001/* PropertyResourceBundle -- a resource bundle built from a Property file
002   Copyright (C) 1998, 1999, 2001, 2002 Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package java.util;
040
041import java.io.IOException;
042import java.io.InputStream;
043import java.io.Reader;
044
045/**
046 * This class is a concrete <code>ResourceBundle</code> that gets it
047 * resources from a property file. This implies that the resources are
048 * strings. For more information about resource bundles see the class
049 * <code>ResourceBundle</code>.
050 *
051 * You should not use this class directly, or subclass it, but you get
052 * an object of this class automatically when you call
053 * <code>ResourceBundle.getBundle()</code> and there is a properties
054 * file.
055 *
056 * If there is also a class for this resource and the same locale, the
057 * class will be chosen. The properties file should have the name of the
058 * resource bundle, appended with the locale (e.g. <code>_de</code> and the
059 * extension <code>.properties</code>. The file should have the same format
060 * as for <code>Properties.load()</code>
061 *
062 * An example of a properties file for the german language is given
063 * here. This extends the example given in ListResourceBundle.
064 * Create a file MyResource_de.properties with the following contents
065 * and put it in the CLASSPATH. (The char <code>\u00e4</code> is the
066 * german umlaut)
067 *
068 *
069<pre>
070s1=3
071s2=MeineDisk
072s3=3. M\u00e4rz 96
073s4=Die Diskette ''{1}'' enth\u00e4lt {0} in {2}.
074s5=0
075s6=keine Dateien
076s7=1
077s8=eine Datei
078s9=2
079s10={0,number} Dateien
080s11=Die Formatierung warf eine Exception: {0}
081s12=FEHLER
082s13=Ergebnis
083s14=Dialog
084s15=Auswahlkriterium
085s16=1,3
086</pre>
087 *
088 * @author Jochen Hoenicke
089 * @see ResourceBundle
090 * @see ListResourceBundle
091 * @see Properties#load(InputStream)
092 * @since 1.1
093 * @status updated to 1.4
094 */
095public class PropertyResourceBundle extends ResourceBundle
096{
097  /** The properties file this bundle is based on. */
098  private Properties properties;
099
100  /**
101   * Creates a new property resource bundle.  The property file must
102   * be encoded using ISO-8859-1.
103   *
104   * @param stream an input stream, where the resources are read from
105   * @throws NullPointerException if stream is null
106   * @throws IOException if reading the stream fails
107   */
108  public PropertyResourceBundle(InputStream stream) throws IOException
109  {
110    properties = new Properties();
111    properties.load(stream);
112  }
113
114  /**
115   * Creates a new property resource bundle.  The encoding of the property
116   * file is determined by the supplied {@link Reader} object.
117   *
118   * @param reader an input stream, where the resources are read from
119   * @throws NullPointerException if stream is null
120   * @throws IOException if reading the stream fails
121   * @since 1.6
122   */
123  public PropertyResourceBundle(Reader reader) throws IOException
124  {
125    properties = new Properties();
126    properties.load(reader);
127  }
128
129  /**
130   * Called by <code>getObject</code> when a resource is needed. This
131   * returns the resource given by the key.
132   *
133   * @param key the key of the resource
134   * @return the resource for the key, or null if it doesn't exist
135   */
136  public Object handleGetObject(String key)
137  {
138    return properties.getProperty(key);
139  }
140
141  /**
142   * This method should return all keys for which a resource exists.
143   *
144   * @return an enumeration of the keys
145   */
146  public Enumeration<String> getKeys()
147  {
148    if (parent == null)
149      // FIXME: bogus cast.
150      return (Enumeration<String>) properties.propertyNames();
151    // We make a new Set that holds all the keys, then return an enumeration
152    // for that. This prevents modifications from ruining the enumeration,
153    // as well as ignoring duplicates.
154    Set<String> s = new HashSet<String>();
155    // FIXME: bogus cast.
156    Enumeration<String> e = (Enumeration<String>) properties.propertyNames();
157    while (e.hasMoreElements())
158      s.add(e.nextElement());
159    ResourceBundle bundle = parent;
160    // Eliminate tail recursion.
161    do
162      {
163        e = bundle.getKeys();
164        while (e.hasMoreElements())
165          s.add(e.nextElement());
166        bundle = bundle.parent;
167      }
168    while (bundle != null);
169    return Collections.enumeration(s);
170  }
171} // class PropertyResourceBundle