1   /*
2    * Copyright (c) 2005, 2007, 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  
41  package sun.util.resources;
42  
43  import java.util.Enumeration;
44  import java.util.HashMap;
45  import java.util.Map;
46  import java.util.ResourceBundle;
47  import java.util.Set;
48  import sun.util.ResourceBundleEnumeration;
49  
50  /**
51   * Subclass of <code>ResourceBundle</code> which mimics
52   * <code>ListResourceBundle</code>, but provides more hooks
53   * for specialized subclass behavior. For general description,
54   * see {@link java.util.ListResourceBundle}.
55   * <p>
56   * This class leaves handleGetObject non-final, and
57   * adds a method createMap which allows subclasses to
58   * use specialized Map implementations.
59   */
60  public abstract class OpenListResourceBundle extends ResourceBundle {
61      /**
62       * Sole constructor.  (For invocation by subclass constructors, typically
63       * implicit.)
64       */
65      protected OpenListResourceBundle() {
66      }
67  
68      // Implements java.util.ResourceBundle.handleGetObject; inherits javadoc specification.
69      public Object handleGetObject(String key) {
70          if (key == null) {
71              throw new NullPointerException();
72          }
73  
74          loadLookupTablesIfNecessary();
75          return lookup.get(key); // this class ignores locales
76      }
77  
78      /**
79       * Implementation of ResourceBundle.getKeys.
80       */
81      public Enumeration<String> getKeys() {
82          ResourceBundle parent = this.parent;
83          return new ResourceBundleEnumeration(handleGetKeys(),
84                  (parent != null) ? parent.getKeys() : null);
85      }
86  
87      /**
88       * Returns a set of keys provided in this resource bundle
89       */
90      public Set<String> handleGetKeys() {
91          loadLookupTablesIfNecessary();
92  
93          return lookup.keySet();
94      }
95  
96      /**
97       * Returns the parent bundle
98       */
99      public OpenListResourceBundle getParent() {
100         return (OpenListResourceBundle)parent;
101     }
102 
103     /**
104      * See ListResourceBundle class description.
105      */
106     abstract protected Object[][] getContents();
107 
108     /**
109      * Load lookup tables if they haven't been loaded already.
110      */
111     void loadLookupTablesIfNecessary() {
112         if (lookup == null) {
113             loadLookup();
114         }
115     }
116 
117     /**
118      * We lazily load the lookup hashtable.  This function does the
119      * loading.
120      */
121     private synchronized void loadLookup() {
122         if (lookup != null)
123             return;
124 
125         Object[][] contents = getContents();
126         Map temp = createMap(contents.length);
127         for (int i = 0; i < contents.length; ++i) {
128             // key must be non-null String, value must be non-null
129             String key = (String) contents[i][0];
130             Object value = contents[i][1];
131             if (key == null || value == null) {
132                 throw new NullPointerException();
133             }
134             temp.put(key, value);
135         }
136         lookup = temp;
137     }
138 
139     /**
140      * Lets subclasses provide specialized Map implementations.
141      * Default uses HashMap.
142      */
143     protected Map createMap(int size) {
144         return new HashMap(size);
145     }
146 
147     private Map lookup = null;
148 }