AWTEvent


1   /*
2    * @(#)AWTEvent.java    1.55 04/06/02
3    *
4    * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
5    * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6    */
7   
8   package java.awt;
9   
10  import java.util.EventObject  ;
11  import java.awt.event.*;
12  import java.awt.peer.ComponentPeer;
13  import java.awt.peer.LightweightPeer;
14  import java.lang.reflect.Field  ;
15  
16  /**
17   * The root event class for all AWT events.
18   * This class and its subclasses supercede the original
19   * java.awt.Event class.
20   * Subclasses of this root AWTEvent class defined outside of the
21   * java.awt.event package should define event ID values greater than
22   * the value defined by RESERVED_ID_MAX.
23   * <p>
24   * The event masks defined in this class are needed by Component subclasses
25   * which are using Component.enableEvents() to select for event types not
26   * selected by registered listeners. If a listener is registered on a
27   * component, the appropriate event mask is already set internally by the
28   * component.
29   * <p>
30   * The masks are also used to specify to which types of events an
31   * AWTEventListener should listen. The masks are bitwise-ORed together
32   * and passed to Toolkit.addAWTEventListener.
33   * 
34   * @see Component#enableEvents
35   * @see Toolkit#addAWTEventListener
36   *
37   * @see java.awt.event.ActionEvent
38   * @see java.awt.event.AdjustmentEvent
39   * @see java.awt.event.ComponentEvent
40   * @see java.awt.event.ContainerEvent
41   * @see java.awt.event.FocusEvent
42   * @see java.awt.event.InputMethodEvent
43   * @see java.awt.event.InvocationEvent
44   * @see java.awt.event.ItemEvent
45   * @see java.awt.event.HierarchyEvent
46   * @see java.awt.event.KeyEvent
47   * @see java.awt.event.MouseEvent
48   * @see java.awt.event.MouseWheelEvent
49   * @see java.awt.event.PaintEvent
50   * @see java.awt.event.TextEvent
51   * @see java.awt.event.WindowEvent
52   *
53   * @author Carl Quinn
54   * @author Amy Fowler
55   * @version 1.55 06/02/04
56   * @since 1.1
57   */
58  public abstract class AWTEvent extends EventObject   {
59      private byte bdata[];
60  
61      /**
62       * The event's id.
63       * @serial
64       * @see #getID()
65       * @see #AWTEvent
66       */
67      protected int id;
68  
69      /**
70       * Controls whether or not the event is sent back down to the peer once the
71       * source has processed it - false means it's sent to the peer; true means
72       * it's not. Semantic events always have a 'true' value since they were
73       * generated by the peer in response to a low-level event.
74       * @serial
75       * @see #consume
76       * @see #isConsumed
77       */
78      protected boolean consumed = false;
79    
80      transient boolean focusManagerIsDispatching = false;
81      transient boolean isPosted;
82   
83      /**
84       * The event mask for selecting component events.
85       */
86      public final static long COMPONENT_EVENT_MASK = 0x01;
87  
88      /**
89       * The event mask for selecting container events.
90       */
91      public final static long CONTAINER_EVENT_MASK = 0x02;
92  
93      /**
94       * The event mask for selecting focus events.
95       */
96      public final static long FOCUS_EVENT_MASK = 0x04;
97  
98      /**
99       * The event mask for selecting key events.
100      */
101     public final static long KEY_EVENT_MASK = 0x08;
102 
103     /**
104      * The event mask for selecting mouse events.
105      */
106     public final static long MOUSE_EVENT_MASK = 0x10;
107 
108     /**
109      * The event mask for selecting mouse motion events.
110      */
111     public final static long MOUSE_MOTION_EVENT_MASK = 0x20;
112 
113     /**
114      * The event mask for selecting window events.
115      */
116     public final static long WINDOW_EVENT_MASK = 0x40;
117 
118     /**
119      * The event mask for selecting action events.
120      */
121     public final static long ACTION_EVENT_MASK = 0x80;
122 
123     /**
124      * The event mask for selecting adjustment events.
125      */
126     public final static long ADJUSTMENT_EVENT_MASK = 0x100;
127 
128     /**
129      * The event mask for selecting item events.
130      */
131     public final static long ITEM_EVENT_MASK = 0x200;
132 
133     /**
134      * The event mask for selecting text events.
135      */
136     public final static long TEXT_EVENT_MASK = 0x400;
137 
138     /**
139      * The event mask for selecting input method events.
140      */
141     public final static long INPUT_METHOD_EVENT_MASK = 0x800;
142 
143     /**
144      * The pseudo event mask for enabling input methods.
145      * We're using one bit in the eventMask so we don't need
146      * a separate field inputMethodsEnabled.
147      */
148     final static long INPUT_METHODS_ENABLED_MASK = 0x1000;
149 
150     /**
151      * The event mask for selecting paint events.
152      */
153     public final static long PAINT_EVENT_MASK = 0x2000;
154 
155     /**
156      * The event mask for selecting invocation events.
157      */
158     public final static long INVOCATION_EVENT_MASK = 0x4000;
159 
160     /**
161      * The event mask for selecting hierarchy events.
162      */
163     public final static long HIERARCHY_EVENT_MASK = 0x8000;
164 
165     /**
166      * The event mask for selecting hierarchy bounds events.
167      */
168     public final static long HIERARCHY_BOUNDS_EVENT_MASK = 0x10000;
169 
170     /**
171      * The event mask for selecting mouse wheel events.
172      * @since 1.4
173      */
174     public final static long MOUSE_WHEEL_EVENT_MASK = 0x20000;
175 
176     /**
177      * The event mask for selecting window state events.
178      * @since 1.4
179      */
180     public final static long WINDOW_STATE_EVENT_MASK = 0x40000;
181 
182     /**
183      * The event mask for selecting window focus events.
184      * @since 1.4
185      */
186     public final static long WINDOW_FOCUS_EVENT_MASK = 0x80000;
187 
188     /**
189      * The maximum value for reserved AWT event IDs. Programs defining
190      * their own event IDs should use IDs greater than this value.
191      */
192     public final static int RESERVED_ID_MAX = 1999;
193 
194     // security stuff
195     private static Field   inputEvent_CanAccessSystemClipboard_Field = null;
196 
197     /*
198      * JDK 1.1 serialVersionUID
199      */
200     private static final long serialVersionUID = -1825314779160409405L;
201 
202     static {
203         /* ensure that the necessary native libraries are loaded */
204     Toolkit.loadLibraries();
205         if (!GraphicsEnvironment.isHeadless()) {
206             initIDs();
207         }
208     }
209 
210     private static synchronized Field   get_InputEvent_CanAccessSystemClipboard() { 
211         if (inputEvent_CanAccessSystemClipboard_Field == null) { 
212             inputEvent_CanAccessSystemClipboard_Field =
213                 (Field  )java.security.AccessController.doPrivileged(
214                     new java.security.PrivilegedAction  () {
215                             public Object   run() {
216                                 Field   field = null;
217                                 try {
218                                     field = InputEvent.class.
219                                         getDeclaredField("canAccessSystemClipboard");
220                                     field.setAccessible(true);
221                                     return field;
222                                 } catch (SecurityException   e) {
223                                 } catch (NoSuchFieldException   e) {
224                                 }
225                                 return null;
226                             }
227                         });
228         }
229 
230         return inputEvent_CanAccessSystemClipboard_Field;
231     }
232 
233     /**
234      * Initialize JNI field and method IDs for fields that may be
235      * accessed from C.
236      */
237     private static native void initIDs();
238 
239     /**
240      * Constructs an AWTEvent object from the parameters of a 1.0-style event.
241      * @param event the old-style event
242      */
243     public AWTEvent(Event   event) {
244         this(event.target, event.id);
245     }
246 
247     /**
248      * Constructs an AWTEvent object with the specified source object and type.
249      * @param source the object where the event originated
250      * @id the event type
251      */
252     public AWTEvent(Object   source, int id) {
253         super(source);
254     this.id = id;
255         switch(id) {
256           case ActionEvent.ACTION_PERFORMED:
257           case ItemEvent.ITEM_STATE_CHANGED:
258           case AdjustmentEvent.ADJUSTMENT_VALUE_CHANGED:
259           case TextEvent.TEXT_VALUE_CHANGED:
260             consumed = true;
261             break;
262           default:
263         }
264     }
265 
266     /**
267      * Retargets an event to a new source. This method is typically used to
268      * retarget an event to a lightweight child Component of the original
269      * heavyweight source.
270      * <p>
271      * This method is intended to be used only by event targeting subsystems,
272      * such as client-defined KeyboardFocusManagers. It is not for general
273      * client use.
274      *
275      * @param newSource the new Object to which the event should be dispatched
276      */ 
277     public void setSource(Object   newSource) {
278     if (source == newSource) {
279         return;
280     }
281  
282     Component   comp = null;
283     if (newSource instanceof Component  ) {
284         comp = (Component  )newSource;
285         while (comp != null && comp.peer != null &&
286            (comp.peer instanceof LightweightPeer)) {
287         comp = comp.parent;
288         }
289     }
290  
291     synchronized (this) {
292         source = newSource;
293         if (comp != null) {
294         ComponentPeer peer = comp.peer;
295         if (peer != null) {
296             nativeSetSource(peer);
297         }
298         }
299     }
300     }
301   
302     private native void nativeSetSource(ComponentPeer peer);
303  
304     /**
305      * Returns the event type.
306      */
307     public int getID() {
308         return id;
309     }
310 
311     /**
312      * Returns a String representation of this object.
313      */
314     public String   toString() {
315         String   srcName = null;
316         if (source instanceof Component  ) {
317             srcName = ((Component  )source).getName();
318         } else if (source instanceof MenuComponent  ) {
319             srcName = ((MenuComponent  )source).getName();
320         }
321     return getClass().getName() + "[" + paramString() + "] on " +
322             (srcName != null? srcName : source);
323     }
324 
325     /**
326      * Returns a string representing the state of this <code>Event</code>.
327      * This method is intended to be used only for debugging purposes, and the 
328      * content and format of the returned string may vary between 
329      * implementations. The returned string may be empty but may not be 
330      * <code>null</code>.
331      * 
332      * @return  a string representation of this event
333      */
334     public String   paramString() {
335         return "";
336     }
337 
338     /**
339      * Consumes this event, if this event can be consumed. Only low-level,
340      * system events can be consumed
341      */
342     protected void consume() {
343         switch(id) {
344           case KeyEvent.KEY_PRESSED:
345           case KeyEvent.KEY_RELEASED:
346           case MouseEvent.MOUSE_PRESSED:
347           case MouseEvent.MOUSE_RELEASED:
348           case MouseEvent.MOUSE_MOVED:
349           case MouseEvent.MOUSE_DRAGGED:
350           case MouseEvent.MOUSE_ENTERED:
351           case MouseEvent.MOUSE_EXITED:
352           case MouseEvent.MOUSE_WHEEL:
353           case InputMethodEvent.INPUT_METHOD_TEXT_CHANGED:
354           case InputMethodEvent.CARET_POSITION_CHANGED:
355               consumed = true;
356               break;
357           default:
358               // event type cannot be consumed
359         }
360     }
361 
362     /**
363      * Returns whether this event has been consumed.
364      */
365     protected boolean isConsumed() {
366         return consumed;
367     }
368 
369     /**
370      * Converts a new event to an old one (used for compatibility).
371      * If the new event cannot be converted (because no old equivalent
372      * exists) then this returns null.
373      *
374      * Note: this method is here instead of in each individual new
375      * event class in java.awt.event because we don't want to make
376      * it public and it needs to be called from java.awt.
377      */
378     Event   convertToOld() {
379         Object   src = getSource();
380         int newid = id;
381 
382         switch(id) {
383           case KeyEvent.KEY_PRESSED:
384           case KeyEvent.KEY_RELEASED:
385               KeyEvent ke = (KeyEvent)this;
386               if (ke.isActionKey()) {
387                   newid = (id == KeyEvent.KEY_PRESSED?
388                            Event.KEY_ACTION : Event.KEY_ACTION_RELEASE);
389               }
390               int keyCode = ke.getKeyCode();
391               if (keyCode == KeyEvent.VK_SHIFT ||
392                   keyCode == KeyEvent.VK_CONTROL ||
393                   keyCode == KeyEvent.VK_ALT) {
394                   return null;  // suppress modifier keys in old event model.
395               }
396               // no mask for button1 existed in old Event - strip it out
397               return new Event  (src, ke.getWhen(), newid, 0, 0,
398                                Event.getOldEventKey(ke),
399                                (ke.getModifiers() & ~InputEvent.BUTTON1_MASK));
400 
401           case MouseEvent.MOUSE_PRESSED:
402           case MouseEvent.MOUSE_RELEASED:
403           case MouseEvent.MOUSE_MOVED:
404           case MouseEvent.MOUSE_DRAGGED:
405           case MouseEvent.MOUSE_ENTERED:
406           case MouseEvent.MOUSE_EXITED:
407               MouseEvent me = (MouseEvent)this;
408               // no mask for button1 existed in old Event - strip it out
409               Event   olde = new Event  (src, me.getWhen(), newid,
410                                me.getX(), me.getY(), 0,
411                                (me.getModifiers() & ~InputEvent.BUTTON1_MASK));
412               olde.clickCount = me.getClickCount();
413               return olde;
414 
415           case FocusEvent.FOCUS_GAINED:
416               return new Event  (src, Event.GOT_FOCUS, null);
417 
418           case FocusEvent.FOCUS_LOST:
419               return new Event  (src, Event.LOST_FOCUS, null);
420 
421           case WindowEvent.WINDOW_CLOSING:
422           case WindowEvent.WINDOW_ICONIFIED:
423           case WindowEvent.WINDOW_DEICONIFIED:
424               return new Event  (src, newid, null);
425 
426           case ComponentEvent.COMPONENT_MOVED:
427               if (src instanceof Frame   || src instanceof Dialog  ) {
428                   Point   p = ((Component  )src).getLocation();
429                   return new Event  (src, 0, Event.WINDOW_MOVED, p.x, p.y, 0, 0);
430               }
431               break;
432 
433           case ActionEvent.ACTION_PERFORMED:
434               ActionEvent ae = (ActionEvent)this;
435               String   cmd;
436               if (src instanceof Button  ) {
437                   cmd = ((Button  )src).getLabel();
438               } else if (src instanceof MenuItem  ) {
439                   cmd = ((MenuItem  )src).getLabel();
440               } else {
441                   cmd = ae.getActionCommand();
442               }
443               return new Event  (src, 0, newid, 0, 0, 0, ae.getModifiers(), cmd);
444 
445           case ItemEvent.ITEM_STATE_CHANGED:
446               ItemEvent ie = (ItemEvent)this;
447               Object   arg;
448               if (src instanceof List  ) {
449                   newid = (ie.getStateChange() == ItemEvent.SELECTED?
450                            Event.LIST_SELECT : Event.LIST_DESELECT);
451                   arg = ie.getItem();
452               } else {
453                   newid = Event.ACTION_EVENT;
454                   if (src instanceof Choice  ) {
455                       arg = ie.getItem();
456 
457                   } else { // Checkbox
458                       arg = new Boolean  (ie.getStateChange() == ItemEvent.SELECTED);
459                   }
460               }
461               return new Event  (src, newid, arg);
462 
463           case AdjustmentEvent.ADJUSTMENT_VALUE_CHANGED:
464               AdjustmentEvent aje = (AdjustmentEvent)this;
465               switch(aje.getAdjustmentType()) {
466                 case AdjustmentEvent.UNIT_INCREMENT:
467                   newid = Event.SCROLL_LINE_DOWN;
468                   break;
469                 case AdjustmentEvent.UNIT_DECREMENT:
470                   newid = Event.SCROLL_LINE_UP;
471                   break;
472                 case AdjustmentEvent.BLOCK_INCREMENT:
473                   newid = Event.SCROLL_PAGE_DOWN;
474                   break;
475                 case AdjustmentEvent.BLOCK_DECREMENT:
476                   newid = Event.SCROLL_PAGE_UP;
477                   break;
478                 case AdjustmentEvent.TRACK:
479           if (aje.getValueIsAdjusting()) {
480               newid = Event.SCROLL_ABSOLUTE;
481           }
482           else {
483               newid = Event.SCROLL_END;
484           }
485                   break;
486                 default:
487                   return null;
488               }
489               return new Event  (src, newid, new Integer  (aje.getValue()));
490 
491           default:
492         }
493         return null;
494     }
495 
496     /**
497      * Copies all private data from this event into that. 
498      * Space is allocated for the copied data that will be
499      * freed when the that is finalized. Upon completion,
500      * this event is not changed.
501      */
502     void copyPrivateDataInto(AWTEvent   that) {
503     that.bdata = this.bdata;
504         // Copy canAccessSystemClipboard value from this into that.
505         if (this instanceof InputEvent && that instanceof InputEvent) {
506             Field   field = get_InputEvent_CanAccessSystemClipboard();
507             if (field != null) { 
508                 try {
509                     boolean b = field.getBoolean(this);
510                     field.setBoolean(that, b);
511                 } catch(IllegalAccessException   e) {
512                 } 
513             }
514         }
515     }
516 
517     void dispatched() {
518         if (this instanceof InputEvent) {
519             Field   field = get_InputEvent_CanAccessSystemClipboard();
520             if (field != null) { 
521                 try {
522                     field.setBoolean(this, false);
523                 } catch(IllegalAccessException   e) {
524                 } 
525             }
526         }
527     }            
528 } // class AWTEvent
529 
530
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags