1 /* 2 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. 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. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package javafx.scene.control; 27 28 import javafx.beans.property.ReadOnlyIntegerProperty; 29 import javafx.beans.property.ReadOnlyIntegerWrapper; 30 import javafx.beans.property.ReadOnlyObjectProperty; 31 import javafx.beans.property.ReadOnlyObjectWrapper; 32 import javafx.collections.ListChangeListener; 33 34 /** 35 * SelectionModel is an abstract class used by UI controls to provide a 36 * consistent API for maintaining selection. 37 * 38 * @param <T> The type of the item contained in the control that can be selected. 39 * @since JavaFX 2.0 40 */ 41 public abstract class SelectionModel<T> { 42 43 /*************************************************************************** 44 * * 45 * Selection Properties * 46 * * 47 **************************************************************************/ 48 49 /** 50 * <p>Refers to the selected index property, which is used to indicate 51 * the currently selected index value in the selection model. The selected 52 * index is either -1, 53 * to represent that there is no selection, or an integer value that is within 54 * the range of the underlying data model size. 55 * 56 * <p>The selected index property is most commonly used when the selection 57 * model only allows single selection, but is equally applicable when in 58 * multiple selection mode. When in this mode, the selected index will always 59 * represent the last selection made. 60 * 61 * <p>Note that in the case of multiple selection, it is possible to add 62 * a {@link ListChangeListener} to the collection returned by 63 * {@link MultipleSelectionModel#getSelectedIndices()} to be informed whenever 64 * the selection changes, and this will also work in the case of single selection. 65 */ 66 public final ReadOnlyIntegerProperty selectedIndexProperty() { return selectedIndex.getReadOnlyProperty(); } 67 private ReadOnlyIntegerWrapper selectedIndex = new ReadOnlyIntegerWrapper(this, "selectedIndex", -1); 68 protected final void setSelectedIndex(int value) { selectedIndex.set(value); } 69 70 /** 71 * <p>Returns the integer value indicating the currently selected index in 72 * this model. If there are multiple items selected, this will return the 73 * most recent selection made. 74 * 75 * <p>Note that the returned value is a snapshot in time - if you wish to 76 * observe the selection model for changes to the selected index, you can 77 * add a ChangeListener as such: 78 * 79 * <pre><code> 80 * SelectionModel sm = ...; 81 * InvalidationListener listener = ...; 82 * sm.selectedIndexProperty().addListener(listener); 83 * </code></pre> 84 */ 85 public final int getSelectedIndex() { return selectedIndexProperty().get(); } 86 87 /** 88 * <p>Refers to the selected item property, which is used to indicate 89 * the currently selected item in the selection model. The selected item is 90 * either null, 91 * to represent that there is no selection, or an Object that is retrieved 92 * from the underlying data model of the control the selection model is 93 * associated with. 94 * 95 * <p>The selected item property is most commonly used when the selection 96 * model is set to be single selection, but is equally applicable when in 97 * multiple selection mode. When in this mode, the selected item will always 98 * represent the last selection made. 99 */ 100 public final ReadOnlyObjectProperty<T> selectedItemProperty() { return selectedItem.getReadOnlyProperty(); } 101 private ReadOnlyObjectWrapper<T> selectedItem = new ReadOnlyObjectWrapper<T>(this, "selectedItem"); 102 protected final void setSelectedItem(T value) { selectedItem.set(value); } 103 104 /** 105 * Returns the currently selected object (which resides in the selected index 106 * position). If there are multiple items selected, this will return the 107 * object contained at the index returned by getSelectedIndex() (which is 108 * always the index to the most recently selected item). 109 * 110 * <p>Note that the returned value is a snapshot in time - if you wish to 111 * observe the selection model for changes to the selected item, you can 112 * add a ChangeListener as such: 113 * 114 * <pre><code> 115 * SelectionModel sm = ...; 116 * InvalidationListener listener = ...; 117 * sm.selectedItemProperty().addListener(listener); 118 * </code></pre> 119 */ 120 public final T getSelectedItem() { return selectedItemProperty().get(); } 121 122 123 /*************************************************************************** 124 * * 125 * Constructor * 126 * * 127 **************************************************************************/ 128 129 /** 130 * Creates a default SelectionModel instance. 131 */ 132 public SelectionModel() { } 133 134 135 /*************************************************************************** 136 * * 137 * Selection API * 138 * * 139 **************************************************************************/ 140 141 142 /** 143 * A method that clears any selection prior to setting the selection to the 144 * given index. The purpose of this method is to avoid having to call 145 * {@link #clearSelection()} first, meaning that observers that are listening to 146 * the {@link #selectedIndexProperty() selected index} property will not 147 * see the selected index being temporarily set to -1. 148 * 149 * @param index The index that should be the only selected index in this 150 * selection model. 151 */ 152 public abstract void clearAndSelect(int index); 153 154 /** 155 * <p>This will select the given index in the selection model, assuming the 156 * index is within the valid range (i.e. greater than or equal to zero, and 157 * less than the total number of items in the underlying data model). 158 * 159 * <p>If there is already one or more indices selected in this model, calling 160 * this method will <b>not</b> clear these selections - to do so it is 161 * necessary to first call {@link #clearSelection()}. 162 * 163 * <p>If the index is already selected, it will not be selected again, or 164 * unselected. However, if multiple selection is implemented, then calling 165 * select on an already selected index will have the effect of making the index 166 * the new selected index (as returned by {@link #getSelectedIndex()}. 167 * 168 * @param index The position of the item to select in the selection model. 169 */ 170 public abstract void select(int index); 171 172 /** 173 * <p>This method will attempt to select the index that contains the given 174 * object. It will iterate through the underlying data model until it finds 175 * an item whose value is equal to the given object. At this point it will 176 * stop iterating - this means that this method will not select multiple 177 * indices. 178 * 179 * @param obj The object to attempt to select in the underlying data model. 180 */ 181 public abstract void select(T obj); 182 183 /** 184 * <p>This method will clear the selection of the item in the given index. 185 * If the given index is not selected, nothing will happen. 186 * 187 * @param index The selected item to deselect. 188 */ 189 public abstract void clearSelection(int index); 190 191 /** 192 * <p>Clears the selection model of all selected indices. 193 */ 194 public abstract void clearSelection(); 195 196 /** 197 * <p>Convenience method to inform if the given index is currently selected 198 * in this SelectionModel. Is functionally equivalent to calling 199 * <code>getSelectedIndices().contains(index)</code>. 200 * 201 * @param index The index to check as to whether it is currently selected 202 * or not. 203 * @return True if the given index is selected, false otherwise. 204 */ 205 public abstract boolean isSelected(int index); 206 207 /** 208 * This method is available to test whether there are any selected 209 * indices/items. It will return true if there are <b>no</b> selected items, 210 * and false if there are. 211 * 212 * @return Will return true if there are <b>no</b> selected items, and false 213 * if there are. 214 */ 215 public abstract boolean isEmpty(); 216 217 /** 218 * <p>This method will attempt to select the index directly before the current 219 * focused index. If clearSelection is not called first, this method 220 * will have the result of selecting the previous index, whilst retaining 221 * the selection of any other currently selected indices.</p> 222 * 223 * <p>Calling this method will only succeed if:</p> 224 * 225 * <ul> 226 * <li>There is currently a lead/focused index. 227 * <li>The lead/focus index is not the first index in the control. 228 * <li>The previous index is not already selected. 229 * </ul> 230 * 231 * <p>If any of these conditions is false, no selection event will take 232 * place.</p> 233 */ 234 public abstract void selectPrevious(); 235 236 /** 237 * <p>This method will attempt to select the index directly after the current 238 * focused index. If clearSelection is not called first, this method 239 * will have the result of selecting the next index, whilst retaining 240 * the selection of any other currently selected indices.</p> 241 * 242 * <p>Calling this method will only succeed if:</p> 243 * 244 * <ul> 245 * <li>There is currently a lead/focused index. 246 * <li>The lead/focus index is not the last index in the control. 247 * <li>The next index is not already selected. 248 * </ul> 249 * 250 * <p>If any of these conditions is false, no selection event will take 251 * place.</p> 252 */ 253 public abstract void selectNext(); 254 255 /** 256 * <p>This method will attempt to select the first index in the control. If 257 * clearSelection is not called first, this method 258 * will have the result of selecting the first index, whilst retaining 259 * the selection of any other currently selected indices.</p> 260 * 261 * <p>If the first index is already selected, calling this method will have 262 * no result, and no selection event will take place.</p> 263 */ 264 public abstract void selectFirst(); 265 266 /** 267 * <p>This method will attempt to select the last index in the control. If 268 * clearSelection is not called first, this method 269 * will have the result of selecting the last index, whilst retaining 270 * the selection of any other currently selected indices.</p> 271 * 272 * <p>If the last index is already selected, calling this method will have 273 * no result, and no selection event will take place.</p> 274 */ 275 public abstract void selectLast(); 276 }