/*
* Copyright 1996-2007 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
package java.awt;
import java.awt.event.ActionEvent;
import java.awt.event.FocusEvent;
import java.awt.event.InputEvent;
import java.awt.event.InputMethodEvent;
import java.awt.event.InvocationEvent;
import java.awt.event.KeyEvent;
import java.awt.event.MouseEvent;
import java.awt.event.PaintEvent;
import java.awt.event.WindowEvent;
import java.awt.ActiveEvent;
import java.awt.peer.ComponentPeer;
import java.awt.TrayIcon;
import java.util.EmptyStackException;
import java.lang.ref.WeakReference;
import java.lang.reflect.InvocationTargetException;
import java.security.AccessController;
import java.security.PrivilegedAction;
import sun.awt.PeerEvent;
import sun.awt.SunToolkit;
import sun.awt.AWTAutoShutdown;
import sun.awt.AppContext;
/**
* <code>EventQueue</code> is a platform-independent class
* that queues events, both from the underlying peer classes
* and from trusted application classes.
* <p>
* It encapsulates asynchronous event dispatch machinery which
* extracts events from the queue and dispatches them by calling
* {@link #dispatchEvent(AWTEvent) dispatchEvent(AWTEvent)} method
* on this <code>EventQueue</code> with the event to be dispatched
* as an argument. The particular behavior of this machinery is
* implementation-dependent. The only requirements are that events
* which were actually enqueued to this queue (note that events
* being posted to the <code>EventQueue</code> can be coalesced)
* are dispatched:
* <dl>
* <dt> Sequentially.
* <dd> That is, it is not permitted that several events from
* this queue are dispatched simultaneously.
* <dt> In the same order as they are enqueued.
* <dd> That is, if <code>AWTEvent</code> A is enqueued
* to the <code>EventQueue</code> before
* <code>AWTEvent</code> B then event B will not be
* dispatched before event A.
* </dl>
* <p>
* Some browsers partition applets in different code bases into
* separate contexts, and establish walls between these contexts.
* In such a scenario, there will be one <code>EventQueue</code>
* per context. Other browsers place all applets into the same
* context, implying that there will be only a single, global
* <code>EventQueue</code> for all applets. This behavior is
* implementation-dependent. Consult your browser's documentation
* for more information.
* <p>
* For information on the threading issues of the event dispatch
* machinery, see <a href="doc-files/AWTThreadIssues.html#Autoshutdown"
* >AWT Threading Issues</a>.
*
* @author Thomas Ball
* @author Fred Ecks
* @author David Mendenhall
*
* @version 1.114, 06/05/07
* @since 1.1
*/
public class EventQueue {
// From Thread.java
private static int threadInitNumber;
private static synchronized int nextThreadNum() {
return threadInitNumber++;
}
private static final int LOW_PRIORITY = 0;
private static final int NORM_PRIORITY = 1;
private static final int HIGH_PRIORITY = 2;
private static final int ULTIMATE_PRIORITY = 3;
private static final int NUM_PRIORITIES = ULTIMATE_PRIORITY + 1;
/*
* We maintain one Queue for each priority that the EventQueue supports.
* That is, the EventQueue object is actually implemented as
* NUM_PRIORITIES queues and all Events on a particular internal Queue
* have identical priority. Events are pulled off the EventQueue starting
* with the Queue of highest priority. We progress in decreasing order
* across all Queues.
*/
private Queue[] queues = new Queue[NUM_PRIORITIES];
/*
* The next EventQueue on the stack, or null if this EventQueue is
* on the top of the stack. If nextQueue is non-null, requests to post
* an event are forwarded to nextQueue.
*/
private EventQueue nextQueue;
/*
* The previous EventQueue on the stack, or null if this is the
* "base" EventQueue.
*/
private EventQueue previousQueue;
private EventDispatchThread dispatchThread;
private final ThreadGroup threadGroup = Thread.currentThread()
.getThreadGroup();
private final ClassLoader classLoader = Thread.currentThread()
.getContextClassLoader();
/*
* Debugging flag -- set true and recompile to enable checking.
*/
private final static boolean debug = false;
/*
* The time stamp of the last dispatched InputEvent or ActionEvent.
*/
private long mostRecentEventTime = System.currentTimeMillis();
/**
* The modifiers field of the current event, if the current event is an
* InputEvent or ActionEvent.
*/
private WeakReference currentEvent;
/*
* Non-zero if a thread is waiting in getNextEvent(int) for an event of
* a particular ID to be posted to the queue.
*/
private int waitForID;
private final String name = "AWT-EventQueue-" + nextThreadNum();
public EventQueue() {
for (int i = 0; i < NUM_PRIORITIES; i++) {
queues[i] = new Queue();
}
/*
* NOTE: if you ever have to start the associated event dispatch
* thread at this point, be aware of the following problem:
* If this EventQueue instance is created in
* SunToolkit.createNewAppContext() the started dispatch thread
* may call AppContext.getAppContext() before createNewAppContext()
* completes thus causing mess in thread group to appcontext mapping.
*/
}
/**
* Posts a 1.1-style event to the <code>EventQueue</code>.
* If there is an existing event on the queue with the same ID
* and event source, the source <code>Component</code>'s
* <code>coalesceEvents</code> method will be called.
*
* @param theEvent an instance of <code>java.awt.AWTEvent</code>,
* or a subclass of it
* @throws NullPointerException if <code>theEvent</code> is <code>null</code>
*/
public void postEvent(AWTEvent theEvent) {
SunToolkit.flushPendingEvents();
postEventPrivate(theEvent);
}
/**
* Posts a 1.1-style event to the <code>EventQueue</code>.
* If there is an existing event on the queue with the same ID
* and event source, the source <code>Component</code>'s
* <code>coalesceEvents</code> method will be called.
*
* @param theEvent an instance of <code>java.awt.AWTEvent</code>,
* or a subclass of it
*/
final void postEventPrivate(AWTEvent theEvent) {
theEvent.isPosted = true;
synchronized (this ) {
if (dispatchThread == null && nextQueue == null) {
if (theEvent.getSource() == AWTAutoShutdown
.getInstance()) {
return;
} else {
initDispatchThread();
}
}
if (nextQueue != null) {
// Forward event to top of EventQueue stack.
nextQueue.postEventPrivate(theEvent);
return;
}
postEvent(theEvent, getPriority(theEvent));
}
}
private static int getPriority(AWTEvent theEvent) {
if (theEvent instanceof PeerEvent
&& (((PeerEvent) theEvent).getFlags() & PeerEvent.ULTIMATE_PRIORITY_EVENT) != 0) {
return ULTIMATE_PRIORITY;
}
if (theEvent instanceof PeerEvent
&& (((PeerEvent) theEvent).getFlags() & PeerEvent.PRIORITY_EVENT) != 0) {
return HIGH_PRIORITY;
}
if (theEvent instanceof PeerEvent
&& (((PeerEvent) theEvent).getFlags() & PeerEvent.LOW_PRIORITY_EVENT) != 0) {
return LOW_PRIORITY;
}
int id = theEvent.getID();
if (id == PaintEvent.PAINT || id == PaintEvent.UPDATE) {
return LOW_PRIORITY;
}
return NORM_PRIORITY;
}
/**
* Posts the event to the internal Queue of specified priority,
* coalescing as appropriate.
*
* @param theEvent an instance of <code>java.awt.AWTEvent</code>,
* or a subclass of it
* @param priority the desired priority of the event
*/
private void postEvent(AWTEvent theEvent, int priority) {
if (coalesceEvent(theEvent, priority)) {
return;
}
EventQueueItem newItem = new EventQueueItem(theEvent);
cacheEQItem(newItem);
boolean notifyID = (theEvent.getID() == this .waitForID);
if (queues[priority].head == null) {
boolean shouldNotify = noEvents();
queues[priority].head = queues[priority].tail = newItem;
if (shouldNotify) {
if (theEvent.getSource() != AWTAutoShutdown
.getInstance()) {
AWTAutoShutdown.getInstance().notifyThreadBusy(
dispatchThread);
}
notifyAll();
} else if (notifyID) {
notifyAll();
}
} else {
// The event was not coalesced or has non-Component source.
// Insert it at the end of the appropriate Queue.
queues[priority].tail.next = newItem;
queues[priority].tail = newItem;
if (notifyID) {
notifyAll();
}
}
}
private boolean coalescePaintEvent(PaintEvent e) {
ComponentPeer sourcePeer = ((Component) e.getSource()).peer;
if (sourcePeer != null) {
sourcePeer.coalescePaintEvent(e);
}
EventQueueItem[] cache = ((Component) e.getSource()).eventCache;
if (cache == null) {
return false;
}
int index = eventToCacheIndex(e);
if (index != -1 && cache[index] != null) {
PaintEvent merged = mergePaintEvents(e,
(PaintEvent) cache[index].event);
if (merged != null) {
cache[index].event = merged;
return true;
}
}
return false;
}
private PaintEvent mergePaintEvents(PaintEvent a, PaintEvent b) {
Rectangle aRect = a.getUpdateRect();
Rectangle bRect = b.getUpdateRect();
if (bRect.contains(aRect)) {
return b;
}
if (aRect.contains(bRect)) {
return a;
}
return null;
}
private boolean coalesceMouseEvent(MouseEvent e) {
EventQueueItem[] cache = ((Component) e.getSource()).eventCache;
if (cache == null) {
return false;
}
int index = eventToCacheIndex(e);
if (index != -1 && cache[index] != null) {
cache[index].event = e;
return true;
}
return false;
}
private boolean coalescePeerEvent(PeerEvent e) {
EventQueueItem[] cache = ((Component) e.getSource()).eventCache;
if (cache == null) {
return false;
}
int index = eventToCacheIndex(e);
if (index != -1 && cache[index] != null) {
e = e.coalesceEvents((PeerEvent) cache[index].event);
if (e != null) {
cache[index].event = e;
return true;
} else {
cache[index] = null;
}
}
return false;
}
/*
* Should avoid of calling this method by any means
* as it's working time is dependant on EQ length.
* In the wors case this method alone can slow down the entire application
* 10 times by stalling the Event processing.
* Only here by backward compatibility reasons.
*/
private boolean coalesceOtherEvent(AWTEvent e, int priority) {
int id = e.getID();
Component source = (Component) e.getSource();
for (EventQueueItem entry = queues[priority].head; entry != null; entry = entry.next) {
// Give Component.coalesceEvents a chance
if (entry.event.getSource() == source && entry.id == id) {
AWTEvent coalescedEvent = source.coalesceEvents(
entry.event, e);
if (coalescedEvent != null) {
entry.event = coalescedEvent;
return true;
}
}
}
return false;
}
private boolean coalesceEvent(AWTEvent e, int priority) {
if (!(e.getSource() instanceof Component)) {
return false;
}
if (e instanceof PeerEvent) {
return coalescePeerEvent((PeerEvent) e);
}
// The worst case
if (((Component) e.getSource()).isCoalescingEnabled()
&& coalesceOtherEvent(e, priority)) {
return true;
}
if (e instanceof PaintEvent) {
return coalescePaintEvent((PaintEvent) e);
}
if (e instanceof MouseEvent) {
return coalesceMouseEvent((MouseEvent) e);
}
return false;
}
private void cacheEQItem(EventQueueItem entry) {
int index = eventToCacheIndex(entry.event);
if (index != -1 && entry.event.getSource() instanceof Component) {
Component source = (Component) entry.event.getSource();
if (source.eventCache == null) {
source.eventCache = new EventQueueItem[CACHE_LENGTH];
}
source.eventCache[index] = entry;
}
}
private void uncacheEQItem(EventQueueItem entry) {
int index = eventToCacheIndex(entry.event);
if (index != -1 && entry.event.getSource() instanceof Component) {
Component source = (Component) entry.event.getSource();
if (source.eventCache == null) {
return;
}
source.eventCache[index] = null;
}
}
private static final int PAINT = 0;
private static final int UPDATE = 1;
private static final int MOVE = 2;
private static final int DRAG = 3;
private static final int PEER = 4;
private static final int CACHE_LENGTH = 5;
private static int eventToCacheIndex(AWTEvent e) {
switch (e.getID()) {
case PaintEvent.PAINT:
return PAINT;
case PaintEvent.UPDATE:
return UPDATE;
case MouseEvent.MOUSE_MOVED:
return MOVE;
case MouseEvent.MOUSE_DRAGGED:
return DRAG;
default:
return e instanceof PeerEvent ? PEER : -1;
}
}
/**
* Returns whether an event is pending on any of the separate
* Queues.
* @return whether an event is pending on any of the separate Queues
*/
private boolean noEvents() {
for (int i = 0; i < NUM_PRIORITIES; i++) {
if (queues[i].head != null) {
return false;
}
}
return true;
}
/**
* Removes an event from the <code>EventQueue</code> and
* returns it. This method will block until an event has
* been posted by another thread.
* @return the next <code>AWTEvent</code>
* @exception InterruptedException
* if any thread has interrupted this thread
*/
public AWTEvent getNextEvent() throws InterruptedException {
do {
/*
* SunToolkit.flushPendingEvents must be called outside
* of the synchronized block to avoid deadlock when
* event queues are nested with push()/pop().
*/
SunToolkit.flushPendingEvents();
synchronized (this ) {
for (int i = NUM_PRIORITIES - 1; i >= 0; i--) {
if (queues[i].head != null) {
EventQueueItem entry = queues[i].head;
queues[i].head = entry.next;
if (entry.next == null) {
queues[i].tail = null;
}
uncacheEQItem(entry);
return entry.event;
}
}
AWTAutoShutdown.getInstance().notifyThreadFree(
dispatchThread);
wait();
}
} while (true);
}
AWTEvent getNextEvent(int id) throws InterruptedException {
do {
/*
* SunToolkit.flushPendingEvents must be called outside
* of the synchronized block to avoid deadlock when
* event queues are nested with push()/pop().
*/
SunToolkit.flushPendingEvents();
synchronized (this ) {
for (int i = 0; i < NUM_PRIORITIES; i++) {
for (EventQueueItem entry = queues[i].head, prev = null; entry != null; prev = entry, entry = entry.next) {
if (entry.id == id) {
if (prev == null) {
queues[i].head = entry.next;
} else {
prev.next = entry.next;
}
if (queues[i].tail == entry) {
queues[i].tail = prev;
}
uncacheEQItem(entry);
return entry.event;
}
}
}
this .waitForID = id;
wait();
this .waitForID = 0;
}
} while (true);
}
/**
* Returns the first event on the <code>EventQueue</code>
* without removing it.
* @return the first event
*/
public synchronized AWTEvent peekEvent() {
for (int i = NUM_PRIORITIES - 1; i >= 0; i--) {
if (queues[i].head != null) {
return queues[i].head.event;
}
}
return null;
}
/**
* Returns the first event with the specified id, if any.
* @param id the id of the type of event desired
* @return the first event of the specified id or <code>null</code>
* if there is no such event
*/
public synchronized AWTEvent peekEvent(int id) {
for (int i = NUM_PRIORITIES - 1; i >= 0; i--) {
EventQueueItem q = queues[i].head;
for (; q != null; q = q.next) {
if (q.id == id) {
return q.event;
}
}
}
return null;
}
/**
* Dispatches an event. The manner in which the event is
* dispatched depends upon the type of the event and the
* type of the event's source object:
* <p> </p>
* <table border=1 summary="Event types, source types, and dispatch methods">
* <tr>
* <th>Event Type</th>
* <th>Source Type</th>
* <th>Dispatched To</th>
* </tr>
* <tr>
* <td>ActiveEvent</td>
* <td>Any</td>
* <td>event.dispatch()</td>
* </tr>
* <tr>
* <td>Other</td>
* <td>Component</td>
* <td>source.dispatchEvent(AWTEvent)</td>
* </tr>
* <tr>
* <td>Other</td>
* <td>MenuComponent</td>
* <td>source.dispatchEvent(AWTEvent)</td>
* </tr>
* <tr>
* <td>Other</td>
* <td>Other</td>
* <td>No action (ignored)</td>
* </tr>
* </table>
* <p> </p>
* @param event an instance of <code>java.awt.AWTEvent</code>,
* or a subclass of it
* @throws NullPointerException if <code>event</code> is <code>null</code>
* @since 1.2
*/
protected void dispatchEvent(AWTEvent event) {
event.isPosted = true;
Object src = event.getSource();
if (event instanceof ActiveEvent) {
// This could become the sole method of dispatching in time.
setCurrentEventAndMostRecentTimeImpl(event);
((ActiveEvent) event).dispatch();
} else if (src instanceof Component) {
((Component) src).dispatchEvent(event);
event.dispatched();
} else if (src instanceof MenuComponent) {
((MenuComponent) src).dispatchEvent(event);
} else if (src instanceof TrayIcon) {
((TrayIcon) src).dispatchEvent(event);
} else if (src instanceof AWTAutoShutdown) {
if (noEvents()) {
dispatchThread.stopDispatching();
}
} else {
System.err.println("unable to dispatch event: " + event);
}
}
/**
* Returns the timestamp of the most recent event that had a timestamp, and
* that was dispatched from the <code>EventQueue</code> associated with the
* calling thread. If an event with a timestamp is currently being
* dispatched, its timestamp will be returned. If no events have yet
* been dispatched, the EventQueue's initialization time will be
* returned instead.In the current version of
* the JDK, only <code>InputEvent</code>s,
* <code>ActionEvent</code>s, and <code>InvocationEvent</code>s have
* timestamps; however, future versions of the JDK may add timestamps to
* additional event types. Note that this method should only be invoked
* from an application's event dispatching thread. If this method is
* invoked from another thread, the current system time (as reported by
* <code>System.currentTimeMillis()</code>) will be returned instead.
*
* @return the timestamp of the last <code>InputEvent</code>,
* <code>ActionEvent</code>, or <code>InvocationEvent</code> to be
* dispatched, or <code>System.currentTimeMillis()</code> if this
* method is invoked on a thread other than an event dispatching
* thread
* @see java.awt.event.InputEvent#getWhen
* @see java.awt.event.ActionEvent#getWhen
* @see java.awt.event.InvocationEvent#getWhen
*
* @since 1.4
*/
public static long getMostRecentEventTime() {
return Toolkit.getEventQueue().getMostRecentEventTimeImpl();
}
private synchronized long getMostRecentEventTimeImpl() {
return (Thread.currentThread() == dispatchThread) ? mostRecentEventTime
: System.currentTimeMillis();
}
/**
* @return most recent event time on all threads.
*/
synchronized long getMostRecentEventTimeEx() {
return mostRecentEventTime;
}
/**
* Returns the the event currently being dispatched by the
* <code>EventQueue</code> associated with the calling thread. This is
* useful if a method needs access to the event, but was not designed to
* receive a reference to it as an argument. Note that this method should
* only be invoked from an application's event dispatching thread. If this
* method is invoked from another thread, null will be returned.
*
* @return the event currently being dispatched, or null if this method is
* invoked on a thread other than an event dispatching thread
* @since 1.4
*/
public static AWTEvent getCurrentEvent() {
return Toolkit.getEventQueue().getCurrentEventImpl();
}
private synchronized AWTEvent getCurrentEventImpl() {
return (Thread.currentThread() == dispatchThread) ? ((AWTEvent) currentEvent
.get())
: null;
}
/**
* Replaces the existing <code>EventQueue</code> with the specified one.
* Any pending events are transferred to the new <code>EventQueue</code>
* for processing by it.
*
* @param newEventQueue an <code>EventQueue</code>
* (or subclass thereof) instance to be use
* @see java.awt.EventQueue#pop
* @throws NullPointerException if <code>newEventQueue</code> is <code>null</code>
* @since 1.2
*/
public synchronized void push(EventQueue newEventQueue) {
if (debug) {
System.out
.println("EventQueue.push(" + newEventQueue + ")");
}
if (nextQueue != null) {
nextQueue.push(newEventQueue);
return;
}
synchronized (newEventQueue) {
// Transfer all events forward to new EventQueue.
while (peekEvent() != null) {
try {
newEventQueue.postEventPrivate(getNextEvent());
} catch (InterruptedException ie) {
if (debug) {
System.err.println("interrupted push:");
ie.printStackTrace(System.err);
}
}
}
newEventQueue.previousQueue = this ;
}
/*
* Stop the event dispatch thread associated with the currently
* active event queue, so that after the new queue is pushed
* on the top this event dispatch thread won't prevent AWT from
* being automatically shut down.
* Use stopDispatchingLater() to avoid deadlock: stopDispatching()
* waits for the dispatch thread to exit, so if the dispatch
* thread attempts to synchronize on this EventQueue object
* it will never exit since we already hold this lock.
*/
if (dispatchThread != null) {
dispatchThread.stopDispatchingLater();
}
nextQueue = newEventQueue;
AppContext appContext = AppContext.getAppContext();
if (appContext.get(AppContext.EVENT_QUEUE_KEY) == this ) {
appContext.put(AppContext.EVENT_QUEUE_KEY, newEventQueue);
}
}
/**
* Stops dispatching events using this <code>EventQueue</code>.
* Any pending events are transferred to the previous
* <code>EventQueue</code> for processing.
* <p>
* Warning: To avoid deadlock, do not declare this method
* synchronized in a subclass.
*
* @exception EmptyStackException if no previous push was made
* on this <code>EventQueue</code>
* @see java.awt.EventQueue#push
* @since 1.2
*/
protected void pop() throws EmptyStackException {
if (debug) {
System.out.println("EventQueue.pop(" + this + ")");
}
// To prevent deadlock, we lock on the previous EventQueue before
// this one. This uses the same locking order as everything else
// in EventQueue.java, so deadlock isn't possible.
EventQueue prev = previousQueue;
synchronized ((prev != null) ? prev : this ) {
synchronized (this ) {
if (nextQueue != null) {
nextQueue.pop();
return;
}
if (previousQueue == null) {
throw new EmptyStackException();
}
// Transfer all events back to previous EventQueue.
previousQueue.nextQueue = null;
while (peekEvent() != null) {
try {
previousQueue.postEventPrivate(getNextEvent());
} catch (InterruptedException ie) {
if (debug) {
System.err.println("interrupted pop:");
ie.printStackTrace(System.err);
}
}
}
AppContext appContext = AppContext.getAppContext();
if (appContext.get(AppContext.EVENT_QUEUE_KEY) == this ) {
appContext.put(AppContext.EVENT_QUEUE_KEY,
previousQueue);
}
previousQueue = null;
}
}
EventDispatchThread dt = this .dispatchThread;
if (dt != null) {
dt.stopDispatching(); // Must be done outside synchronized
// block to avoid possible deadlock
}
}
/**
* Returns true if the calling thread is the current AWT
* <code>EventQueue</code>'s dispatch thread. Use this
* call the ensure that a given
* task is being executed (or not being) on the current AWT
* <code>EventDispatchThread</code>.
*
* @return true if running on the current AWT
* <code>EventQueue</code>'s dispatch thread
* @since 1.2
*/
public static boolean isDispatchThread() {
EventQueue eq = Toolkit.getEventQueue();
EventQueue next = eq.nextQueue;
while (next != null) {
eq = next;
next = eq.nextQueue;
}
return (Thread.currentThread() == eq.dispatchThread);
}
final void initDispatchThread() {
synchronized (this ) {
if (dispatchThread == null && !threadGroup.isDestroyed()) {
dispatchThread = (EventDispatchThread) AccessController
.doPrivileged(new PrivilegedAction() {
public Object run() {
EventDispatchThread t = new EventDispatchThread(
threadGroup, name,
EventQueue.this );
t.setContextClassLoader(classLoader);
t.setPriority(Thread.NORM_PRIORITY + 1);
t.setDaemon(false);
return t;
}
});
AWTAutoShutdown.getInstance().notifyThreadBusy(
dispatchThread);
dispatchThread.start();
}
}
}
final void detachDispatchThread() {
dispatchThread = null;
}
/*
* Gets the <code>EventDispatchThread</code> for this
* <code>EventQueue</code>.
* @return the event dispatch thread associated with this event queue
* or <code>null</code> if this event queue doesn't have a
* working thread associated with it
* @see java.awt.EventQueue#initDispatchThread
* @see java.awt.EventQueue#detachDispatchThread
*/
final EventDispatchThread getDispatchThread() {
return dispatchThread;
}
/*
* Removes any pending events for the specified source object.
* If removeAllEvents parameter is <code>true</code> then all
* events for the specified source object are removed, if it
* is <code>false</code> then <code>SequencedEvent</code>, <code>SentEvent</code>,
* <code>FocusEvent</code>, <code>WindowEvent</code>, <code>KeyEvent</code>,
* and <code>InputMethodEvent</code> are kept in the queue, but all other
* events are removed.
*
* This method is normally called by the source's
* <code>removeNotify</code> method.
*/
final void removeSourceEvents(Object source, boolean removeAllEvents) {
SunToolkit.flushPendingEvents();
synchronized (this ) {
for (int i = 0; i < NUM_PRIORITIES; i++) {
EventQueueItem entry = queues[i].head;
EventQueueItem prev = null;
while (entry != null) {
if ((entry.event.getSource() == source)
&& (removeAllEvents || !(entry.event instanceof SequencedEvent
|| entry.event instanceof SentEvent
|| entry.event instanceof FocusEvent
|| entry.event instanceof WindowEvent
|| entry.event instanceof KeyEvent || entry.event instanceof InputMethodEvent))) {
if (entry.event instanceof SequencedEvent) {
((SequencedEvent) entry.event).dispose();
}
if (entry.event instanceof SentEvent) {
((SentEvent) entry.event).dispose();
}
if (prev == null) {
queues[i].head = entry.next;
} else {
prev.next = entry.next;
}
uncacheEQItem(entry);
} else {
prev = entry;
}
entry = entry.next;
}
queues[i].tail = prev;
}
}
}
static void setCurrentEventAndMostRecentTime(AWTEvent e) {
Toolkit.getEventQueue().setCurrentEventAndMostRecentTimeImpl(e);
}
private synchronized void setCurrentEventAndMostRecentTimeImpl(
AWTEvent e) {
if (Thread.currentThread() != dispatchThread) {
return;
}
currentEvent = new WeakReference(e);
// This series of 'instanceof' checks should be replaced with a
// polymorphic type (for example, an interface which declares a
// getWhen() method). However, this would require us to make such
// a type public, or to place it in sun.awt. Both of these approaches
// have been frowned upon. So for now, we hack.
//
// In tiger, we will probably give timestamps to all events, so this
// will no longer be an issue.
long mostRecentEventTime2 = Long.MIN_VALUE;
if (e instanceof InputEvent) {
InputEvent ie = (InputEvent) e;
mostRecentEventTime2 = ie.getWhen();
} else if (e instanceof InputMethodEvent) {
InputMethodEvent ime = (InputMethodEvent) e;
mostRecentEventTime2 = ime.getWhen();
} else if (e instanceof ActionEvent) {
ActionEvent ae = (ActionEvent) e;
mostRecentEventTime2 = ae.getWhen();
} else if (e instanceof InvocationEvent) {
InvocationEvent ie = (InvocationEvent) e;
mostRecentEventTime2 = ie.getWhen();
}
mostRecentEventTime = Math.max(mostRecentEventTime,
mostRecentEventTime2);
}
/**
* Causes <code>runnable</code> to have its <code>run</code>
* method called in the dispatch thread of
* {@link Toolkit#getSystemEventQueue the system EventQueue}.
* This will happen after all pending events are processed.
*
* @param runnable the <code>Runnable</code> whose <code>run</code>
* method should be executed
* synchronously on the <code>EventQueue</code>
* @see #invokeAndWait
* @since 1.2
*/
public static void invokeLater(Runnable runnable) {
Toolkit.getEventQueue().postEvent(
new InvocationEvent(Toolkit.getDefaultToolkit(),
runnable));
}
/**
* Causes <code>runnable</code> to have its <code>run</code>
* method called in the dispatch thread of
* {@link Toolkit#getSystemEventQueue the system EventQueue}.
* This will happen after all pending events are processed.
* The call blocks until this has happened. This method
* will throw an Error if called from the event dispatcher thread.
*
* @param runnable the <code>Runnable</code> whose <code>run</code>
* method should be executed
* synchronously on the <code>EventQueue</code>
* @exception InterruptedException if any thread has
* interrupted this thread
* @exception InvocationTargetException if an throwable is thrown
* when running <code>runnable</code>
* @see #invokeLater
* @since 1.2
*/
public static void invokeAndWait(Runnable runnable)
throws InterruptedException, InvocationTargetException {
if (EventQueue.isDispatchThread()) {
throw new Error(
"Cannot call invokeAndWait from the event dispatcher thread");
}
class AWTInvocationLock {
}
Object lock = new AWTInvocationLock();
InvocationEvent event = new InvocationEvent(Toolkit
.getDefaultToolkit(), runnable, lock, true);
synchronized (lock) {
Toolkit.getEventQueue().postEvent(event);
lock.wait();
}
Throwable eventThrowable = event.getThrowable();
if (eventThrowable != null) {
throw new InvocationTargetException(eventThrowable);
}
}
/*
* Called from PostEventQueue.postEvent to notify that a new event
* appeared. First it proceeds to the EventQueue on the top of the
* stack, then notifies the associated dispatch thread if it exists
* or starts a new one otherwise.
*/
private void wakeup(boolean isShutdown) {
synchronized (this ) {
if (nextQueue != null) {
// Forward call to the top of EventQueue stack.
nextQueue.wakeup(isShutdown);
} else if (dispatchThread != null) {
notifyAll();
} else if (!isShutdown) {
initDispatchThread();
}
}
}
}
/**
* The Queue object holds pointers to the beginning and end of one internal
* queue. An EventQueue object is composed of multiple internal Queues, one
* for each priority supported by the EventQueue. All Events on a particular
* internal Queue have identical priority.
*/
class Queue {
EventQueueItem head;
EventQueueItem tail;
}
class EventQueueItem {
AWTEvent event;
int id;
EventQueueItem next;
EventQueueItem(AWTEvent evt) {
event = evt;
id = evt.getID();
}
}
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