J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2000-2006 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 java.awt.event; |
| 27 | |
| 28 | import java.awt.Component; |
| 29 | |
| 30 | /** |
| 31 | * An event which indicates that the mouse wheel was rotated in a component. |
| 32 | * <P> |
| 33 | * A wheel mouse is a mouse which has a wheel in place of the middle button. |
| 34 | * This wheel can be rotated towards or away from the user. Mouse wheels are |
| 35 | * most often used for scrolling, though other uses are possible. |
| 36 | * <P> |
| 37 | * A MouseWheelEvent object is passed to every <code>MouseWheelListener</code> |
| 38 | * object which registered to receive the "interesting" mouse events using the |
| 39 | * component's <code>addMouseWheelListener</code> method. Each such listener |
| 40 | * object gets a <code>MouseEvent</code> containing the mouse event. |
| 41 | * <P> |
| 42 | * Due to the mouse wheel's special relationship to scrolling Components, |
| 43 | * MouseWheelEvents are delivered somewhat differently than other MouseEvents. |
| 44 | * This is because while other MouseEvents usually affect a change on |
| 45 | * the Component directly under the mouse |
| 46 | * cursor (for instance, when clicking a button), MouseWheelEvents often have |
| 47 | * an effect away from the mouse cursor (moving the wheel while |
| 48 | * over a Component inside a ScrollPane should scroll one of the |
| 49 | * Scrollbars on the ScrollPane). |
| 50 | * <P> |
| 51 | * MouseWheelEvents start delivery from the Component underneath the |
| 52 | * mouse cursor. If MouseWheelEvents are not enabled on the |
| 53 | * Component, the event is delivered to the first ancestor |
| 54 | * Container with MouseWheelEvents enabled. This will usually be |
| 55 | * a ScrollPane with wheel scrolling enabled. The source |
| 56 | * Component and x,y coordinates will be relative to the event's |
| 57 | * final destination (the ScrollPane). This allows a complex |
| 58 | * GUI to be installed without modification into a ScrollPane, and |
| 59 | * for all MouseWheelEvents to be delivered to the ScrollPane for |
| 60 | * scrolling. |
| 61 | * <P> |
| 62 | * Some AWT Components are implemented using native widgets which |
| 63 | * display their own scrollbars and handle their own scrolling. |
| 64 | * The particular Components for which this is true will vary from |
| 65 | * platform to platform. When the mouse wheel is |
| 66 | * moved over one of these Components, the event is delivered straight to |
| 67 | * the native widget, and not propagated to ancestors. |
| 68 | * <P> |
| 69 | * Platforms offer customization of the amount of scrolling that |
| 70 | * should take place when the mouse wheel is moved. The two most |
| 71 | * common settings are to scroll a certain number of "units" |
| 72 | * (commonly lines of text in a text-based component) or an entire "block" |
| 73 | * (similar to page-up/page-down). The MouseWheelEvent offers |
| 74 | * methods for conforming to the underlying platform settings. These |
| 75 | * platform settings can be changed at any time by the user. MouseWheelEvents |
| 76 | * reflect the most recent settings. |
| 77 | * |
| 78 | * @author Brent Christian |
| 79 | * @see MouseWheelListener |
| 80 | * @see java.awt.ScrollPane |
| 81 | * @see java.awt.ScrollPane#setWheelScrollingEnabled(boolean) |
| 82 | * @see javax.swing.JScrollPane |
| 83 | * @see javax.swing.JScrollPane#setWheelScrollingEnabled(boolean) |
| 84 | * @since 1.4 |
| 85 | */ |
| 86 | |
| 87 | public class MouseWheelEvent extends MouseEvent { |
| 88 | |
| 89 | /** |
| 90 | * Constant representing scrolling by "units" (like scrolling with the |
| 91 | * arrow keys) |
| 92 | * |
| 93 | * @see #getScrollType |
| 94 | */ |
| 95 | public static final int WHEEL_UNIT_SCROLL = 0; |
| 96 | |
| 97 | /** |
| 98 | * Constant representing scrolling by a "block" (like scrolling |
| 99 | * with page-up, page-down keys) |
| 100 | * |
| 101 | * @see #getScrollType |
| 102 | */ |
| 103 | public static final int WHEEL_BLOCK_SCROLL = 1; |
| 104 | |
| 105 | /** |
| 106 | * Indicates what sort of scrolling should take place in response to this |
| 107 | * event, based on platform settings. Legal values are: |
| 108 | * <ul> |
| 109 | * <li> WHEEL_UNIT_SCROLL |
| 110 | * <li> WHEEL_BLOCK_SCROLL |
| 111 | * </ul> |
| 112 | * |
| 113 | * @see #getScrollType |
| 114 | */ |
| 115 | int scrollType; |
| 116 | |
| 117 | /** |
| 118 | * Only valid for scrollType WHEEL_UNIT_SCROLL. |
| 119 | * Indicates number of units that should be scrolled per |
| 120 | * click of mouse wheel rotation, based on platform settings. |
| 121 | * |
| 122 | * @see #getScrollAmount |
| 123 | * @see #getScrollType |
| 124 | */ |
| 125 | int scrollAmount; |
| 126 | |
| 127 | /** |
| 128 | * Indicates how far the mouse wheel was rotated. |
| 129 | * |
| 130 | * @see #getWheelRotation |
| 131 | */ |
| 132 | int wheelRotation; |
| 133 | |
| 134 | /* |
| 135 | * serialVersionUID |
| 136 | */ |
| 137 | |
| 138 | private static final long serialVersionUID = 6459879390515399677L; |
| 139 | |
| 140 | /** |
| 141 | * Constructs a <code>MouseWheelEvent</code> object with the |
| 142 | * specified source component, type, modifiers, coordinates, |
| 143 | * scroll type, scroll amount, and wheel rotation. |
| 144 | * <p>Absolute coordinates xAbs and yAbs are set to source's location on screen plus |
| 145 | * relative coordinates x and y. xAbs and yAbs are set to zero if the source is not showing. |
| 146 | * <p>Note that passing in an invalid <code>id</code> results in |
| 147 | * unspecified behavior. This method throws an |
| 148 | * <code>IllegalArgumentException</code> if <code>source</code> |
| 149 | * is <code>null</code>. |
| 150 | * |
| 151 | * @param source the <code>Component</code> that originated |
| 152 | * the event |
| 153 | * @param id the integer that identifies the event |
| 154 | * @param when a long that gives the time the event occurred |
| 155 | * @param modifiers the modifier keys down during event |
| 156 | * (shift, ctrl, alt, meta) |
| 157 | * @param x the horizontal x coordinate for the mouse location |
| 158 | * @param y the vertical y coordinate for the mouse location |
| 159 | * @param clickCount the number of mouse clicks associated with event |
| 160 | * @param popupTrigger a boolean, true if this event is a trigger for a |
| 161 | * popup-menu |
| 162 | * @param scrollType the type of scrolling which should take place in |
| 163 | * response to this event; valid values are |
| 164 | * <code>WHEEL_UNIT_SCROLL</code> and |
| 165 | * <code>WHEEL_BLOCK_SCROLL</code> |
| 166 | * @param scrollAmount for scrollType <code>WHEEL_UNIT_SCROLL</code>, |
| 167 | * the number of units to be scrolled |
| 168 | * @param wheelRotation the amount that the mouse wheel was rotated (the |
| 169 | * number of "clicks") |
| 170 | * |
| 171 | * @throws IllegalArgumentException if <code>source</code> is null |
| 172 | * @see MouseEvent#MouseEvent(java.awt.Component, int, long, int, int, int, int, boolean) |
| 173 | * @see MouseEvent#MouseEvent(java.awt.Component, int, long, int, int, int, int, int, int, boolean, int) |
| 174 | */ |
| 175 | public MouseWheelEvent (Component source, int id, long when, int modifiers, |
| 176 | int x, int y, int clickCount, boolean popupTrigger, |
| 177 | int scrollType, int scrollAmount, int wheelRotation) { |
| 178 | |
| 179 | this(source, id, when, modifiers, x, y, 0, 0, clickCount, |
| 180 | popupTrigger, scrollType, scrollAmount, wheelRotation); |
| 181 | } |
| 182 | |
| 183 | /** |
| 184 | * Constructs a <code>MouseWheelEvent</code> object with the |
| 185 | * specified source component, type, modifiers, coordinates, |
| 186 | * absolute coordinates, scroll type, scroll amount, and wheel rotation. |
| 187 | * <p>Note that passing in an invalid <code>id</code> results in |
| 188 | * unspecified behavior. This method throws an |
| 189 | * <code>IllegalArgumentException</code> if <code>source</code> |
| 190 | * is <code>null</code>.<p> |
| 191 | * Even if inconsistent values for relative and absolute coordinates are |
| 192 | * passed to the constructor, the MouseWheelEvent instance is still |
| 193 | * created and no exception is thrown. |
| 194 | * |
| 195 | * @param source the <code>Component</code> that originated |
| 196 | * the event |
| 197 | * @param id the integer that identifies the event |
| 198 | * @param when a long that gives the time the event occurred |
| 199 | * @param modifiers the modifier keys down during event |
| 200 | * (shift, ctrl, alt, meta) |
| 201 | * @param x the horizontal x coordinate for the mouse location |
| 202 | * @param y the vertical y coordinate for the mouse location |
| 203 | * @param xAbs the absolute horizontal x coordinate for the mouse location |
| 204 | * @param yAbs the absolute vertical y coordinate for the mouse location |
| 205 | * @param clickCount the number of mouse clicks associated with event |
| 206 | * @param popupTrigger a boolean, true if this event is a trigger for a |
| 207 | * popup-menu |
| 208 | * @param scrollType the type of scrolling which should take place in |
| 209 | * response to this event; valid values are |
| 210 | * <code>WHEEL_UNIT_SCROLL</code> and |
| 211 | * <code>WHEEL_BLOCK_SCROLL</code> |
| 212 | * @param scrollAmount for scrollType <code>WHEEL_UNIT_SCROLL</code>, |
| 213 | * the number of units to be scrolled |
| 214 | * @param wheelRotation the amount that the mouse wheel was rotated (the |
| 215 | * number of "clicks") |
| 216 | * |
| 217 | * @throws IllegalArgumentException if <code>source</code> is null |
| 218 | * @see MouseEvent#MouseEvent(java.awt.Component, int, long, int, int, int, int, boolean) |
| 219 | * @see MouseEvent#MouseEvent(java.awt.Component, int, long, int, int, int, int, int, int, boolean, int) |
| 220 | * @since 1.6 |
| 221 | */ |
| 222 | public MouseWheelEvent (Component source, int id, long when, int modifiers, |
| 223 | int x, int y, int xAbs, int yAbs, int clickCount, boolean popupTrigger, |
| 224 | int scrollType, int scrollAmount, int wheelRotation) { |
| 225 | |
| 226 | super(source, id, when, modifiers, x, y, xAbs, yAbs, clickCount, |
| 227 | popupTrigger, MouseEvent.NOBUTTON); |
| 228 | |
| 229 | this.scrollType = scrollType; |
| 230 | this.scrollAmount = scrollAmount; |
| 231 | this.wheelRotation = wheelRotation; |
| 232 | } |
| 233 | |
| 234 | /** |
| 235 | * Returns the type of scrolling that should take place in response to this |
| 236 | * event. This is determined by the native platform. Legal values are: |
| 237 | * <ul> |
| 238 | * <li> MouseWheelEvent.WHEEL_UNIT_SCROLL |
| 239 | * <li> MouseWheelEvent.WHEEL_BLOCK_SCROLL |
| 240 | * </ul> |
| 241 | * |
| 242 | * @return either MouseWheelEvent.WHEEL_UNIT_SCROLL or |
| 243 | * MouseWheelEvent.WHEEL_BLOCK_SCROLL, depending on the configuration of |
| 244 | * the native platform. |
| 245 | * @see java.awt.Adjustable#getUnitIncrement |
| 246 | * @see java.awt.Adjustable#getBlockIncrement |
| 247 | * @see javax.swing.Scrollable#getScrollableUnitIncrement |
| 248 | * @see javax.swing.Scrollable#getScrollableBlockIncrement |
| 249 | */ |
| 250 | public int getScrollType() { |
| 251 | return scrollType; |
| 252 | } |
| 253 | |
| 254 | /** |
| 255 | * Returns the number of units that should be scrolled per |
| 256 | * click of mouse wheel rotation. |
| 257 | * Only valid if <code>getScrollType</code> returns |
| 258 | * <code>MouseWheelEvent.WHEEL_UNIT_SCROLL</code> |
| 259 | * |
| 260 | * @return number of units to scroll, or an undefined value if |
| 261 | * <code>getScrollType</code> returns |
| 262 | * <code>MouseWheelEvent.WHEEL_BLOCK_SCROLL</code> |
| 263 | * @see #getScrollType |
| 264 | */ |
| 265 | public int getScrollAmount() { |
| 266 | return scrollAmount; |
| 267 | } |
| 268 | |
| 269 | /** |
| 270 | * Returns the number of "clicks" the mouse wheel was rotated. |
| 271 | * |
| 272 | * @return negative values if the mouse wheel was rotated up/away from |
| 273 | * the user, and positive values if the mouse wheel was rotated down/ |
| 274 | * towards the user |
| 275 | */ |
| 276 | public int getWheelRotation() { |
| 277 | return wheelRotation; |
| 278 | } |
| 279 | |
| 280 | /** |
| 281 | * This is a convenience method to aid in the implementation of |
| 282 | * the common-case MouseWheelListener - to scroll a ScrollPane or |
| 283 | * JScrollPane by an amount which conforms to the platform settings. |
| 284 | * (Note, however, that <code>ScrollPane</code> and |
| 285 | * <code>JScrollPane</code> already have this functionality built in.) |
| 286 | * <P> |
| 287 | * This method returns the number of units to scroll when scroll type is |
| 288 | * MouseWheelEvent.WHEEL_UNIT_SCROLL, and should only be called if |
| 289 | * <code>getScrollType</code> returns MouseWheelEvent.WHEEL_UNIT_SCROLL. |
| 290 | * <P> |
| 291 | * Direction of scroll, amount of wheel movement, |
| 292 | * and platform settings for wheel scrolling are all accounted for. |
| 293 | * This method does not and cannot take into account value of the |
| 294 | * Adjustable/Scrollable unit increment, as this will vary among |
| 295 | * scrolling components. |
| 296 | * <P> |
| 297 | * A simplified example of how this method might be used in a |
| 298 | * listener: |
| 299 | * <pre> |
| 300 | * mouseWheelMoved(MouseWheelEvent event) { |
| 301 | * ScrollPane sp = getScrollPaneFromSomewhere(); |
| 302 | * Adjustable adj = sp.getVAdjustable() |
| 303 | * if (MouseWheelEvent.getScrollType() == WHEEL_UNIT_SCROLL) { |
| 304 | * int totalScrollAmount = |
| 305 | * event.getUnitsToScroll() * |
| 306 | * adj.getUnitIncrement(); |
| 307 | * adj.setValue(adj.getValue() + totalScrollAmount); |
| 308 | * } |
| 309 | * } |
| 310 | * </pre> |
| 311 | * |
| 312 | * @return the number of units to scroll based on the direction and amount |
| 313 | * of mouse wheel rotation, and on the wheel scrolling settings of the |
| 314 | * native platform |
| 315 | * @see #getScrollType |
| 316 | * @see #getScrollAmount |
| 317 | * @see MouseWheelListener |
| 318 | * @see java.awt.Adjustable |
| 319 | * @see java.awt.Adjustable#getUnitIncrement |
| 320 | * @see javax.swing.Scrollable |
| 321 | * @see javax.swing.Scrollable#getScrollableUnitIncrement |
| 322 | * @see java.awt.ScrollPane |
| 323 | * @see java.awt.ScrollPane#setWheelScrollingEnabled |
| 324 | * @see javax.swing.JScrollPane |
| 325 | * @see javax.swing.JScrollPane#setWheelScrollingEnabled |
| 326 | */ |
| 327 | public int getUnitsToScroll() { |
| 328 | return scrollAmount * wheelRotation; |
| 329 | } |
| 330 | |
| 331 | /** |
| 332 | * Returns a parameter string identifying this event. |
| 333 | * This method is useful for event-logging and for debugging. |
| 334 | * |
| 335 | * @return a string identifying the event and its attributes |
| 336 | */ |
| 337 | public String paramString() { |
| 338 | String scrollTypeStr = null; |
| 339 | |
| 340 | if (getScrollType() == WHEEL_UNIT_SCROLL) { |
| 341 | scrollTypeStr = "WHEEL_UNIT_SCROLL"; |
| 342 | } |
| 343 | else if (getScrollType() == WHEEL_BLOCK_SCROLL) { |
| 344 | scrollTypeStr = "WHEEL_BLOCK_SCROLL"; |
| 345 | } |
| 346 | else { |
| 347 | scrollTypeStr = "unknown scroll type"; |
| 348 | } |
| 349 | return super.paramString()+",scrollType="+scrollTypeStr+ |
| 350 | ",scrollAmount="+getScrollAmount()+",wheelRotation="+ |
| 351 | getWheelRotation(); |
| 352 | } |
| 353 | } |