J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1997-1998 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * |
| 4 | * Redistribution and use in source and binary forms, with or without |
| 5 | * modification, are permitted provided that the following conditions |
| 6 | * are met: |
| 7 | * |
| 8 | * - Redistributions of source code must retain the above copyright |
| 9 | * notice, this list of conditions and the following disclaimer. |
| 10 | * |
| 11 | * - Redistributions in binary form must reproduce the above copyright |
| 12 | * notice, this list of conditions and the following disclaimer in the |
| 13 | * documentation and/or other materials provided with the distribution. |
| 14 | * |
| 15 | * - Neither the name of Sun Microsystems nor the names of its |
| 16 | * contributors may be used to endorse or promote products derived |
| 17 | * from this software without specific prior written permission. |
| 18 | * |
| 19 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS |
| 20 | * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, |
| 21 | * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| 22 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
| 23 | * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| 24 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| 25 | * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| 26 | * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
| 27 | * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| 28 | * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| 29 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 30 | */ |
| 31 | |
| 32 | /* |
| 33 | */ |
| 34 | |
| 35 | import javax.swing.tree.DefaultMutableTreeNode; |
| 36 | import java.awt.Color; |
| 37 | import java.awt.Font; |
| 38 | import java.awt.Toolkit; |
| 39 | import java.util.Random; |
| 40 | |
| 41 | /** |
| 42 | * DynamicTreeNode illustrates one of the possible ways in which dynamic |
| 43 | * loading can be used in tree. The basic premise behind this is that |
| 44 | * getChildCount() will be messaged from JTreeModel before any children |
| 45 | * are asked for. So, the first time getChildCount() is issued the |
| 46 | * children are loaded.<p> |
| 47 | * It should be noted that isLeaf will also be messaged from the model. |
| 48 | * The default behavior of TreeNode is to message getChildCount to |
| 49 | * determine this. As such, isLeaf is subclassed to always return false.<p> |
| 50 | * There are others ways this could be accomplished as well. Instead of |
| 51 | * subclassing TreeNode you could subclass JTreeModel and do the same |
| 52 | * thing in getChildCount(). Or, if you aren't using TreeNode you could |
| 53 | * write your own TreeModel implementation. |
| 54 | * Another solution would be to listen for TreeNodeExpansion events and |
| 55 | * the first time a node has been expanded post the appropriate insertion |
| 56 | * events. I would not recommend this approach though, the other two |
| 57 | * are much simpler and cleaner (and are faster from the perspective of |
| 58 | * how tree deals with it). |
| 59 | * |
| 60 | * NOTE: getAllowsChildren() can be messaged before getChildCount(). |
| 61 | * For this example the nodes always allow children, so it isn't |
| 62 | * a problem, but if you do support true leaf nodes you may want |
| 63 | * to check for loading in getAllowsChildren too. |
| 64 | * |
| 65 | * @author Scott Violet |
| 66 | */ |
| 67 | |
| 68 | public class DynamicTreeNode extends DefaultMutableTreeNode |
| 69 | { |
| 70 | // Class stuff. |
| 71 | /** Number of names. */ |
| 72 | static protected float nameCount; |
| 73 | |
| 74 | /** Names to use for children. */ |
| 75 | static protected String[] names; |
| 76 | |
| 77 | /** Potential fonts used to draw with. */ |
| 78 | static protected Font[] fonts; |
| 79 | |
| 80 | /** Used to generate the names. */ |
| 81 | static protected Random nameGen; |
| 82 | |
| 83 | /** Number of children to create for each node. */ |
| 84 | static protected final int DefaultChildrenCount = 7; |
| 85 | |
| 86 | static { |
| 87 | String[] fontNames; |
| 88 | |
| 89 | try { |
| 90 | fontNames = Toolkit.getDefaultToolkit().getFontList(); |
| 91 | } catch (Exception e) { |
| 92 | fontNames = null; |
| 93 | } |
| 94 | if(fontNames == null || fontNames.length == 0) { |
| 95 | names = new String[] {"Mark Andrews", "Tom Ball", "Alan Chung", |
| 96 | "Rob Davis", "Jeff Dinkins", |
| 97 | "Amy Fowler", "James Gosling", |
| 98 | "David Karlton", "Dave Kloba", |
| 99 | "Dave Moore", "Hans Muller", |
| 100 | "Rick Levenson", "Tim Prinzing", |
| 101 | "Chester Rose", "Ray Ryan", |
| 102 | "Georges Saab", "Scott Violet", |
| 103 | "Kathy Walrath", "Arnaud Weber" }; |
| 104 | } |
| 105 | else { |
| 106 | /* Create the Fonts, creating fonts is slow, much better to |
| 107 | do it once. */ |
| 108 | int fontSize = 12; |
| 109 | |
| 110 | names = fontNames; |
| 111 | fonts = new Font[names.length]; |
| 112 | for(int counter = 0, maxCounter = names.length; |
| 113 | counter < maxCounter; counter++) { |
| 114 | try { |
| 115 | fonts[counter] = new Font(fontNames[counter], 0, fontSize); |
| 116 | } |
| 117 | catch (Exception e) { |
| 118 | fonts[counter] = null; |
| 119 | } |
| 120 | fontSize = ((fontSize + 2 - 12) % 12) + 12; |
| 121 | } |
| 122 | } |
| 123 | nameCount = (float)names.length; |
| 124 | nameGen = new Random(System.currentTimeMillis()); |
| 125 | } |
| 126 | |
| 127 | |
| 128 | /** Have the children of this node been loaded yet? */ |
| 129 | protected boolean hasLoaded; |
| 130 | |
| 131 | /** |
| 132 | * Constructs a new DynamicTreeNode instance with o as the user |
| 133 | * object. |
| 134 | */ |
| 135 | public DynamicTreeNode(Object o) { |
| 136 | super(o); |
| 137 | } |
| 138 | |
| 139 | public boolean isLeaf() { |
| 140 | return false; |
| 141 | } |
| 142 | |
| 143 | /** |
| 144 | * If hasLoaded is false, meaning the children have not yet been |
| 145 | * loaded, loadChildren is messaged and super is messaged for |
| 146 | * the return value. |
| 147 | */ |
| 148 | public int getChildCount() { |
| 149 | if(!hasLoaded) { |
| 150 | loadChildren(); |
| 151 | } |
| 152 | return super.getChildCount(); |
| 153 | } |
| 154 | |
| 155 | /** |
| 156 | * Messaged the first time getChildCount is messaged. Creates |
| 157 | * children with random names from names. |
| 158 | */ |
| 159 | protected void loadChildren() { |
| 160 | DynamicTreeNode newNode; |
| 161 | Font font; |
| 162 | int randomIndex; |
| 163 | SampleData data; |
| 164 | |
| 165 | for(int counter = 0; counter < DynamicTreeNode.DefaultChildrenCount; |
| 166 | counter++) { |
| 167 | randomIndex = (int)(nameGen.nextFloat() * nameCount); |
| 168 | if(fonts != null) |
| 169 | font = fonts[randomIndex]; |
| 170 | else |
| 171 | font = null; |
| 172 | if(counter % 2 == 0) |
| 173 | data = new SampleData(font, Color.red, names[randomIndex]); |
| 174 | else |
| 175 | data = new SampleData(font, Color.blue, names[randomIndex]); |
| 176 | newNode = new DynamicTreeNode(data); |
| 177 | /* Don't use add() here, add calls insert(newNode, getChildCount()) |
| 178 | so if you want to use add, just be sure to set hasLoaded = true |
| 179 | first. */ |
| 180 | insert(newNode, counter); |
| 181 | } |
| 182 | /* This node has now been loaded, mark it so. */ |
| 183 | hasLoaded = true; |
| 184 | } |
| 185 | } |