Artifact
6297c9ee3f353aa14516b53f0b2bb3d7892734e9:
/*
* TclEvent.java --
*
* Abstract class for describing an event in the Tcl notifier
* API.
*
* Copyright (c) 1997 Cornell University.
* Copyright (c) 1997 Sun Microsystems, Inc.
*
* See the file "license.terms" for information on usage and
* redistribution of this file, and for a DISCLAIMER OF ALL
* WARRANTIES.
*
* RCS: @(#) $Id: TclEvent.java,v 1.3 2003/03/11 01:45:53 mdejong Exp $
*
*/
package tcl.lang;
/*
* This is an abstract class that describes an event in the Jacl
* implementation of the notifier. It contains package protected
* fields and methods that are accessed by the Jacl notifier. Tcl Blend
* needs a different implementation of the TclEvent base class.
*
* The only public methods in this class are processEvent() and
* sync(). These methods must appear in both the Jacl and Tcl Blend versions
* of this class.
*/
public abstract class TclEvent {
/*
* The notifier in which this event is queued.
*/
Notifier notifier = null;
/*
* This flag is true if sync() has been called on this object.
*/
boolean needsNotify = false;
/*
* True if this event is current being processing. This flag provents
* an event to be processed twice when the event loop is entered
* recursively.
*/
boolean isProcessing = false;
/*
* True if this event has been processed.
*/
boolean isProcessed = false;
/*
* Links to the next event in the event queue.
*/
TclEvent next;
/*
*----------------------------------------------------------------------
*
* processEvent --
*
* Process the event. Override this method to implement new types
* of events.
*
* Note: this method is called by the primary thread of the
* notifier.
*
* Results:
* 1 means the event has been processed and can be removed from
* the event queue. 0 means the event should be deferred for
* processing later.
*
* Side effects:
* This method may have arbitrary side effects while processing
* the event.
*
*----------------------------------------------------------------------
*/
public abstract int
processEvent(
int flags); // Same as flags passed to Notifier.doOneEvent.
/*
*----------------------------------------------------------------------
*
* sync --
*
* Wait until the event is processed.
*
* Results:
* None.
*
* Side effects:
* Arbitrary things may happen while this thread is waiting.
*
*----------------------------------------------------------------------
*/
public final void
sync()
{
if (notifier == null) {
throw new TclRuntimeError(
"TclEvent is not queued when sync() is called");
}
if (Thread.currentThread() == notifier.primaryThread) {
while (!isProcessed) {
notifier.serviceEvent(0);
}
} else {
synchronized (this) {
needsNotify = true;
while (!isProcessed) {
try {
wait(0);
} catch (InterruptedException e) {
// Another thread has sent us an "interrupt"
// signal. We ignore it and continue waiting until
// the event is processed.
continue;
}
}
}
}
}
} // end TclEvent