001 /* PropertyResourceBundle -- a resource bundle built from a Property file
002 Copyright (C) 1998, 1999, 2001, 2002 Free Software Foundation, Inc.
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
011 GNU Classpath is distributed in the hope that it will be useful, but
012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
016 You should have received a copy of the GNU General Public License
017 along with GNU Classpath; see the file COPYING. If not, write to the
018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
032 module. An independent module is a module which is not derived from
033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038
039 package java.util;
040
041 import java.io.IOException;
042 import java.io.InputStream;
043
044 /**
045 * This class is a concrete <code>ResourceBundle</code> that gets it
046 * resources from a property file. This implies that the resources are
047 * strings. For more information about resource bundles see the class
048 * <code>ResourceBundle</code>.
049 *
050 * You should not use this class directly, or subclass it, but you get
051 * an object of this class automatically when you call
052 * <code>ResourceBundle.getBundle()</code> and there is a properties
053 * file.
054 *
055 * If there is also a class for this resource and the same locale, the
056 * class will be chosen. The properties file should have the name of the
057 * resource bundle, appended with the locale (e.g. <code>_de</code> and the
058 * extension <code>.properties</code>. The file should have the same format
059 * as for <code>Properties.load()</code>
060 *
061 * An example of a properties file for the german language is given
062 * here. This extends the example given in ListResourceBundle.
063 * Create a file MyResource_de.properties with the following contents
064 * and put it in the CLASSPATH. (The char <code>\u00e4</code> is the
065 * german umlaut)
066 *
067 *
068 <pre>
069 s1=3
070 s2=MeineDisk
071 s3=3. M\u00e4rz 96
072 s4=Die Diskette ''{1}'' enth\u00e4lt {0} in {2}.
073 s5=0
074 s6=keine Dateien
075 s7=1
076 s8=eine Datei
077 s9=2
078 s10={0,number} Dateien
079 s11=Die Formatierung warf eine Exception: {0}
080 s12=FEHLER
081 s13=Ergebnis
082 s14=Dialog
083 s15=Auswahlkriterium
084 s16=1,3
085 </pre>
086 *
087 * @author Jochen Hoenicke
088 * @see ResourceBundle
089 * @see ListResourceBundle
090 * @see Properties#load(InputStream)
091 * @since 1.1
092 * @status updated to 1.4
093 */
094 public class PropertyResourceBundle extends ResourceBundle
095 {
096 /** The properties file this bundle is based on. */
097 private Properties properties;
098
099 /**
100 * Creates a new property resource bundle.
101 *
102 * @param stream an input stream, where the resources are read from
103 * @throws NullPointerException if stream is null
104 * @throws IOException if reading the stream fails
105 */
106 public PropertyResourceBundle(InputStream stream) throws IOException
107 {
108 properties = new Properties();
109 properties.load(stream);
110 }
111
112 /**
113 * Called by <code>getObject</code> when a resource is needed. This
114 * returns the resource given by the key.
115 *
116 * @param key the key of the resource
117 * @return the resource for the key, or null if it doesn't exist
118 */
119 public Object handleGetObject(String key)
120 {
121 return properties.getProperty(key);
122 }
123
124 /**
125 * This method should return all keys for which a resource exists.
126 *
127 * @return an enumeration of the keys
128 */
129 public Enumeration<String> getKeys()
130 {
131 if (parent == null)
132 // FIXME: bogus cast.
133 return (Enumeration<String>) properties.propertyNames();
134 // We make a new Set that holds all the keys, then return an enumeration
135 // for that. This prevents modifications from ruining the enumeration,
136 // as well as ignoring duplicates.
137 Set<String> s = new HashSet<String>();
138 // FIXME: bogus cast.
139 Enumeration<String> e = (Enumeration<String>) properties.propertyNames();
140 while (e.hasMoreElements())
141 s.add(e.nextElement());
142 ResourceBundle bundle = parent;
143 // Eliminate tail recursion.
144 do
145 {
146 e = bundle.getKeys();
147 while (e.hasMoreElements())
148 s.add(e.nextElement());
149 bundle = bundle.parent;
150 }
151 while (bundle != null);
152 return Collections.enumeration(s);
153 }
154 } // class PropertyResourceBundle