J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1997-2003 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package javax.swing.event; |
| 27 | |
| 28 | import java.util.EventObject; |
| 29 | import javax.swing.tree.TreePath; |
| 30 | |
| 31 | |
| 32 | /** |
| 33 | * Encapsulates information describing changes to a tree model, and |
| 34 | * used to notify tree model listeners of the change. |
| 35 | * For more information and examples see |
| 36 | * <a |
| 37 | href="http://java.sun.com/docs/books/tutorial/uiswing/events/treemodellistener.html">How to Write a Tree Model Listener</a>, |
| 38 | * a section in <em>The Java Tutorial.</em> |
| 39 | * <p> |
| 40 | * <strong>Warning:</strong> |
| 41 | * Serialized objects of this class will not be compatible with |
| 42 | * future Swing releases. The current serialization support is |
| 43 | * appropriate for short term storage or RMI between applications running |
| 44 | * the same version of Swing. As of 1.4, support for long term storage |
| 45 | * of all JavaBeans<sup><font size="-2">TM</font></sup> |
| 46 | * has been added to the <code>java.beans</code> package. |
| 47 | * Please see {@link java.beans.XMLEncoder}. |
| 48 | * |
| 49 | * @author Rob Davis |
| 50 | * @author Ray Ryan |
| 51 | * @author Scott Violet |
| 52 | */ |
| 53 | public class TreeModelEvent extends EventObject { |
| 54 | /** Path to the parent of the nodes that have changed. */ |
| 55 | protected TreePath path; |
| 56 | /** Indices identifying the position of where the children were. */ |
| 57 | protected int[] childIndices; |
| 58 | /** Children that have been removed. */ |
| 59 | protected Object[] children; |
| 60 | |
| 61 | /** |
| 62 | * Used to create an event when nodes have been changed, inserted, or |
| 63 | * removed, identifying the path to the parent of the modified items as |
| 64 | * an array of Objects. All of the modified objects are siblings which are |
| 65 | * direct descendents (not grandchildren) of the specified parent. |
| 66 | * The positions at which the inserts, deletes, or changes occurred are |
| 67 | * specified by an array of <code>int</code>. The indexes in that array |
| 68 | * must be in order, from lowest to highest. |
| 69 | * <p> |
| 70 | * For changes, the indexes in the model correspond exactly to the indexes |
| 71 | * of items currently displayed in the UI. As a result, it is not really |
| 72 | * critical if the indexes are not in their exact order. But after multiple |
| 73 | * inserts or deletes, the items currently in the UI no longer correspond |
| 74 | * to the items in the model. It is therefore critical to specify the |
| 75 | * indexes properly for inserts and deletes. |
| 76 | * <p> |
| 77 | * For inserts, the indexes represent the <i>final</i> state of the tree, |
| 78 | * after the inserts have occurred. Since the indexes must be specified in |
| 79 | * order, the most natural processing methodology is to do the inserts |
| 80 | * starting at the lowest index and working towards the highest. Accumulate |
| 81 | * a Vector of <code>Integer</code> objects that specify the |
| 82 | * insert-locations as you go, then convert the Vector to an |
| 83 | * array of <code>int</code> to create the event. When the postition-index |
| 84 | * equals zero, the node is inserted at the beginning of the list. When the |
| 85 | * position index equals the size of the list, the node is "inserted" at |
| 86 | * (appended to) the end of the list. |
| 87 | * <p> |
| 88 | * For deletes, the indexes represent the <i>initial</i> state of the tree, |
| 89 | * before the deletes have occurred. Since the indexes must be specified in |
| 90 | * order, the most natural processing methodology is to use a delete-counter. |
| 91 | * Start by initializing the counter to zero and start work through the |
| 92 | * list from lowest to higest. Every time you do a delete, add the current |
| 93 | * value of the delete-counter to the index-position where the delete occurred, |
| 94 | * and append the result to a Vector of delete-locations, using |
| 95 | * <code>addElement()</code>. Then increment the delete-counter. The index |
| 96 | * positions stored in the Vector therefore reflect the effects of all previous |
| 97 | * deletes, so they represent each object's position in the initial tree. |
| 98 | * (You could also start at the highest index and working back towards the |
| 99 | * lowest, accumulating a Vector of delete-locations as you go using the |
| 100 | * <code>insertElementAt(Integer, 0)</code>.) However you produce the Vector |
| 101 | * of initial-positions, you then need to convert the Vector of <code>Integer</code> |
| 102 | * objects to an array of <code>int</code> to create the event. |
| 103 | * <p> |
| 104 | * <b>Notes:</b><ul> |
| 105 | * <li>Like the <code>insertNodeInto</code> method in the |
| 106 | * <code>DefaultTreeModel</code> class, <code>insertElementAt</code> |
| 107 | * appends to the <code>Vector</code> when the index matches the size |
| 108 | * of the vector. So you can use <code>insertElementAt(Integer, 0)</code> |
| 109 | * even when the vector is empty. |
| 110 | * <ul>To create a node changed event for the root node, specify the parent |
| 111 | * and the child indices as <code>null</code>. |
| 112 | * </ul> |
| 113 | * |
| 114 | * @param source the Object responsible for generating the event (typically |
| 115 | * the creator of the event object passes <code>this</code> |
| 116 | * for its value) |
| 117 | * @param path an array of Object identifying the path to the |
| 118 | * parent of the modified item(s), where the first element |
| 119 | * of the array is the Object stored at the root node and |
| 120 | * the last element is the Object stored at the parent node |
| 121 | * @param childIndices an array of <code>int</code> that specifies the |
| 122 | * index values of the removed items. The indices must be |
| 123 | * in sorted order, from lowest to highest |
| 124 | * @param children an array of Object containing the inserted, removed, or |
| 125 | * changed objects |
| 126 | * @see TreePath |
| 127 | */ |
| 128 | public TreeModelEvent(Object source, Object[] path, int[] childIndices, |
| 129 | Object[] children) |
| 130 | { |
| 131 | this(source, new TreePath(path), childIndices, children); |
| 132 | } |
| 133 | |
| 134 | /** |
| 135 | * Used to create an event when nodes have been changed, inserted, or |
| 136 | * removed, identifying the path to the parent of the modified items as |
| 137 | * a TreePath object. For more information on how to specify the indexes |
| 138 | * and objects, see |
| 139 | * <code>TreeModelEvent(Object,Object[],int[],Object[])</code>. |
| 140 | * |
| 141 | * @param source the Object responsible for generating the event (typically |
| 142 | * the creator of the event object passes <code>this</code> |
| 143 | * for its value) |
| 144 | * @param path a TreePath object that identifies the path to the |
| 145 | * parent of the modified item(s) |
| 146 | * @param childIndices an array of <code>int</code> that specifies the |
| 147 | * index values of the modified items |
| 148 | * @param children an array of Object containing the inserted, removed, or |
| 149 | * changed objects |
| 150 | * |
| 151 | * @see #TreeModelEvent(Object,Object[],int[],Object[]) |
| 152 | */ |
| 153 | public TreeModelEvent(Object source, TreePath path, int[] childIndices, |
| 154 | Object[] children) |
| 155 | { |
| 156 | super(source); |
| 157 | this.path = path; |
| 158 | this.childIndices = childIndices; |
| 159 | this.children = children; |
| 160 | } |
| 161 | |
| 162 | /** |
| 163 | * Used to create an event when the node structure has changed in some way, |
| 164 | * identifying the path to the root of a modified subtree as an array of |
| 165 | * Objects. A structure change event might involve nodes swapping position, |
| 166 | * for example, or it might encapsulate multiple inserts and deletes in the |
| 167 | * subtree stemming from the node, where the changes may have taken place at |
| 168 | * different levels of the subtree. |
| 169 | * <blockquote> |
| 170 | * <b>Note:</b><br> |
| 171 | * JTree collapses all nodes under the specified node, so that only its |
| 172 | * immediate children are visible. |
| 173 | * </blockquote> |
| 174 | * |
| 175 | * @param source the Object responsible for generating the event (typically |
| 176 | * the creator of the event object passes <code>this</code> |
| 177 | * for its value) |
| 178 | * @param path an array of Object identifying the path to the root of the |
| 179 | * modified subtree, where the first element of the array is |
| 180 | * the object stored at the root node and the last element |
| 181 | * is the object stored at the changed node |
| 182 | * @see TreePath |
| 183 | */ |
| 184 | public TreeModelEvent(Object source, Object[] path) |
| 185 | { |
| 186 | this(source, new TreePath(path)); |
| 187 | } |
| 188 | |
| 189 | /** |
| 190 | * Used to create an event when the node structure has changed in some way, |
| 191 | * identifying the path to the root of the modified subtree as a TreePath |
| 192 | * object. For more information on this event specification, see |
| 193 | * <code>TreeModelEvent(Object,Object[])</code>. |
| 194 | * |
| 195 | * @param source the Object responsible for generating the event (typically |
| 196 | * the creator of the event object passes <code>this</code> |
| 197 | * for its value) |
| 198 | * @param path a TreePath object that identifies the path to the |
| 199 | * change. In the DefaultTreeModel, |
| 200 | * this object contains an array of user-data objects, |
| 201 | * but a subclass of TreePath could use some totally |
| 202 | * different mechanism -- for example, a node ID number |
| 203 | * |
| 204 | * @see #TreeModelEvent(Object,Object[]) |
| 205 | */ |
| 206 | public TreeModelEvent(Object source, TreePath path) |
| 207 | { |
| 208 | super(source); |
| 209 | this.path = path; |
| 210 | this.childIndices = new int[0]; |
| 211 | } |
| 212 | |
| 213 | /** |
| 214 | * For all events, except treeStructureChanged, |
| 215 | * returns the parent of the changed nodes. |
| 216 | * For treeStructureChanged events, returns the ancestor of the |
| 217 | * structure that has changed. This and |
| 218 | * <code>getChildIndices</code> are used to get a list of the effected |
| 219 | * nodes. |
| 220 | * <p> |
| 221 | * The one exception to this is a treeNodesChanged event that is to |
| 222 | * identify the root, in which case this will return the root |
| 223 | * and <code>getChildIndices</code> will return null. |
| 224 | * |
| 225 | * @return the TreePath used in identifying the changed nodes. |
| 226 | * @see TreePath#getLastPathComponent |
| 227 | */ |
| 228 | public TreePath getTreePath() { return path; } |
| 229 | |
| 230 | /** |
| 231 | * Convenience method to get the array of objects from the TreePath |
| 232 | * instance that this event wraps. |
| 233 | * |
| 234 | * @return an array of Objects, where the first Object is the one |
| 235 | * stored at the root and the last object is the one |
| 236 | * stored at the node identified by the path |
| 237 | */ |
| 238 | public Object[] getPath() { |
| 239 | if(path != null) |
| 240 | return path.getPath(); |
| 241 | return null; |
| 242 | } |
| 243 | |
| 244 | /** |
| 245 | * Returns the objects that are children of the node identified by |
| 246 | * <code>getPath</code> at the locations specified by |
| 247 | * <code>getChildIndices</code>. If this is a removal event the |
| 248 | * returned objects are no longer children of the parent node. |
| 249 | * |
| 250 | * @return an array of Object containing the children specified by |
| 251 | * the event |
| 252 | * @see #getPath |
| 253 | * @see #getChildIndices |
| 254 | */ |
| 255 | public Object[] getChildren() { |
| 256 | if(children != null) { |
| 257 | int cCount = children.length; |
| 258 | Object[] retChildren = new Object[cCount]; |
| 259 | |
| 260 | System.arraycopy(children, 0, retChildren, 0, cCount); |
| 261 | return retChildren; |
| 262 | } |
| 263 | return null; |
| 264 | } |
| 265 | |
| 266 | /** |
| 267 | * Returns the values of the child indexes. If this is a removal event |
| 268 | * the indexes point to locations in the initial list where items |
| 269 | * were removed. If it is an insert, the indices point to locations |
| 270 | * in the final list where the items were added. For node changes, |
| 271 | * the indices point to the locations of the modified nodes. |
| 272 | * |
| 273 | * @return an array of <code>int</code> containing index locations for |
| 274 | * the children specified by the event |
| 275 | */ |
| 276 | public int[] getChildIndices() { |
| 277 | if(childIndices != null) { |
| 278 | int cCount = childIndices.length; |
| 279 | int[] retArray = new int[cCount]; |
| 280 | |
| 281 | System.arraycopy(childIndices, 0, retArray, 0, cCount); |
| 282 | return retArray; |
| 283 | } |
| 284 | return null; |
| 285 | } |
| 286 | |
| 287 | /** |
| 288 | * Returns a string that displays and identifies this object's |
| 289 | * properties. |
| 290 | * |
| 291 | * @return a String representation of this object |
| 292 | */ |
| 293 | public String toString() { |
| 294 | StringBuffer retBuffer = new StringBuffer(); |
| 295 | |
| 296 | retBuffer.append(getClass().getName() + " " + |
| 297 | Integer.toString(hashCode())); |
| 298 | if(path != null) |
| 299 | retBuffer.append(" path " + path); |
| 300 | if(childIndices != null) { |
| 301 | retBuffer.append(" indices [ "); |
| 302 | for(int counter = 0; counter < childIndices.length; counter++) |
| 303 | retBuffer.append(Integer.toString(childIndices[counter])+ " "); |
| 304 | retBuffer.append("]"); |
| 305 | } |
| 306 | if(children != null) { |
| 307 | retBuffer.append(" children [ "); |
| 308 | for(int counter = 0; counter < children.length; counter++) |
| 309 | retBuffer.append(children[counter] + " "); |
| 310 | retBuffer.append("]"); |
| 311 | } |
| 312 | return retBuffer.toString(); |
| 313 | } |
| 314 | } |