1 /*

     2  * Portions Copyright 2005-2007 Sun Microsystems, Inc.  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.  Sun designates this

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

     9  * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

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

    23  * have any 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 }