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