Source for javax.accessibility.AccessibleRelationSet

   1: /* AccessibleRelationSet.java -- the combined relations of an accessible object
   2:    Copyright (C) 2002, 2005 Free Software Foundation
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: package javax.accessibility;
  39: 
  40: import gnu.java.lang.CPStringBuilder;
  41: 
  42: import java.util.Locale;
  43: import java.util.Vector;
  44: 
  45: /**
  46:  * Describes all relations of an accessible object. For example, an object
  47:  * by labeled by one object and control another.
  48:  *
  49:  * @author Eric Blake (ebb9@email.byu.edu)
  50:  * @see AccessibleRelation
  51:  * @since 1.2
  52:  * @status updated to 1.4
  53:  */
  54: public class AccessibleRelationSet
  55: {
  56:   /**
  57:    * The list of relations, should be instances of AccessibleRelation. Don't
  58:    * set this to null.
  59:    *
  60:    * @see #add(AccessibleRelation)
  61:    * @see #addAll(AccessibleRelation[])
  62:    * @see #remove(AccessibleRelation)
  63:    * @see #contains(String)
  64:    * @see #get(String)
  65:    * @see #size()
  66:    * @see #toArray()
  67:    * @see #clear()
  68:    */
  69:   protected Vector<AccessibleRelation> relations
  70:     = new Vector<AccessibleRelation>();
  71: 
  72:   /**
  73:    * Create an empty relation set.
  74:    */
  75:   public AccessibleRelationSet()
  76:   {
  77:   }
  78: 
  79:   /**
  80:    * Create a relation set initialized with the given relations, duplicates are
  81:    * ignored.
  82:    *
  83:    * @param relations the relations to insert
  84:    * @throws NullPointerException if relations is null
  85:    */
  86:   public AccessibleRelationSet(AccessibleRelation[] relations)
  87:   {
  88:     addAll(relations);
  89:   }
  90: 
  91:   /**
  92:    * Add a new relation to the current set. If the relation is already in
  93:    * the set, the targets are merged with the existing relation, possibly
  94:    * resulting in an object being in the target list more than once. Do not
  95:    * add a relation with a null key, as it will cause problems later.
  96:    *
  97:    * @param relation the relation to add
  98:    * @return true if the set was modified, which is always the case
  99:    * @throws NullPointerException if relation is null
 100:    */
 101:   public boolean add(AccessibleRelation relation)
 102:   {
 103:     AccessibleRelation old = get(relation.key);
 104:     if (old == null)
 105:       return relations.add(relation);
 106:     if (old.targets.length == 0)
 107:       old.targets = relation.targets;
 108:     else if (relation.targets.length != 0)
 109:       {
 110:         Object[] t = new Object[old.targets.length + relation.targets.length];
 111:         System.arraycopy(old.targets, 0, t, 0, old.targets.length);
 112:         System.arraycopy(relation.targets, 0, t, old.targets.length,
 113:                          relation.targets.length);
 114:         old.targets = t;
 115:       }
 116:     return true;
 117:   }
 118: 
 119:   /**
 120:    * Add all of the relations to the current set. Duplicates are ignored.
 121:    *
 122:    * @param array the array of relations to add
 123:    * @throws NullPointerException if array is null or has null entries
 124:    */
 125:   public void addAll(AccessibleRelation[] array)
 126:   {
 127:     int i = array.length;
 128:     while (--i >= 0)
 129:       add(array[i]);
 130:   }
 131: 
 132:   /**
 133:    * Remove a relation from the set. If a relation was removed, return true.
 134:    * Note that this uses AccessibleRelation.equals, which defaults to ==, so a
 135:    * relation with the same key may still exist in the set afterwords.
 136:    *
 137:    * @param relation the state to remove
 138:    * @return true if the set changed
 139:    */
 140:   public boolean remove(AccessibleRelation relation)
 141:   {
 142:     return relations.remove(relation);
 143:   }
 144: 
 145:   /**
 146:    * Clear all relations in the set.
 147:    */
 148:   public void clear()
 149:   {
 150:     relations.clear();
 151:   }
 152: 
 153:   /**
 154:    * Return the number of relations in the set.
 155:    *
 156:    * @return the set size
 157:    */
 158:   public int size()
 159:   {
 160:     return relations.size();
 161:   }
 162: 
 163:   /**
 164:    * Check if the relation key is in the set.
 165:    *
 166:    * @param key the relation to locate
 167:    * @return true if it is in the set
 168:    */
 169:   public boolean contains(String key)
 170:   {
 171:     int i = relations.size();
 172:     while (--i >= 0)
 173:       if ((relations.get(i)).key.equals(key))
 174:         return true;
 175:     return false;
 176:   }
 177: 
 178:   /**
 179:    * Get the relation that matches the key.
 180:    *
 181:    * @param key the relation to locate
 182:    * @return the relation in the set, or null
 183:    */
 184:   public AccessibleRelation get(String key)
 185:   {
 186:     int i = relations.size();
 187:     while (--i >= 0)
 188:       {
 189:         AccessibleRelation r = relations.get(i);
 190:         if (r.key.equals(key))
 191:           return r;
 192:       }
 193:     return null;
 194:   }
 195: 
 196:   /**
 197:    * Return the relation set as an array.
 198:    *
 199:    * @return an array of the current relations
 200:    */
 201:   public AccessibleRelation[] toArray()
 202:   {
 203:     AccessibleRelation[] result = new AccessibleRelation[relations.size()];
 204:     relations.toArray(result);
 205:     return result;
 206:   }
 207: 
 208:   /**
 209:    * Return a localized, comma-separated string representing all relations
 210:    * in the set. This is in arbitrary order.
 211:    *
 212:    * @return the string representation
 213:    * @see AccessibleBundle#toDisplayString(String, Locale)
 214:    */
 215:   public String toString()
 216:   {
 217:     int i = relations.size();
 218:     if (i == 0)
 219:       return "";
 220:     // Pre-allocate an average of 10 chars per state.
 221:     CPStringBuilder b = new CPStringBuilder(i * 10);
 222:     while (--i >= 0)
 223:       b.append(relations.get(i)).append(',');
 224:     return b.substring(0, b.length() - 1);
 225:   }
 226: } // class AccessibleRelationSet