EventQueue is a platform-independent class
* that queues events, both from the underlying peer classes
* and from trusted application classes.
*
* 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 EventQueue 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 EventQueue can be coalesced)
* are dispatched:
*
AWTEvent A is enqueued
* to the EventQueue before
* AWTEvent B then event B will not be
* dispatched before event A.
*
* 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 EventQueue
* per context. Other browsers place all applets into the same
* context, implying that there will be only a single, global
* EventQueue for all applets. This behavior is
* implementation-dependent. Consult your browser's documentation
* for more information.
*
* For information on the threading issues of the event dispatch
* machinery, see AWT Threading Issues.
*
* @author Thomas Ball
* @author Fred Ecks
* @author David Mendenhall
*
* @since 1.1
*/
public class EventQueue {
private static final AtomicInteger threadInitNumber = new AtomicInteger(0);
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;
/*
* A single lock to synchronize the push()/pop() and related operations with
* all the EventQueues from the AppContext. Synchronization on any particular
* event queue(s) is not enough: we should lock the whole stack.
*/
private final Lock pushPopLock;
private final Condition pushPopCond;
/*
* Dummy runnable to wake up EDT from getNextEvent() after
push/pop is performed
*/
private final static Runnable dummyRunnable = new Runnable() {
public void run() {
}
};
private EventDispatchThread dispatchThread;
private final ThreadGroup threadGroup =
Thread.currentThread().getThreadGroup();
private final ClassLoader classLoader =
Thread.currentThread().getContextClassLoader();
/*
* 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 volatile int waitForID;
private final String name = "AWT-EventQueue-" + threadInitNumber.getAndIncrement();
private static final PlatformLogger eventLog = PlatformLogger.getLogger("java.awt.event.EventQueue");
static {
AWTAccessor.setEventQueueAccessor(
new AWTAccessor.EventQueueAccessor() {
public Thread getDispatchThread(EventQueue eventQueue) {
return eventQueue.getDispatchThread();
}
public boolean isDispatchThreadImpl(EventQueue eventQueue) {
return eventQueue.isDispatchThreadImpl();
}
});
}
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.
*/
pushPopLock = (Lock)AppContext.getAppContext().get(AppContext.EVENT_QUEUE_LOCK_KEY);
pushPopCond = (Condition)AppContext.getAppContext().get(AppContext.EVENT_QUEUE_COND_KEY);
}
/**
* Posts a 1.1-style event to the EventQueue.
* If there is an existing event on the queue with the same ID
* and event source, the source Component's
* coalesceEvents method will be called.
*
* @param theEvent an instance of java.awt.AWTEvent,
* or a subclass of it
* @throws NullPointerException if theEvent is null
*/
public void postEvent(AWTEvent theEvent) {
SunToolkit.flushPendingEvents();
postEventPrivate(theEvent);
}
/**
* Posts a 1.1-style event to the EventQueue.
* If there is an existing event on the queue with the same ID
* and event source, the source Component's
* coalesceEvents method will be called.
*
* @param theEvent an instance of java.awt.AWTEvent,
* or a subclass of it
*/
private final void postEventPrivate(AWTEvent theEvent) {
theEvent.isPosted = true;
pushPopLock.lock();
try {
if (nextQueue != null) {
// Forward the event to the top of EventQueue stack
nextQueue.postEventPrivate(theEvent);
return;
}
if (dispatchThread == null) {
if (theEvent.getSource() == AWTAutoShutdown.getInstance()) {
return;
} else {
initDispatchThread();
}
}
postEvent(theEvent, getPriority(theEvent));
} finally {
pushPopLock.unlock();
}
}
private static int getPriority(AWTEvent theEvent) {
if (theEvent instanceof PeerEvent) {
PeerEvent peerEvent = (PeerEvent)theEvent;
if ((peerEvent.getFlags() & PeerEvent.ULTIMATE_PRIORITY_EVENT) != 0) {
return ULTIMATE_PRIORITY;
}
if ((peerEvent.getFlags() & PeerEvent.PRIORITY_EVENT) != 0) {
return HIGH_PRIORITY;
}
if ((peerEvent.getFlags() & PeerEvent.LOW_PRIORITY_EVENT) != 0) {
return LOW_PRIORITY;
}
}
int id = theEvent.getID();
if ((id >= PaintEvent.PAINT_FIRST) && (id <= PaintEvent.PAINT_LAST)) {
return LOW_PRIORITY;
}
return NORM_PRIORITY;
}
/**
* Posts the event to the internal Queue of specified priority,
* coalescing as appropriate.
*
* @param theEvent an instance of java.awt.AWTEvent,
* 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);
}
pushPopCond.signalAll();
} else if (notifyID) {
pushPopCond.signalAll();
}
} 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) {
pushPopCond.signalAll();
}
}
}
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.event.getID() == 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 EventQueue and
* returns it. This method will block until an event has
* been posted by another thread.
* @return the next AWTEvent
* @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();
pushPopLock.lock();
try {
AWTEvent event = getNextEventPrivate();
if (event != null) {
return event;
}
AWTAutoShutdown.getInstance().notifyThreadFree(dispatchThread);
pushPopCond.await();
} finally {
pushPopLock.unlock();
}
} while(true);
}
/*
* Must be called under the lock. Doesn't call flushPendingEvents()
*/
AWTEvent getNextEventPrivate() throws InterruptedException {
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;
}
}
return null;
}
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();
pushPopLock.lock();
try {
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.event.getID() == 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;
}
}
}
waitForID = id;
pushPopCond.await();
waitForID = 0;
} finally {
pushPopLock.unlock();
}
} while(true);
}
/**
* Returns the first event on the EventQueue
* without removing it.
* @return the first event
*/
public AWTEvent peekEvent() {
pushPopLock.lock();
try {
for (int i = NUM_PRIORITIES - 1; i >= 0; i--) {
if (queues[i].head != null) {
return queues[i].head.event;
}
}
} finally {
pushPopLock.unlock();
}
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 null
* if there is no such event
*/
public AWTEvent peekEvent(int id) {
pushPopLock.lock();
try {
for (int i = NUM_PRIORITIES - 1; i >= 0; i--) {
EventQueueItem q = queues[i].head;
for (; q != null; q = q.next) {
if (q.event.getID() == id) {
return q.event;
}
}
}
} finally {
pushPopLock.unlock();
}
return null;
}
private static final JavaSecurityAccess javaSecurityAccess =
SharedSecrets.getJavaSecurityAccess();
/**
* 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:
*
*
| Event Type | *Source Type | *Dispatched To | *
|---|---|---|
| ActiveEvent | *Any | *event.dispatch() | *
| Other | *Component | *source.dispatchEvent(AWTEvent) | *
| Other | *MenuComponent | *source.dispatchEvent(AWTEvent) | *
| Other | *Other | *No action (ignored) | *
* @param event an instance of
java.awt.AWTEvent,
* or a subclass of it
* @throws NullPointerException if event is null
* @since 1.2
*/
protected void dispatchEvent(final AWTEvent event) {
final Object src = event.getSource();
final PrivilegedActionEventQueue 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 InputEvents,
* ActionEvents, and InvocationEvents 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 {@link #isDispatchThread event dispatching thread}.
* If this method is
* invoked from another thread, the current system time (as reported by
* System.currentTimeMillis()) will be returned instead.
*
* @return the timestamp of the last InputEvent,
* ActionEvent, or InvocationEvent to be
* dispatched, or System.currentTimeMillis() 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
* @see #isDispatchThread
*
* @since 1.4
*/
public static long getMostRecentEventTime() {
return Toolkit.getEventQueue().getMostRecentEventTimeImpl();
}
private long getMostRecentEventTimeImpl() {
pushPopLock.lock();
try {
return (Thread.currentThread() == dispatchThread)
? mostRecentEventTime
: System.currentTimeMillis();
} finally {
pushPopLock.unlock();
}
}
/**
* @return most recent event time on all threads.
*/
long getMostRecentEventTimeEx() {
pushPopLock.lock();
try {
return mostRecentEventTime;
} finally {
pushPopLock.unlock();
}
}
/**
* Returns the the event currently being dispatched by the
* EventQueue 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 AWTEvent getCurrentEventImpl() {
pushPopLock.lock();
try {
return (Thread.currentThread() == dispatchThread)
? ((AWTEvent)currentEvent.get())
: null;
} finally {
pushPopLock.unlock();
}
}
/**
* Replaces the existing EventQueue with the specified one.
* Any pending events are transferred to the new EventQueue
* for processing by it.
*
* @param newEventQueue an EventQueue
* (or subclass thereof) instance to be use
* @see java.awt.EventQueue#pop
* @throws NullPointerException if newEventQueue is null
* @since 1.2
*/
public void push(EventQueue newEventQueue) {
if (eventLog.isLoggable(PlatformLogger.FINE)) {
eventLog.fine("EventQueue.push(" + newEventQueue + ")");
}
pushPopLock.lock();
try {
EventQueue topQueue = this;
while (topQueue.nextQueue != null) {
topQueue = topQueue.nextQueue;
}
if ((topQueue.dispatchThread != null) &&
(topQueue.dispatchThread.getEventQueue() == this))
{
newEventQueue.dispatchThread = topQueue.dispatchThread;
topQueue.dispatchThread.setEventQueue(newEventQueue);
}
// Transfer all events forward to new EventQueue.
while (topQueue.peekEvent() != null) {
try {
// Use getNextEventPrivate() as it doesn't call flushPendingEvents()
newEventQueue.postEventPrivate(topQueue.getNextEventPrivate());
} catch (InterruptedException ie) {
if (eventLog.isLoggable(PlatformLogger.FINE)) {
eventLog.fine("Interrupted push", ie);
}
}
}
// Wake up EDT waiting in getNextEvent(), so it can
// pick up a new EventQueue. Post the waking event before
// topQueue.nextQueue is assigned, otherwise the event would
// go newEventQueue
topQueue.postEventPrivate(new InvocationEvent(topQueue, dummyRunnable));
newEventQueue.previousQueue = topQueue;
topQueue.nextQueue = newEventQueue;
AppContext appContext = AppContext.getAppContext();
if (appContext.get(AppContext.EVENT_QUEUE_KEY) == topQueue) {
appContext.put(AppContext.EVENT_QUEUE_KEY, newEventQueue);
}
pushPopCond.signalAll();
} finally {
pushPopLock.unlock();
}
}
/**
* Stops dispatching events using this EventQueue.
* Any pending events are transferred to the previous
* EventQueue for processing.
*
* Warning: To avoid deadlock, do not declare this method
* synchronized in a subclass.
*
* @exception EmptyStackException if no previous push was made
* on this EventQueue
* @see java.awt.EventQueue#push
* @since 1.2
*/
protected void pop() throws EmptyStackException {
if (eventLog.isLoggable(PlatformLogger.FINE)) {
eventLog.fine("EventQueue.pop(" + this + ")");
}
pushPopLock.lock();
try {
EventQueue topQueue = this;
while (topQueue.nextQueue != null) {
topQueue = topQueue.nextQueue;
}
EventQueue prevQueue = topQueue.previousQueue;
if (prevQueue == null) {
throw new EmptyStackException();
}
topQueue.previousQueue = null;
prevQueue.nextQueue = null;
// Transfer all events back to previous EventQueue.
while (topQueue.peekEvent() != null) {
try {
prevQueue.postEventPrivate(topQueue.getNextEventPrivate());
} catch (InterruptedException ie) {
if (eventLog.isLoggable(PlatformLogger.FINE)) {
eventLog.fine("Interrupted pop", ie);
}
}
}
if ((topQueue.dispatchThread != null) &&
(topQueue.dispatchThread.getEventQueue() == this))
{
prevQueue.dispatchThread = topQueue.dispatchThread;
topQueue.dispatchThread.setEventQueue(prevQueue);
}
AppContext appContext = AppContext.getAppContext();
if (appContext.get(AppContext.EVENT_QUEUE_KEY) == this) {
appContext.put(AppContext.EVENT_QUEUE_KEY, prevQueue);
}
// Wake up EDT waiting in getNextEvent(), so it can
// pick up a new EventQueue
topQueue.postEventPrivate(new InvocationEvent(topQueue, dummyRunnable));
pushPopCond.signalAll();
} finally {
pushPopLock.unlock();
}
}
/**
* Creates a new {@code secondary loop} associated with this
* event queue. Use the {@link SecondaryLoop#enter} and
* {@link SecondaryLoop#exit} methods to start and stop the
* event loop and dispatch the events from this queue.
*
* @return secondaryLoop A new secondary loop object, which can
* be used to launch a new nested event
* loop and dispatch events from this queue
*
* @see SecondaryLoop#enter
* @see SecondaryLoop#exit
*
* @since 1.7
*/
public SecondaryLoop createSecondaryLoop() {
return createSecondaryLoop(null, null, 0);
}
SecondaryLoop createSecondaryLoop(Conditional cond, EventFilter filter, long interval) {
pushPopLock.lock();
try {
if (nextQueue != null) {
// Forward the request to the top of EventQueue stack
return nextQueue.createSecondaryLoop(cond, filter, interval);
}
if (dispatchThread == null) {
initDispatchThread();
}
return new WaitDispatchSupport(dispatchThread, cond, filter, interval);
} finally {
pushPopLock.unlock();
}
}
/**
* Returns true if the calling thread is
* {@link Toolkit#getSystemEventQueue the current AWT EventQueue}'s
* dispatch thread. Use this method to ensure that a particular
* task is being executed (or not being) there.
*
* Note: use the {@link #invokeLater} or {@link #invokeAndWait} * methods to execute a task in * {@link Toolkit#getSystemEventQueue the current AWT EventQueue}'s * dispatch thread. *
*
* @return true if running in
* {@link Toolkit#getSystemEventQueue the current AWT EventQueue}'s
* dispatch thread
* @see #invokeLater
* @see #invokeAndWait
* @see Toolkit#getSystemEventQueue
* @since 1.2
*/
public static boolean isDispatchThread() {
EventQueue eq = Toolkit.getEventQueue();
return eq.isDispatchThreadImpl();
}
final boolean isDispatchThreadImpl() {
EventQueue eq = this;
pushPopLock.lock();
try {
EventQueue next = eq.nextQueue;
while (next != null) {
eq = next;
next = eq.nextQueue;
}
return (Thread.currentThread() == eq.dispatchThread);
} finally {
pushPopLock.unlock();
}
}
final void initDispatchThread() {
pushPopLock.lock();
try {
AppContext appContext = AppContext.getAppContext();
if (dispatchThread == null && !threadGroup.isDestroyed() && !appContext.isDisposed()) {
dispatchThread = AccessController.doPrivileged(
new PrivilegedActionEventDispatchThread for this
* EventQueue.
* @return the event dispatch thread associated with this event queue
* or null 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() {
pushPopLock.lock();
try {
return dispatchThread;
} finally {
pushPopLock.unlock();
}
}
/*
* Removes any pending events for the specified source object.
* If removeAllEvents parameter is true then all
* events for the specified source object are removed, if it
* is false then SequencedEvent, SentEvent,
* FocusEvent, WindowEvent, KeyEvent,
* and InputMethodEvent are kept in the queue, but all other
* events are removed.
*
* This method is normally called by the source's
* removeNotify method.
*/
final void removeSourceEvents(Object source, boolean removeAllEvents) {
SunToolkit.flushPendingEvents();
pushPopLock.lock();
try {
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;
}
} finally {
pushPopLock.unlock();
}
}
static void setCurrentEventAndMostRecentTime(AWTEvent e) {
Toolkit.getEventQueue().setCurrentEventAndMostRecentTimeImpl(e);
}
private void setCurrentEventAndMostRecentTimeImpl(AWTEvent e) {
pushPopLock.lock();
try {
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);
} finally {
pushPopLock.unlock();
}
}
/**
* Causes runnable to have its run
* method called in the {@link #isDispatchThread dispatch thread} of
* {@link Toolkit#getSystemEventQueue the system EventQueue}.
* This will happen after all pending events are processed.
*
* @param runnable the Runnable whose run
* method should be executed
* asynchronously in the
* {@link #isDispatchThread event dispatch thread}
* of {@link Toolkit#getSystemEventQueue the system EventQueue}
* @see #invokeAndWait
* @see Toolkit#getSystemEventQueue
* @see #isDispatchThread
* @since 1.2
*/
public static void invokeLater(Runnable runnable) {
Toolkit.getEventQueue().postEvent(
new InvocationEvent(Toolkit.getDefaultToolkit(), runnable));
}
/**
* Causes runnable to have its run
* method called in the {@link #isDispatchThread 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
* {@link #isDispatchThread event dispatcher thread}.
*
* @param runnable the Runnable whose run
* method should be executed
* synchronously in the
* {@link #isDispatchThread event dispatch thread}
* of {@link Toolkit#getSystemEventQueue the system EventQueue}
* @exception InterruptedException if any thread has
* interrupted this thread
* @exception InvocationTargetException if an throwable is thrown
* when running runnable
* @see #invokeLater
* @see Toolkit#getSystemEventQueue
* @see #isDispatchThread
* @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);
while (!event.isDispatched()) {
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) {
pushPopLock.lock();
try {
if (nextQueue != null) {
// Forward call to the top of EventQueue stack.
nextQueue.wakeup(isShutdown);
} else if (dispatchThread != null) {
pushPopCond.signalAll();
} else if (!isShutdown) {
initDispatchThread();
}
} finally {
pushPopLock.unlock();
}
}
}
/**
* 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;
}