> which mimics
53 * <code>ListResourceBundle</code>, but provides more hooks
54 * for specialized subclass behavior. For general description,
55 * see {@link java.util.ListResourceBundle}.
56 * <p>
57 * This class leaves handleGetObject non-final, and
58 * adds a method createMap which allows subclasses to
59 * use specialized Map implementations.
60 */
61public abstract class OpenListResourceBundle extends ResourceBundle {
62    /**
63     * Sole constructor.  (For invocation by subclass constructors, typically
64     * implicit.)
65     */
66    protected OpenListResourceBundle() {
67    }
68
69    // Implements java.util.ResourceBundle.handleGetObject; inherits javadoc specification.
70    @Override
71    protected Object handleGetObject(String key) {
72        if (key == null) {
73            throw new NullPointerException();
74        }
75
76        loadLookupTablesIfNecessary();
77        return lookup.get(key); // this class ignores locales
78    }
79
80    /**
81     * Implementation of ResourceBundle.getKeys.
82     */
83    @Override
84    public Enumeration<String> getKeys() {
85        ResourceBundle parentBundle = this.parent;
86        return new ResourceBundleEnumeration(handleKeySet(),
87                (parentBundle != null) ? parentBundle.getKeys() : null);
88     }
89
90    /**
91     * Returns a set of keys provided in this resource bundle,
92     * including no parents.
93     */
94    @Override
95    protected Set<String> handleKeySet() {
96        loadLookupTablesIfNecessary();
97        return lookup.keySet();
98    }
99
100    @Override
101    public Set<String> keySet() {
102        if (keyset != null) {
103            return keyset;
104        }
105        Set<String> ks = createSet();
106        ks.addAll(handleKeySet());
107        if (parent != null) {
108            ks.addAll(parent.keySet());
109        }
110        synchronized (this) {
111            if (keyset == null) {
112                keyset = ks;
113            }
114        }
115        return keyset;
116    }
117
118    /**
119     * See ListResourceBundle class description.
120     */
121    protected abstract Object[][] getContents();
122
123    /**
124     * Load lookup tables if they haven't been loaded already.
125     */
126    void loadLookupTablesIfNecessary() {
127        if (lookup == null) {
128            loadLookup();
129        }
130    }
131
132    /**
133     * We lazily load the lookup hashtable.  This function does the
134     * loading.
135     */
136    private void loadLookup() {
137        Object[][] contents = getContents();
138        Map<String, Object> temp = createMap(contents.length);
139        for (int i = 0; i < contents.length; ++i) {
140            // key must be non-null String, value must be non-null
141            String key = (String) contents[i][0];
142            Object value = contents[i][1];
143            if (key == null || value == null) {
144                throw new NullPointerException();
145            }
146            temp.put(key, value);
147        }
148        synchronized (this) {
149            if (lookup == null) {
150                lookup = temp;
151            }
152        }
153    }
154
155    /**
156     * Lets subclasses provide specialized Map implementations.
157     * Default uses HashMap.
158     */
159    protected <K, V> Map<K, V> createMap(int size) {
160        return new HashMap<>(size);
161    }
162
163    protected <E> Set<E> createSet() {
164        return new HashSet<>();
165    }
166
167    private volatile Map<String, Object> lookup;
168    private volatile Set<String> keyset;
169}
170