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1: /* DefaultComboBoxModel.java -- 2: Copyright (C) 2002, 2004, 2005, 2006, 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.Arrays; 42: import java.util.Vector; 43: 44: import javax.swing.event.ListDataEvent; 45: 46: 47: /** 48: * A model that stores a list of elements and a selected item (which may be 49: * <code>null</code>). Changes to the model are signalled to listeners using 50: * {@link ListDataEvent}. This model is designed for use by the 51: * {@link JComboBox} component. 52: * 53: * @author Andrew Selkirk 54: * @author Olga Rodimina 55: * @author Robert Schuster 56: */ 57: public class DefaultComboBoxModel extends AbstractListModel 58: implements MutableComboBoxModel, Serializable 59: { 60: private static final long serialVersionUID = 6698657703676921904L; 61: 62: /** 63: * Storage for the elements in the model's list. 64: */ 65: private Vector list; 66: 67: /** 68: * The selected item (<code>null</code> indicates no selection). 69: */ 70: private Object selectedItem = null; 71: 72: /** 73: * Creates a new model, initially empty. 74: */ 75: public DefaultComboBoxModel() 76: { 77: list = new Vector(); 78: } 79: 80: /** 81: * Creates a new model and initializes its item list to the values in the 82: * given array. The selected item is set to the first item in the array, or 83: * <code>null</code> if the array length is zero. 84: * 85: * @param items an array containing items for the model (<code>null</code> 86: * not permitted). 87: * 88: * @throws NullPointerException if <code>items</code> is <code>null</code>. 89: */ 90: public DefaultComboBoxModel(Object[] items) 91: { 92: list = new Vector(Arrays.asList(items)); 93: if (list.size() > 0) 94: selectedItem = list.get(0); 95: } 96: 97: /** 98: * Creates a new model and initializes its item list to the values in the 99: * given vector. The selected item is set to the first item in the vector, 100: * or <code>null</code> if the vector length is zero. 101: * 102: * @param vector a vector containing items for the model (<code>null</code> 103: * not permitted). 104: * 105: * @throws NullPointerException if <code>vector</code> is <code>null</code>. 106: */ 107: public DefaultComboBoxModel(Vector<?> vector) 108: { 109: this.list = vector; 110: if (getSize() > 0) 111: selectedItem = vector.get(0); 112: } 113: 114: /** 115: * Adds an element to the model's item list and sends a {@link ListDataEvent} 116: * to all registered listeners. If the new element is the first item added 117: * to the list, and the selected item is <code>null</code>, the new element 118: * is set as the selected item. 119: * 120: * @param object item to add to the model's item list. 121: */ 122: public void addElement(Object object) 123: { 124: list.addElement(object); 125: int index = list.size() - 1; 126: fireIntervalAdded(this, index, index); 127: if (list.size() == 1 && selectedItem == null) 128: setSelectedItem(object); 129: } 130: 131: /** 132: * Removes the element at the specified index from the model's item list 133: * and sends a {@link ListDataEvent} to all registered listeners. If the 134: * element removed was the selected item, then the preceding element becomes 135: * the new selected item (or the next element, if there is no preceding 136: * element). 137: * 138: * @param index the index of the item to remove. 139: * 140: * @throws ArrayIndexOutOfBoundsException if <code>index</code> is out of 141: * bounds. 142: */ 143: public void removeElementAt(int index) 144: { 145: int selected = getIndexOf(selectedItem); 146: if (selected == index) // choose a new selected item 147: { 148: if (selected > 0) 149: setSelectedItem(getElementAt(selected - 1)); 150: else 151: setSelectedItem(getElementAt(selected + 1)); 152: } 153: list.removeElementAt(index); 154: fireIntervalRemoved(this, index, index); 155: } 156: 157: /** 158: * Adds an element at the specified index in the model's item list 159: * and sends a {@link ListDataEvent} to all registered listeners. 160: * 161: * @param object element to insert 162: * @param index index specifing position in the list where given element 163: * should be inserted. 164: * 165: * @throws ArrayIndexOutOfBoundsException if <code>index</code> is out of 166: * bounds. 167: * 168: * @see #addElement(Object) 169: */ 170: public void insertElementAt(Object object, int index) 171: { 172: list.insertElementAt(object, index); 173: fireIntervalAdded(this, index, index); 174: } 175: 176: /** 177: * Removes an element from the model's item list and sends a 178: * {@link ListDataEvent} to all registered listeners. If the item to be 179: * removed is the current selected item, a new selected item will be set. 180: * If the element is not found in the model's item list, this method does 181: * nothing. 182: * 183: * @param object the element to remove. 184: */ 185: public void removeElement(Object object) 186: { 187: int index = getIndexOf(object); 188: if (index != -1) 189: removeElementAt(index); 190: } 191: 192: /** 193: * Removes all the items from the model's item list, resets and selected item 194: * to <code>null</code>, and sends a {@link ListDataEvent} to all registered 195: * listeners. 196: */ 197: public void removeAllElements() 198: { 199: selectedItem = null; 200: int size = getSize(); 201: if (size > 0) 202: { 203: list.clear(); 204: fireIntervalRemoved(this, 0, size - 1); 205: } 206: } 207: 208: /** 209: * Returns the number of items in the model's item list. 210: * 211: * @return The number of items in the model's item list. 212: */ 213: public int getSize() 214: { 215: return list.size(); 216: } 217: 218: /** 219: * Sets the selected item for the model and sends a {@link ListDataEvent} to 220: * all registered listeners. The start and end index of the event is set to 221: * -1 to indicate the model's selection has changed, and not its contents. 222: * 223: * @param object the new selected item (<code>null</code> permitted). 224: */ 225: public void setSelectedItem(Object object) 226: { 227: // No item is selected and object is null, so no change required. 228: if (selectedItem == null && object == null) 229: return; 230: 231: // object is already selected so no change required. 232: if (selectedItem != null && selectedItem.equals(object)) 233: return; 234: 235: // Simply return if object is not in the list. 236: if (object != null && getIndexOf(object) == -1) 237: return; 238: 239: // Here we know that object is either an item in the list or null. 240: 241: // Handle the three change cases: selectedItem is null, object is 242: // non-null; selectedItem is non-null, object is null; 243: // selectedItem is non-null, object is non-null and they're not 244: // equal. 245: selectedItem = object; 246: fireContentsChanged(this, -1, -1); 247: } 248: 249: /** 250: * Returns the selected item. 251: * 252: * @return The selected item (possibly <code>null</code>). 253: */ 254: public Object getSelectedItem() 255: { 256: return selectedItem; 257: } 258: 259: /** 260: * Returns the element at the specified index in the model's item list. 261: * 262: * @param index the element index. 263: * 264: * @return The element at the specified index in the model's item list, or 265: * <code>null</code> if the <code>index</code> is outside the bounds 266: * of the list. 267: */ 268: public Object getElementAt(int index) 269: { 270: if (index < 0 || index >= list.size()) 271: return null; 272: return list.elementAt(index); 273: } 274: 275: /** 276: * Returns the index of the specified element in the model's item list. 277: * 278: * @param object the element. 279: * 280: * @return The index of the specified element in the model's item list. 281: */ 282: public int getIndexOf(Object object) 283: { 284: return list.indexOf(object); 285: } 286: }