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1 /* |
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2 * Copyright 1995-2004 Sun Microsystems, Inc. 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. Sun designates this |
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8 * particular file as subject to the "Classpath" exception as provided |
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9 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
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22 * CA 95054 USA or visit www.sun.com if you need additional information or |
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23 * have any questions. |
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24 */ |
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25 package java.awt; |
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26 |
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27 /** |
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28 * The <code>CheckboxGroup</code> class is used to group together |
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29 * a set of <code>Checkbox</code> buttons. |
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30 * <p> |
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31 * Exactly one check box button in a <code>CheckboxGroup</code> can |
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32 * be in the "on" state at any given time. Pushing any |
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33 * button sets its state to "on" and forces any other button that |
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34 * is in the "on" state into the "off" state. |
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35 * <p> |
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36 * The following code example produces a new check box group, |
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37 * with three check boxes: |
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38 * <p> |
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39 * <hr><blockquote><pre> |
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40 * setLayout(new GridLayout(3, 1)); |
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41 * CheckboxGroup cbg = new CheckboxGroup(); |
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42 * add(new Checkbox("one", cbg, true)); |
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43 * add(new Checkbox("two", cbg, false)); |
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44 * add(new Checkbox("three", cbg, false)); |
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45 * </pre></blockquote><hr> |
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46 * <p> |
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47 * This image depicts the check box group created by this example: |
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48 * <p> |
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49 * <img src="doc-files/CheckboxGroup-1.gif" |
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50 * alt="Shows three checkboxes, arranged vertically, labeled one, two, and three. Checkbox one is in the on state." |
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51 * ALIGN=center HSPACE=10 VSPACE=7> |
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52 * <p> |
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53 * @author Sami Shaio |
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54 * @see java.awt.Checkbox |
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55 * @since JDK1.0 |
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56 */ |
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57 public class CheckboxGroup implements java.io.Serializable { |
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58 /** |
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59 * The current choice. |
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60 * @serial |
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61 * @see #getCurrent() |
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62 * @see #setCurrent(Checkbox) |
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63 */ |
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64 Checkbox selectedCheckbox = null; |
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65 |
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66 /* |
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67 * JDK 1.1 serialVersionUID |
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68 */ |
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69 private static final long serialVersionUID = 3729780091441768983L; |
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70 |
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71 /** |
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72 * Creates a new instance of <code>CheckboxGroup</code>. |
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73 */ |
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74 public CheckboxGroup() { |
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75 } |
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76 |
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77 /** |
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78 * Gets the current choice from this check box group. |
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79 * The current choice is the check box in this |
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80 * group that is currently in the "on" state, |
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81 * or <code>null</code> if all check boxes in the |
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82 * group are off. |
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83 * @return the check box that is currently in the |
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84 * "on" state, or <code>null</code>. |
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85 * @see java.awt.Checkbox |
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86 * @see java.awt.CheckboxGroup#setSelectedCheckbox |
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87 * @since JDK1.1 |
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88 */ |
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89 public Checkbox getSelectedCheckbox() { |
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90 return getCurrent(); |
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91 } |
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92 |
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93 /** |
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94 * @deprecated As of JDK version 1.1, |
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95 * replaced by <code>getSelectedCheckbox()</code>. |
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96 */ |
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97 @Deprecated |
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98 public Checkbox getCurrent() { |
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99 return selectedCheckbox; |
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100 } |
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101 |
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102 /** |
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103 * Sets the currently selected check box in this group |
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104 * to be the specified check box. |
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105 * This method sets the state of that check box to "on" and |
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106 * sets all other check boxes in the group to be off. |
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107 * <p> |
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108 * If the check box argument is <tt>null</tt>, all check boxes |
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109 * in this check box group are deselected. If the check box argument |
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110 * belongs to a different check box group, this method does |
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111 * nothing. |
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112 * @param box the <code>Checkbox</code> to set as the |
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113 * current selection. |
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114 * @see java.awt.Checkbox |
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115 * @see java.awt.CheckboxGroup#getSelectedCheckbox |
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116 * @since JDK1.1 |
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117 */ |
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118 public void setSelectedCheckbox(Checkbox box) { |
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119 setCurrent(box); |
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120 } |
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121 |
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122 /** |
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123 * @deprecated As of JDK version 1.1, |
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124 * replaced by <code>setSelectedCheckbox(Checkbox)</code>. |
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125 */ |
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126 @Deprecated |
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127 public synchronized void setCurrent(Checkbox box) { |
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128 if (box != null && box.group != this) { |
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129 return; |
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130 } |
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131 Checkbox oldChoice = this.selectedCheckbox; |
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132 this.selectedCheckbox = box; |
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133 if (oldChoice != null && oldChoice != box && oldChoice.group == this) { |
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134 oldChoice.setState(false); |
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135 } |
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136 if (box != null && oldChoice != box && !box.getState()) { |
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137 box.setStateInternal(true); |
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138 } |
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139 } |
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140 |
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141 /** |
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142 * Returns a string representation of this check box group, |
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143 * including the value of its current selection. |
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144 * @return a string representation of this check box group. |
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145 */ |
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146 public String toString() { |
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147 return getClass().getName() + "[selectedCheckbox=" + selectedCheckbox + "]"; |
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148 } |
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149 |
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150 } |