001    /* AccessibleStateSet.java -- the combined state of an accessible object
002       Copyright (C) 2002, 2005 Free Software Foundation
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    package javax.accessibility;
039    
040    import gnu.java.lang.CPStringBuilder;
041    
042    import java.util.Locale;
043    import java.util.Vector;
044    
045    /**
046     * Describes all elements of an accessible object's state. For example, an
047     * object may be enabled and have focus.
048     *
049     * @author Eric Blake (ebb9@email.byu.edu)
050     * @see AccessibleState
051     * @since 1.2
052     * @status updated to 1.4
053     */
054    public class AccessibleStateSet
055    {
056      /**
057       * The list of states, should be instances of AccessibleState. Don't set
058       * this to null.
059       *
060       * @see #add(AccessibleState)
061       * @see #addAll(AccessibleState[])
062       * @see #remove(AccessibleState)
063       * @see #contains(AccessibleState)
064       * @see #toArray()
065       * @see #clear()
066       */
067      protected Vector<AccessibleState> states = new Vector<AccessibleState>();
068    
069      /**
070       * Create an empty state set.
071       */
072      public AccessibleStateSet()
073      {
074      }
075    
076      /**
077       * Create a state set initialized with the given states, duplicates are
078       * ignored.
079       *
080       * @param states the states to insert
081       * @throws NullPointerException if states is null
082       */
083      public AccessibleStateSet(AccessibleState[] states)
084      {
085        addAll(states);
086      }
087    
088      /**
089       * Add a new state to the current set. Return true if the state was added,
090       * as duplicates are ignored. Entering a null state will cause problems
091       * later, so don't do it.
092       *
093       * @param state the state to add
094       * @return true if the state was added
095       */
096      public boolean add(AccessibleState state)
097      {
098        return states.contains(state) ? false : states.add(state);
099      }
100    
101      /**
102       * Add all of the states to the current set. Duplicates are ignored.
103       * Entering a null state will cause problems later, so don't do it.
104       *
105       * @param array the array of states to add
106       * @throws NullPointerException if array is null
107       */
108      public void addAll(AccessibleState[] array)
109      {
110        int i = array.length;
111        while (--i >= 0)
112          add(array[i]);
113      }
114    
115      /**
116       * Remove a state from the set. If a state was removed, return true.
117       *
118       * @param state the state to remove
119       * @return true if the set changed
120       */
121      public boolean remove(AccessibleState state)
122      {
123        return states.remove(state);
124      }
125    
126      /**
127       * Clear all states in the set.
128       */
129      public void clear()
130      {
131        states.clear();
132      }
133    
134      /**
135       * Check if the current state is in the set.
136       *
137       * @param state the state to locate
138       * @return true if it is in the set
139       */
140      public boolean contains(AccessibleState state)
141      {
142        return states.contains(state);
143      }
144    
145      /**
146       * Return the state set as an array.
147       *
148       * @return an array of the current states
149       */
150      public AccessibleState[] toArray()
151      {
152        AccessibleState[] result = new AccessibleState[states.size()];
153        states.toArray(result);
154        return result;
155      }
156    
157      /**
158       * Return a localized, comma-separated string representing all states
159       * in the set. This is in arbitrary order.
160       *
161       * @return the string representation
162       * @see AccessibleBundle#toDisplayString(String, Locale)
163       */
164      public String toString()
165      {
166        int i = states.size();
167        if (i == 0)
168          return "";
169        // Pre-allocate an average of 10 chars per state.
170        CPStringBuilder b = new CPStringBuilder(i * 10);
171        while (--i >= 0)
172          b.append(states.get(i)).append(',');
173        return b.substring(0, b.length() - 1);
174      }
175    } // class AccessibleStateSet