001/* ListResourceBundle -- a resource bundle build around a list
002   Copyright (C) 1998, 1999, 2001, 2002, 2005  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
041/**
042 * A <code>ListResouceBundle</code> provides an easy way, to create your own
043 * resource bundle. It is an abstract class that you can subclass. You should
044 * then overwrite the getContents method, that provides a key/value list.
045 *
046 * <p>The key/value list is a two dimensional list of Object.  The first
047 * dimension ranges over the resources. The second dimension ranges from
048 * zero (key) to one (value). The keys must be of type String, and they are
049 * case-sensitive. For example:
050 *
051<br><pre>public class MyResources
052  extends ListResourceBundle
053{
054  public Object[][] getContents()
055  {
056    return contents;
057  }
058
059  static final Object[][] contents =
060  {
061    // LOCALIZED STRINGS
062    {"s1", "The disk \"{1}\" contains {0}."},  // MessageFormat pattern
063    {"s2", "1"},                       // location of {0} in pattern
064    {"s3", "My Disk"},                 // sample disk name
065    {"s4", "no files"},                // first ChoiceFormat choice
066    {"s5", "one file"},                // second ChoiceFormat choice
067    {"s6", "{0,number} files"}         // third ChoiceFormat choice
068    {"s7", "3 Mar 96"},                // sample date
069    {"s8", new Dimension(1,5)}         // real object, not just string
070    // END OF LOCALIZED MATERIAL
071  };
072}</pre>
073 *
074 * @author Jochen Hoenicke
075 * @author Eric Blake (ebb9@email.byu.edu)
076 * @see Locale
077 * @see PropertyResourceBundle
078 * @since 1.1
079 * @status updated to 1.4
080 */
081public abstract class ListResourceBundle extends ResourceBundle
082{
083  /**
084   * The constructor. It does nothing special.
085   */
086  public ListResourceBundle()
087  {
088  }
089
090  /**
091   * Gets a resource for a given key. This is called by <code>getObject</code>.
092   *
093   * @param key the key of the resource
094   * @return the resource for the key, or null if it doesn't exist
095   */
096  public final Object handleGetObject(String key)
097  {
098    Object[][] contents = getContents();
099    int i = contents.length;
100    while (--i >= 0)
101      if (key.equals(contents[i][0]))
102        return contents[i][1];
103    return null;
104  }
105
106  /**
107   * This method should return all keys for which a resource exists.
108   *
109   * @return an enumeration of the keys
110   */
111  public Enumeration<String> getKeys()
112  {
113    // We make a new Set that holds all the keys, then return an enumeration
114    // for that. This prevents modifications from ruining the enumeration,
115    // as well as ignoring duplicates.
116    final Object[][] contents = getContents();
117    Set<String> s = new HashSet<String>();
118    int i = contents.length;
119    while (--i >= 0)
120      s.add((String) contents[i][0]);
121    ResourceBundle bundle = parent;
122    // Eliminate tail recursion.
123    while (bundle != null)
124      {
125        Enumeration<String> e = bundle.getKeys();
126        while (e.hasMoreElements())
127          s.add(e.nextElement());
128        bundle = bundle.parent;
129      }
130    return Collections.enumeration(s);
131  }
132
133  /**
134   * Gets the key/value list. You must override this method, and should not
135   * provide duplicate keys or null entries.
136   *
137   * @return a two dimensional list of String key / Object resouce pairs
138   */
139  protected abstract Object[][] getContents();
140} // class ListResourceBundle