1 /* |
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2 * Copyright (c) 2002, 2016, Oracle and/or its affiliates. All rights reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. Oracle designates this |
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8 * particular file as subject to the "Classpath" exception as provided |
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9 * by Oracle in the LICENSE file that accompanied this code. |
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10 * |
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11 * This code is distributed in the hope that it will be useful, but WITHOUT |
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12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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14 * version 2 for more details (a copy is included in the LICENSE file that |
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15 * accompanied this code). |
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16 * |
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17 * You should have received a copy of the GNU General Public License version |
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18 * 2 along with this work; if not, write to the Free Software Foundation, |
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19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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20 * |
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21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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22 * or visit www.oracle.com if you need additional information or have any |
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23 * questions. |
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24 */ |
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25 |
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26 package sun.lwawt.macosx; |
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27 |
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28 import java.beans.PropertyChangeEvent; |
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29 import java.beans.PropertyChangeListener; |
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30 import javax.accessibility.Accessible; |
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31 import javax.accessibility.AccessibleContext; |
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32 import javax.accessibility.AccessibleRole; |
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33 import javax.accessibility.AccessibleState; |
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34 import javax.accessibility.AccessibleStateSet; |
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35 import javax.swing.event.EventListenerList; |
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36 |
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37 /** |
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38 * <P>{@code AccessibilityEventMonitor} implements a PropertyChange listener |
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39 * on every UI object that implements interface {@code Accessible} in the Java |
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40 * Virtual Machine. The events captured by these listeners are made available |
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41 * through listeners supported by {@code AccessibilityEventMonitor}. |
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42 * With this, all the individual events on each of the UI object |
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43 * instances are funneled into one set of PropertyChange listeners. |
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44 * |
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45 * This code is a subset of com.sun.java.accessibility.util.AccessibilityEventMonitor |
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46 * which resides in module jdk.accessibility. Due to modularization the code in |
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47 * this package, java.desktop, can not be dependent on code in jdk.accessibility. |
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48 */ |
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49 |
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50 class AccessibilityEventMonitor { |
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51 |
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52 /** |
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53 * The current list of registered {@link java.beans.PropertyChangeListener |
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54 * PropertyChangeListener} classes. |
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55 * |
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56 * @see #addPropertyChangeListener |
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57 */ |
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58 private static final EventListenerList listenerList = |
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59 new EventListenerList(); |
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60 |
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61 |
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62 /** |
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63 * The actual listener that is installed on the component instances. |
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64 * This listener calls the other registered listeners when an event |
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65 * occurs. By doing things this way, the actual number of listeners |
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66 * installed on a component instance is drastically reduced. |
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67 */ |
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68 private static final AccessibilityEventListener accessibilityListener = |
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69 new AccessibilityEventListener(); |
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70 |
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71 /** |
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72 * Adds the specified listener to receive all PropertyChange events on |
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73 * each UI object instance in the Java Virtual Machine as they occur. |
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74 * <P>Note: This listener is automatically added to all component |
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75 * instances created after this method is called. In addition, it |
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76 * is only added to UI object instances that support this listener type. |
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77 * |
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78 * @param l the listener to add |
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79 * @param a the Accessible object to add the PropertyChangeListener to |
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80 */ |
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81 |
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82 static void addPropertyChangeListener(PropertyChangeListener l, Accessible a) { |
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83 if (listenerList.getListenerCount(PropertyChangeListener.class) == 0) { |
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84 accessibilityListener.installListeners(a); |
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85 } |
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86 listenerList.add(PropertyChangeListener.class, l); |
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87 } |
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88 |
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89 /** |
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90 * AccessibilityEventListener is the class that does all the work for |
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91 * AccessibilityEventMonitor. It is not intended for use by any other |
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92 * class except AccessibilityEventMonitor. |
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93 */ |
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94 |
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95 private static class AccessibilityEventListener implements PropertyChangeListener { |
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96 |
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97 /** |
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98 * Installs PropertyChange listeners to the Accessible object, and its |
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99 * children (so long as the object isn't of TRANSIENT state). |
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100 * |
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101 * @param a the Accessible object to add listeners to |
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102 */ |
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103 private void installListeners(Accessible a) { |
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104 installListeners(a.getAccessibleContext()); |
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105 } |
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106 |
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107 /** |
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108 * Installs PropertyChange listeners to the AccessibleContext object, |
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109 * and its * children (so long as the object isn't of TRANSIENT state). |
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110 * |
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111 * @param ac the AccessibleContext to add listeners to |
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112 */ |
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113 private void installListeners(AccessibleContext ac) { |
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114 |
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115 if (ac != null) { |
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116 AccessibleStateSet states = ac.getAccessibleStateSet(); |
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117 if (!states.contains(AccessibleState.TRANSIENT)) { |
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118 ac.addPropertyChangeListener(this); |
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119 /* |
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120 * Don't add listeners to transient children. Components |
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121 * with transient children should return an AccessibleStateSet |
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122 * containing AccessibleState.MANAGES_DESCENDANTS. Components |
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123 * may not explicitly return the MANAGES_DESCENDANTS state. |
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124 * In this case, don't add listeners to the children of |
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125 * lists, tables and trees. |
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126 */ |
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127 AccessibleStateSet set = ac.getAccessibleStateSet(); |
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128 if (set.contains(AccessibleState.MANAGES_DESCENDANTS)) { |
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129 return; |
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130 } |
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131 AccessibleRole role = ac.getAccessibleRole(); |
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132 if ( role == AccessibleRole.LIST || |
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133 role == AccessibleRole.TREE ) { |
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134 return; |
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135 } |
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136 if (role == AccessibleRole.TABLE) { |
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137 // handle Oracle tables containing tables |
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138 Accessible child = ac.getAccessibleChild(0); |
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139 if (child != null) { |
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140 AccessibleContext ac2 = child.getAccessibleContext(); |
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141 if (ac2 != null) { |
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142 role = ac2.getAccessibleRole(); |
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143 if (role != null && role != AccessibleRole.TABLE) { |
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144 return; |
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145 } |
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146 } |
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147 } |
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148 } |
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149 int count = ac.getAccessibleChildrenCount(); |
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150 for (int i = 0; i < count; i++) { |
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151 Accessible child = ac.getAccessibleChild(i); |
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152 if (child != null) { |
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153 installListeners(child); |
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154 } |
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155 } |
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156 } |
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157 } |
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158 } |
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159 |
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160 /** |
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161 * Removes PropertyChange listeners for the given Accessible object, |
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162 * its children (so long as the object isn't of TRANSIENT state). |
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163 * |
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164 * @param a the Accessible object to remove listeners from |
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165 */ |
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166 private void removeListeners(Accessible a) { |
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167 removeListeners(a.getAccessibleContext()); |
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168 } |
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169 |
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170 /** |
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171 * Removes PropertyChange listeners for the given AccessibleContext |
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172 * object, its children (so long as the object isn't of TRANSIENT |
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173 * state). |
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174 * |
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175 * @param a the Accessible object to remove listeners from |
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176 */ |
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177 private void removeListeners(AccessibleContext ac) { |
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178 |
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179 if (ac != null) { |
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180 // Listeners are not added to transient components. |
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181 AccessibleStateSet states = ac.getAccessibleStateSet(); |
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182 if (!states.contains(AccessibleState.TRANSIENT)) { |
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183 ac.removePropertyChangeListener(this); |
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184 /* |
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185 * Listeners are not added to transient children. Components |
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186 * with transient children should return an AccessibleStateSet |
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187 * containing AccessibleState.MANAGES_DESCENDANTS. Components |
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188 * may not explicitly return the MANAGES_DESCENDANTS state. |
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189 * In this case, don't remove listeners from the children of |
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190 * lists, tables and trees. |
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191 */ |
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192 if (states.contains(AccessibleState.MANAGES_DESCENDANTS)) { |
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193 return; |
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194 } |
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195 AccessibleRole role = ac.getAccessibleRole(); |
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196 if ( role == AccessibleRole.LIST || |
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197 role == AccessibleRole.TABLE || |
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198 role == AccessibleRole.TREE ) { |
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199 return; |
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200 } |
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201 int count = ac.getAccessibleChildrenCount(); |
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202 for (int i = 0; i < count; i++) { |
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203 Accessible child = ac.getAccessibleChild(i); |
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204 if (child != null) { |
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205 removeListeners(child); |
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206 } |
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207 } |
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208 } |
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209 } |
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210 } |
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211 |
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212 @Override |
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213 public void propertyChange(PropertyChangeEvent e) { |
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214 // propogate the event |
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215 Object[] listeners = |
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216 AccessibilityEventMonitor.listenerList.getListenerList(); |
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217 for (int i = listeners.length-2; i>=0; i-=2) { |
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218 if (listeners[i]==PropertyChangeListener.class) { |
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219 ((PropertyChangeListener)listeners[i+1]).propertyChange(e); |
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220 } |
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221 } |
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222 |
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223 // handle childbirth/death |
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224 String name = e.getPropertyName(); |
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225 if (name.compareTo(AccessibleContext.ACCESSIBLE_CHILD_PROPERTY) == 0) { |
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226 Object oldValue = e.getOldValue(); |
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227 Object newValue = e.getNewValue(); |
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228 |
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229 if ((oldValue == null) ^ (newValue == null)) { // one null, not both |
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230 if (oldValue != null) { |
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231 // this Accessible is a child that's going away |
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232 if (oldValue instanceof Accessible) { |
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233 Accessible a = (Accessible) oldValue; |
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234 removeListeners(a.getAccessibleContext()); |
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235 } else if (oldValue instanceof AccessibleContext) { |
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236 removeListeners((AccessibleContext) oldValue); |
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237 } |
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238 } else if (newValue != null) { |
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239 // this Accessible is a child was just born |
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240 if (newValue instanceof Accessible) { |
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241 Accessible a = (Accessible) newValue; |
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242 installListeners(a.getAccessibleContext()); |
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243 } else if (newValue instanceof AccessibleContext) { |
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244 installListeners((AccessibleContext) newValue); |
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245 } |
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246 } |
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247 } else { |
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248 System.out.println("ERROR in usage of PropertyChangeEvents for: " + e.toString()); |
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249 } |
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250 } |
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251 } |
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252 } |
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253 } |
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