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| java.lang.Object
 java.awt.EventQueue
| EventQueue | | public class EventQueue (Code) | | 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
EventQueue.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:
- Sequentially.
- That is, it is not permitted that several events from
this queue are dispatched simultaneously.
- In the same order as they are enqueued.
- That is, if
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
version:
1.114, 06/05/07
since:
1.1 |
| EventQueue | | public EventQueue()(Code) | | |
| detachDispatchThread | | final void detachDispatchThread()(Code) | | |
| dispatchEvent | | protected void dispatchEvent(AWTEvent event)(Code) | | 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) |
Parameters:
event - an instance of java.awt.AWTEvent,or a subclass of it
throws:
NullPointerException - if event is null
since:
1.2 |
| getCurrentEvent | | public static AWTEvent getCurrentEvent()(Code) | | 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.
the event currently being dispatched, or null if this method isinvoked on a thread other than an event dispatching thread
since:
1.4 |
| getMostRecentEventTime | | public static long getMostRecentEventTime()(Code) | | Returns the timestamp of the most recent event that had a timestamp, and
that was dispatched from the EventQueue 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 event dispatching thread. If this method is
invoked from another thread, the current system time (as reported by
System.currentTimeMillis()) will be returned instead.
the timestamp of the last InputEvent,ActionEvent, or InvocationEvent to bedispatched, or System.currentTimeMillis() if thismethod is invoked on a thread other than an event dispatchingthread
See Also: java.awt.event.InputEvent.getWhen
See Also: java.awt.event.ActionEvent.getWhen
See Also: java.awt.event.InvocationEvent.getWhen
since:
1.4 |
| getMostRecentEventTimeEx | | synchronized long getMostRecentEventTimeEx()(Code) | | most recent event time on all threads. |
| getNextEvent | | public AWTEvent getNextEvent() throws InterruptedException(Code) | | Removes an event from the EventQueue and
returns it. This method will block until an event has
been posted by another thread.
the next AWTEvent
exception:
InterruptedException - if any thread has interrupted this thread |
| initDispatchThread | | final void initDispatchThread()(Code) | | |
| invokeLater | | public static void invokeLater(Runnable runnable)(Code) | | Causes runnable to have its run
method called in the dispatch thread of
Toolkit.getSystemEventQueue the system EventQueue .
This will happen after all pending events are processed.
Parameters:
runnable - the Runnable whose runmethod should be executedsynchronously on the EventQueue
See Also: EventQueue.invokeAndWait
since:
1.2 |
| isDispatchThread | | public static boolean isDispatchThread()(Code) | | Returns true if the calling thread is the current AWT
EventQueue's dispatch thread. Use this
call the ensure that a given
task is being executed (or not being) on the current AWT
EventDispatchThread.
true if running on the current AWTEventQueue's dispatch thread
since:
1.2 |
| peekEvent | | public synchronized AWTEvent peekEvent()(Code) | | Returns the first event on the EventQueue
without removing it.
the first event |
| peekEvent | | public synchronized AWTEvent peekEvent(int id)(Code) | | Returns the first event with the specified id, if any.
Parameters:
id - the id of the type of event desired the first event of the specified id or nullif there is no such event |
| pop | | protected void pop() throws EmptyStackException(Code) | | 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 madeon this EventQueue
See Also: java.awt.EventQueue.push
since:
1.2 |
| postEvent | | public void postEvent(AWTEvent theEvent)(Code) | | 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.
Parameters:
theEvent - an instance of java.awt.AWTEvent,or a subclass of it
throws:
NullPointerException - if theEvent is null |
| postEventPrivate | | final void postEventPrivate(AWTEvent theEvent)(Code) | | 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.
Parameters:
theEvent - an instance of java.awt.AWTEvent,or a subclass of it |
| push | | public synchronized void push(EventQueue newEventQueue)(Code) | | Replaces the existing EventQueue with the specified one.
Any pending events are transferred to the new EventQueue
for processing by it.
Parameters:
newEventQueue - an EventQueue(or subclass thereof) instance to be use
See Also: java.awt.EventQueue.pop
throws:
NullPointerException - if newEventQueue is null
since:
1.2 |
| removeSourceEvents | | final void removeSourceEvents(Object source, boolean removeAllEvents)(Code) | | |
| setCurrentEventAndMostRecentTime | | static void setCurrentEventAndMostRecentTime(AWTEvent e)(Code) | | |
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