001/* AccessibleRelationSet.java -- the combined relations of an accessible object 002 Copyright (C) 2002, 2005 Free Software Foundation 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 038package javax.accessibility; 039 040import gnu.java.lang.CPStringBuilder; 041 042import java.util.Locale; 043import java.util.Vector; 044 045/** 046 * Describes all relations of an accessible object. For example, an object 047 * by labeled by one object and control another. 048 * 049 * @author Eric Blake (ebb9@email.byu.edu) 050 * @see AccessibleRelation 051 * @since 1.2 052 * @status updated to 1.4 053 */ 054public class AccessibleRelationSet 055{ 056 /** 057 * The list of relations, should be instances of AccessibleRelation. Don't 058 * set this to null. 059 * 060 * @see #add(AccessibleRelation) 061 * @see #addAll(AccessibleRelation[]) 062 * @see #remove(AccessibleRelation) 063 * @see #contains(String) 064 * @see #get(String) 065 * @see #size() 066 * @see #toArray() 067 * @see #clear() 068 */ 069 protected Vector<AccessibleRelation> relations 070 = new Vector<AccessibleRelation>(); 071 072 /** 073 * Create an empty relation set. 074 */ 075 public AccessibleRelationSet() 076 { 077 } 078 079 /** 080 * Create a relation set initialized with the given relations, duplicates are 081 * ignored. 082 * 083 * @param relations the relations to insert 084 * @throws NullPointerException if relations is null 085 */ 086 public AccessibleRelationSet(AccessibleRelation[] relations) 087 { 088 addAll(relations); 089 } 090 091 /** 092 * Add a new relation to the current set. If the relation is already in 093 * the set, the targets are merged with the existing relation, possibly 094 * resulting in an object being in the target list more than once. Do not 095 * add a relation with a null key, as it will cause problems later. 096 * 097 * @param relation the relation to add 098 * @return true if the set was modified, which is always the case 099 * @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