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