diff options
Diffstat (limited to 'libjava/java/awt/EventQueue.java')
| -rw-r--r-- | libjava/java/awt/EventQueue.java | 121 |
1 files changed, 89 insertions, 32 deletions
diff --git a/libjava/java/awt/EventQueue.java b/libjava/java/awt/EventQueue.java index 7037118..a47d34f 100644 --- a/libjava/java/awt/EventQueue.java +++ b/libjava/java/awt/EventQueue.java @@ -1,10 +1,28 @@ -/* Copyright (C) 2000, 2001 Free Software Foundation +/* Copyright (C) 1999, 2000, 2001, 2002 Free Software Foundation - This file is part of libgcj. +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath 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 for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA +02111-1307 USA. + +As a special exception, if you link this library with other files to +produce an executable, this library does not by itself cause the +resulting executable to be covered by the GNU General Public License. +This exception does not however invalidate any other reasons why the +executable file might be covered by the GNU General Public License. */ -This software is copyrighted work licensed under the terms of the -Libgcj License. Please consult the file "LIBGCJ_LICENSE" for -details. */ package java.awt; @@ -18,13 +36,19 @@ import java.lang.reflect.InvocationTargetException; * Status: Believed complete, but untested. Check FIXME's. */ -/** @author Bryce McKinlay */ - +/** + * This class manages a queue of <code>AWTEvent</code> objects that + * are posted to it. The AWT system uses only one event queue for all + * events. + * + * @author Bryce McKinlay + * @author Aaron M. Renn (arenn@urbanophile.com) + */ public class EventQueue { private static final int INITIAL_QUEUE_DEPTH = 8; private AWTEvent[] queue = new AWTEvent[INITIAL_QUEUE_DEPTH]; - + private int next_in = 0; // Index where next event will be added to queue private int next_out = 0; // Index of next event to be removed from queue @@ -33,40 +57,68 @@ public class EventQueue private EventDispatchThread dispatchThread = new EventDispatchThread(this); + /** + * Initializes a new instance of <code>EventQueue</code>. + */ public EventQueue() { } - + + /** + * Returns the next event in the queue. This method will block until + * an event is available or until the thread is interrupted. + * + * @return The next event in the queue. + * + * @exception InterruptedException If this thread is interrupted while + * waiting for an event to be posted to the queue. + */ public synchronized AWTEvent getNextEvent() throws InterruptedException { if (next != null) return next.getNextEvent(); - + while (next_in == next_out) wait(); - + AWTEvent res = queue[next_out]; - + if (++next_out == queue.length) next_out = 0; return res; } - - /** @specnote Does not block. Returns null if there are no events on the + + /** + * Returns the next event in the queue without removing it from the queue. + * This method will block until an event is available or until the thread + * is interrupted. + * + * @return The next event in the queue. + * @specnote Does not block. Returns null if there are no events on the * queue. */ public synchronized AWTEvent peekEvent() { if (next != null) return next.peekEvent(); - + if (next_in != next_out) return queue[next_out]; else return null; } - - /** @specnote Does not block. Returns null if there are no matching events + + /** + * Returns the next event in the queue that has the specified id + * without removing it from the queue. + * This method will block until an event is available or until the thread + * is interrupted. + * + * @param id The event id to return. + * + * @return The next event in the queue. + * + * @specnote Does not block. Returns null if there are no matching events * on the queue. */ public synchronized AWTEvent peekEvent(int id) @@ -83,7 +135,12 @@ public class EventQueue } return null; } - + + /** + * Posts a new event to the queue. + * + * @param event The event to post to the queue. + */ public synchronized void postEvent(AWTEvent evt) { if (next != null) @@ -92,7 +149,7 @@ public class EventQueue return; } // FIXME: Security checks? - + /* Check for any events already on the queue with the same source and ID. */ int i = next_out; @@ -123,24 +180,24 @@ public class EventQueue queue[next_in] = evt; if (++next_in == queue.length) next_in = 0; - + if (next_in == next_out) { /* Queue is full. Extend it. */ AWTEvent[] oldQueue = queue; queue = new AWTEvent[queue.length * 2]; - + int len = oldQueue.length - next_out; System.arraycopy(oldQueue, next_out, queue, 0, len); if (next_out != 0) System.arraycopy(oldQueue, 0, queue, len, next_out); - + next_out = 0; next_in = oldQueue.length; } notify(); } - + /** @since JDK1.2 */ public static void invokeAndWait(Runnable runnable) throws InterruptedException, InvocationTargetException @@ -149,7 +206,7 @@ public class EventQueue Thread current = Thread.currentThread(); if (current == eq.dispatchThread) throw new Error("Can't call invokeAndWait from event dispatch thread"); - + InvocationEvent ie = new InvocationEvent(eq, runnable, current, true); @@ -160,11 +217,11 @@ public class EventQueue } Exception exception; - + if ((exception = ie.getException()) != null) throw new InvocationTargetException(exception); } - + /** @since JDK1.2 */ public static void invokeLater(Runnable runnable) { @@ -175,13 +232,13 @@ public class EventQueue eq.postEvent(ie); } - + public static boolean isDispatchThread() { EventQueue eq = Toolkit.getDefaultToolkit().getSystemEventQueue(); return (Thread.currentThread() == eq.dispatchThread); } - + /** Allows a custom EventQueue implementation to replace this one. * All pending events are transferred to the new queue. Calls to postEvent, * getNextEvent, and peekEvent are forwarded to the pushed queue until it @@ -201,21 +258,21 @@ public class EventQueue next = newEventQueue; newEventQueue.prev = this; } - + /** Transfer any pending events from this queue back to the parent queue that * was previously push()ed. Event dispatch from this queue is suspended. */ protected void pop() throws EmptyStackException { if (prev == null) throw new EmptyStackException(); - + // Don't synchronize both this and prev at the same time, or deadlock could // occur. synchronized (prev) { prev.next = null; } - + synchronized (this) { int i = next_out; @@ -228,7 +285,7 @@ public class EventQueue } } } - + protected void dispatchEvent(AWTEvent evt) { if (evt instanceof ActiveEvent) |