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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: } 83: 84: /** 85: * Adds a button to this group. 86: * 87: * @param b the button to add 88: */ 89: public void add(AbstractButton b) 90: { 91: b.getModel().setGroup(this); 92: buttons.addElement(b); 93: } 94: 95: /** 96: * Removed a given button from this group. 97: * 98: * @param b the button to remove 99: */ 100: public void remove(AbstractButton b) 101: { 102: b.getModel().setGroup(null); 103: buttons.removeElement(b); 104: } 105: 106: /** 107: * Returns the currently added buttons. 108: * 109: * @return <code>Enumeration</code> over all added buttons 110: */ 111: public Enumeration getElements() 112: { 113: return buttons.elements(); 114: } 115: 116: /** 117: * Returns the currently selected button model. 118: * 119: * @return the currently selected button model, null if none was selected 120: * yet 121: */ 122: public ButtonModel getSelection() 123: { 124: return sel; 125: } 126: 127: /** 128: * DOCUMENT ME! 129: * 130: * @param m DOCUMENT ME! 131: * 132: * @return DOCUMENT ME! 133: */ 134: AbstractButton FindButton(ButtonModel m) 135: { 136: for (int i = 0; i < buttons.size(); i++) 137: { 138: AbstractButton a = (AbstractButton) buttons.get(i); 139: if (a.getModel() == m) 140: return a; 141: } 142: return null; 143: } 144: 145: /** 146: * Sets the currently selected button model. Only one button of a group can 147: * be selected at a time. 148: * 149: * @param m the model to select 150: * @param b true if this button is to be selected, false otherwise 151: */ 152: public void setSelected(ButtonModel m, boolean b) 153: { 154: if ((sel != m || b) && (! b || sel == m)) 155: return; 156: 157: if (b && sel != m) 158: { 159: ButtonModel old = sel; 160: sel = m; 161: 162: if (old != null) 163: old.setSelected(false); 164: AbstractButton button = FindButton(old); 165: if (button != null) 166: button.repaint(); 167: } 168: else if (!b && sel == m) 169: m.setSelected(true); 170: } 171: 172: /** 173: * Checks if the given <code>ButtonModel</code> is selected in this button 174: * group. 175: * 176: * @param m DOCUMENT ME! 177: * 178: * @return true of given <code>ButtonModel</code> is selected, false 179: * otherwise 180: */ 181: public boolean isSelected(ButtonModel m) 182: { 183: return m == sel; 184: } 185: 186: /** 187: * Return the number of buttons in this button group. 188: * 189: * @return the number of buttons 190: * 191: * @since 1.3 192: */ 193: public int getButtonCount() 194: { 195: return buttons.size(); 196: } 197: }
GNU Classpath (0.18) |