001: /*
002: * @(#)CheckboxGroup.java 1.10 06/10/10
003: *
004: * Copyright 1990-2006 Sun Microsystems, Inc. All Rights Reserved.
005: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
006: *
007: * This program is free software; you can redistribute it and/or
008: * modify it under the terms of the GNU General Public License version
009: * 2 only, as published by the Free Software Foundation.
010: *
011: * This program 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 version 2 for more details (a copy is
015: * included at /legal/license.txt).
016: *
017: * You should have received a copy of the GNU General Public License
018: * version 2 along with this work; if not, write to the Free Software
019: * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
020: * 02110-1301 USA
021: *
022: * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
023: * Clara, CA 95054 or visit www.sun.com if you need additional
024: * information or have any questions.
025: *
026: */
027: package java.awt;
028:
029: import javax.swing.ButtonGroup;
030:
031: /**
032: * The <code>CheckboxGroup</code> class is used to group together
033: * a set of <code>Checkbox</code> buttons.
034: * <p>
035: * Exactly one check box button in a <code>CheckboxGroup</code> can
036: * be in the "on" state at any given time. Pushing any
037: * button sets its state to "on" and forces any other button that
038: * is in the "on" state into the "off" state.
039: * <p>
040: * The following code example produces a new check box group,
041: * with three check boxes:
042: * <p>
043: * <hr><blockquote><pre>
044: * setLayout(new GridLayout(3, 1));
045: * CheckboxGroup cbg = new CheckboxGroup();
046: * add(new Checkbox("one", cbg, true));
047: * add(new Checkbox("two", cbg, false));
048: * add(new Checkbox("three", cbg, false));
049: * </pre></blockquote><hr>
050: * <p>
051: * This image depicts the check box group created by this example:
052: * <p>
053: * <img src="images-awt/CheckboxGroup-1.gif"
054: * ALIGN=center HSPACE=10 VSPACE=7>
055: * <p>
056: * @version 1.6, 08/19/02
057: * @author Nicholas Allen
058: * @see java.awt.Checkbox
059: * @since JDK1.0
060: */
061: public class CheckboxGroup implements java.io.Serializable {
062: /**
063: * The current choice.
064: */
065: Checkbox selectedCheckbox = null;
066: /*
067: * JDK 1.1 serialVersionUID
068: */
069: private static final long serialVersionUID = 3729780091441768983L;
070:
071: /**
072: * Creates a new instance of <code>CheckboxGroup</code>.
073: * @since JDK1.0
074: */
075: public CheckboxGroup() {
076: }
077:
078: /**
079: * Gets the current choice from this check box group.
080: * The current choice is the check box in this
081: * group that is currently in the "on" state,
082: * or <code>null</code> if all check boxes in the
083: * group are off.
084: * @return the check box that is currently in the
085: * "on" state, or <code>null</code>.
086: * @see java.awt.Checkbox
087: * @see java.awt.CheckboxGroup#setSelectedCheckbox
088: * @since JDK1.1
089: */
090: public Checkbox getSelectedCheckbox() {
091: return getCurrent();
092: }
093:
094: /**
095: * @deprecated As of JDK version 1.1,
096: * replaced by <code>getSelectedCheckbox()</code>.
097: */
098: public Checkbox getCurrent() {
099: return selectedCheckbox;
100: }
101:
102: /**
103: * Sets the currently selected check box in this group
104: * to be the specified check box.
105: * This method sets the state of that check box to "on" and
106: * sets all other check boxes in the group to be off.
107: * <p>
108: * If the check box argument is <code>null</code> or belongs to a
109: * different check box group, then this method does nothing.
110: * @param box the <code>Checkbox</code> to set as the
111: * current selection.
112: * @see java.awt.Checkbox
113: * @see java.awt.CheckboxGroup#getSelectedCheckbox
114: * @since JDK1.1
115: */
116: public void setSelectedCheckbox(Checkbox box) {
117: setCurrent(box);
118: }
119:
120: /**
121: * @deprecated As of JDK version 1.1,
122: * replaced by <code>setSelectedCheckbox(Checkbox)</code>.
123: */
124: public synchronized void setCurrent(Checkbox box) {
125: if (box != null && box.group != this ) {
126: return;
127: }
128: Checkbox oldChoice = this .selectedCheckbox;
129: this .selectedCheckbox = box;
130: if ((oldChoice != null) && (oldChoice != box)) {
131: oldChoice.setState(false);
132: }
133: if (box != null && oldChoice != box && !box.getState()) {
134: box.setStateInternal(true);
135: }
136: }
137:
138: /**
139: * Returns a string representation of this check box group,
140: * including the value of its current selection.
141: * @return a string representation of this check box group.
142: * @since JDK1.0
143: */
144: public String toString() {
145: return getClass().getName() + "[selectedCheckbox="
146: + selectedCheckbox + "]";
147: }
148: }
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