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1: /* ButtonGroup.java -- 2: Copyright (C) 2002 Free Software Foundation, Inc. 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.swing; 39: 40: import java.io.Serializable; 41: import java.util.Enumeration; 42: import java.util.Vector; 43: 44: 45: /** 46: * Logically groups a set of buttons, so that only one of the buttons in 47: * a <code>ButtonGroup</code> can be selected at the same time. If one 48: * button in a <code>ButtonGroup</code> is selected, all other buttons 49: * are automatically deselected. 50: * 51: * While <code>ButtonGroup</code> can be used for all buttons that are derived 52: * from {@link AbstractButton}, it is normally only used for 53: * {@link JRadioButton}s, {@link JRadioButtonMenuItem}s and 54: * {@link JToggleButton}s. 55: * 56: * You could use it for {@link JCheckBox}es, but for the sake of usability 57: * this is strongly discouraged because the common expectation of checkboxes 58: * is that the user is allowed to make multiple selections. 59: * 60: * It makes no sense to put {@link JButton}s or {@link JMenuItem}s in 61: * a <code>ButtonGroup</code> because they don't implement the 62: * <code>selected</code> semantics. 63: * 64: * @author original author unknown 65: */ 66: public class ButtonGroup implements Serializable 67: { 68: /** DOCUMENT ME! */ 69: private static final long serialVersionUID = 4259076101881721375L; 70: 71: /** The buttons added to this button group. */ 72: protected Vector buttons = new Vector(); 73: 74: /** The currently selected button model. */ 75: ButtonModel sel; 76: 77: /** 78: * Creates a new button group. 79: */ 80: public ButtonGroup() 81: { 82: // Nothing to do here. 83: } 84: 85: /** 86: * Adds a button to this group. 87: * 88: * @param b the button to add 89: */ 90: public void add(AbstractButton b) 91: { 92: b.getModel().setGroup(this); 93: if (b.isSelected()) 94: sel = b.getModel(); 95: buttons.addElement(b); 96: } 97: 98: /** 99: * Removed a given button from this group. 100: * 101: * @param b the button to remove 102: */ 103: public void remove(AbstractButton b) 104: { 105: b.getModel().setGroup(null); 106: buttons.removeElement(b); 107: } 108: 109: /** 110: * Returns the currently added buttons. 111: * 112: * @return <code>Enumeration</code> over all added buttons 113: */ 114: public Enumeration getElements() 115: { 116: return buttons.elements(); 117: } 118: 119: /** 120: * Returns the currently selected button model. 121: * 122: * @return the currently selected button model, null if none was selected 123: * yet 124: */ 125: public ButtonModel getSelection() 126: { 127: return sel; 128: } 129: 130: /** 131: * DOCUMENT ME! 132: * 133: * @param m DOCUMENT ME! 134: * 135: * @return DOCUMENT ME! 136: */ 137: AbstractButton FindButton(ButtonModel m) 138: { 139: for (int i = 0; i < buttons.size(); i++) 140: { 141: AbstractButton a = (AbstractButton) buttons.get(i); 142: if (a.getModel() == m) 143: return a; 144: } 145: return null; 146: } 147: 148: /** 149: * Sets the currently selected button model. Only one button of a group can 150: * be selected at a time. 151: * 152: * @param m the model to select 153: * @param b true if this button is to be selected, false otherwise 154: */ 155: public void setSelected(ButtonModel m, boolean b) 156: { 157: if ((sel != m || b) && (! b || sel == m)) 158: return; 159: 160: if (b && sel != m) 161: { 162: ButtonModel old = sel; 163: sel = m; 164: 165: if (old != null) 166: old.setSelected(false); 167: AbstractButton button = FindButton(old); 168: if (button != null) 169: button.repaint(); 170: } 171: else if (!b && sel == m) 172: m.setSelected(true); 173: } 174: 175: /** 176: * Checks if the given <code>ButtonModel</code> is selected in this button 177: * group. 178: * 179: * @param m DOCUMENT ME! 180: * 181: * @return true of given <code>ButtonModel</code> is selected, false 182: * otherwise 183: */ 184: public boolean isSelected(ButtonModel m) 185: { 186: return m == sel; 187: } 188: 189: /** 190: * Return the number of buttons in this button group. 191: * 192: * @return the number of buttons 193: * 194: * @since 1.3 195: */ 196: public int getButtonCount() 197: { 198: return buttons.size(); 199: } 200: }
GNU Classpath (0.20) |