| /* |
| * Copyright (c) 2000, 2006, Oracle and/or its affiliates. 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. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package sun.awt; |
| |
| import java.awt.AWTEvent; |
| import java.util.Collections; |
| import java.util.HashSet; |
| import java.util.IdentityHashMap; |
| import java.util.Map; |
| import sun.util.logging.PlatformLogger; |
| |
| /** |
| * This class is to let AWT shutdown automatically when a user is done |
| * with AWT. It tracks AWT state using the following parameters: |
| * <ul> |
| * <li><code>peerMap</code> - the map between the existing peer objects |
| * and their associated targets |
| * <li><code>toolkitThreadBusy</code> - whether the toolkit thread |
| * is waiting for a new native event to appear in its queue |
| * or is dispatching an event |
| * <li><code>busyThreadSet</code> - a set of all the event dispatch |
| * threads that are busy at this moment, i.e. those that are not |
| * waiting for a new event to appear in their event queue. |
| * </ul><p> |
| * AWT is considered to be in ready-to-shutdown state when |
| * <code>peerMap</code> is empty and <code>toolkitThreadBusy</code> |
| * is false and <code>busyThreadSet</code> is empty. |
| * The internal AWTAutoShutdown logic secures that the single non-daemon |
| * thread (<code>blockerThread</code>) is running when AWT is not in |
| * ready-to-shutdown state. This blocker thread is to prevent AWT from |
| * exiting since the toolkit thread is now daemon and all the event |
| * dispatch threads are started only when needed. Once it is detected |
| * that AWT is in ready-to-shutdown state this blocker thread waits |
| * for a certain timeout and if AWT state doesn't change during timeout |
| * this blocker thread terminates all the event dispatch threads and |
| * exits. |
| */ |
| public final class AWTAutoShutdown implements Runnable { |
| |
| private static final AWTAutoShutdown theInstance = new AWTAutoShutdown(); |
| |
| /** |
| * This lock object is used to synchronize shutdown operations. |
| */ |
| private final Object mainLock = new Object(); |
| |
| /** |
| * This lock object is to secure that when a new blocker thread is |
| * started it will be the first who acquire the main lock after |
| * the thread that created the new blocker released the main lock |
| * by calling lock.wait() to wait for the blocker to start. |
| */ |
| private final Object activationLock = new Object(); |
| |
| /** |
| * This set keeps references to all the event dispatch threads that |
| * are busy at this moment, i.e. those that are not waiting for a |
| * new event to appear in their event queue. |
| * Access is synchronized on the main lock object. |
| */ |
| private final HashSet busyThreadSet = new HashSet(7); |
| |
| /** |
| * Indicates whether the toolkit thread is waiting for a new native |
| * event to appear or is dispatching an event. |
| */ |
| private boolean toolkitThreadBusy = false; |
| |
| /** |
| * This is a map between components and their peers. |
| * we should work with in under activationLock&mainLock lock. |
| */ |
| private final Map peerMap = new IdentityHashMap(); |
| |
| /** |
| * References the alive non-daemon thread that is currently used |
| * for keeping AWT from exiting. |
| */ |
| private Thread blockerThread = null; |
| |
| /** |
| * We need this flag to secure that AWT state hasn't changed while |
| * we were waiting for the safety timeout to pass. |
| */ |
| private boolean timeoutPassed = false; |
| |
| /** |
| * Once we detect that AWT is ready to shutdown we wait for a certain |
| * timeout to pass before stopping event dispatch threads. |
| */ |
| private static final int SAFETY_TIMEOUT = 1000; |
| |
| /** |
| * Constructor method is intentionally made private to secure |
| * a single instance. Use getInstance() to reference it. |
| * |
| * @see AWTAutoShutdown#getInstance |
| */ |
| private AWTAutoShutdown() {} |
| |
| /** |
| * Returns reference to a single AWTAutoShutdown instance. |
| */ |
| public static AWTAutoShutdown getInstance() { |
| return theInstance; |
| } |
| |
| /** |
| * Notify that the toolkit thread is not waiting for a native event |
| * to appear in its queue. |
| * |
| * @see AWTAutoShutdown#notifyToolkitThreadFree |
| * @see AWTAutoShutdown#setToolkitBusy |
| * @see AWTAutoShutdown#isReadyToShutdown |
| */ |
| public static void notifyToolkitThreadBusy() { |
| getInstance().setToolkitBusy(true); |
| } |
| |
| /** |
| * Notify that the toolkit thread is waiting for a native event |
| * to appear in its queue. |
| * |
| * @see AWTAutoShutdown#notifyToolkitThreadFree |
| * @see AWTAutoShutdown#setToolkitBusy |
| * @see AWTAutoShutdown#isReadyToShutdown |
| */ |
| public static void notifyToolkitThreadFree() { |
| getInstance().setToolkitBusy(false); |
| } |
| |
| /** |
| * Add a specified thread to the set of busy event dispatch threads. |
| * If this set already contains the specified thread or the thread is null, |
| * the call leaves this set unchanged and returns silently. |
| * |
| * @param thread thread to be added to this set, if not present. |
| * @see AWTAutoShutdown#notifyThreadFree |
| * @see AWTAutoShutdown#isReadyToShutdown |
| */ |
| public void notifyThreadBusy(final Thread thread) { |
| if (thread == null) { |
| return; |
| } |
| synchronized (activationLock) { |
| synchronized (mainLock) { |
| if (blockerThread == null) { |
| activateBlockerThread(); |
| } else if (isReadyToShutdown()) { |
| mainLock.notifyAll(); |
| timeoutPassed = false; |
| } |
| busyThreadSet.add(thread); |
| } |
| } |
| } |
| |
| /** |
| * Remove a specified thread from the set of busy event dispatch threads. |
| * If this set doesn't contain the specified thread or the thread is null, |
| * the call leaves this set unchanged and returns silently. |
| * |
| * @param thread thread to be removed from this set, if present. |
| * @see AWTAutoShutdown#notifyThreadBusy |
| * @see AWTAutoShutdown#isReadyToShutdown |
| */ |
| public void notifyThreadFree(final Thread thread) { |
| if (thread == null) { |
| return; |
| } |
| synchronized (activationLock) { |
| synchronized (mainLock) { |
| busyThreadSet.remove(thread); |
| if (isReadyToShutdown()) { |
| mainLock.notifyAll(); |
| timeoutPassed = false; |
| } |
| } |
| } |
| } |
| |
| /** |
| * Notify that the peermap has been updated, that means a new peer |
| * has been created or some existing peer has been disposed. |
| * |
| * @see AWTAutoShutdown#isReadyToShutdown |
| */ |
| void notifyPeerMapUpdated() { |
| synchronized (activationLock) { |
| synchronized (mainLock) { |
| if (!isReadyToShutdown() && blockerThread == null) { |
| activateBlockerThread(); |
| } else { |
| mainLock.notifyAll(); |
| timeoutPassed = false; |
| } |
| } |
| } |
| } |
| |
| /** |
| * Determine whether AWT is currently in ready-to-shutdown state. |
| * AWT is considered to be in ready-to-shutdown state if |
| * <code>peerMap</code> is empty and <code>toolkitThreadBusy</code> |
| * is false and <code>busyThreadSet</code> is empty. |
| * |
| * @return true if AWT is in ready-to-shutdown state. |
| */ |
| private boolean isReadyToShutdown() { |
| return (!toolkitThreadBusy && |
| peerMap.isEmpty() && |
| busyThreadSet.isEmpty()); |
| } |
| |
| /** |
| * Notify about the toolkit thread state change. |
| * |
| * @param busy true if the toolkit thread state changes from idle |
| * to busy. |
| * @see AWTAutoShutdown#notifyToolkitThreadBusy |
| * @see AWTAutoShutdown#notifyToolkitThreadFree |
| * @see AWTAutoShutdown#isReadyToShutdown |
| */ |
| private void setToolkitBusy(final boolean busy) { |
| if (busy != toolkitThreadBusy) { |
| synchronized (activationLock) { |
| synchronized (mainLock) { |
| if (busy != toolkitThreadBusy) { |
| if (busy) { |
| if (blockerThread == null) { |
| activateBlockerThread(); |
| } else if (isReadyToShutdown()) { |
| mainLock.notifyAll(); |
| timeoutPassed = false; |
| } |
| toolkitThreadBusy = busy; |
| } else { |
| toolkitThreadBusy = busy; |
| if (isReadyToShutdown()) { |
| mainLock.notifyAll(); |
| timeoutPassed = false; |
| } |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| /** |
| * Implementation of the Runnable interface. |
| * Incapsulates the blocker thread functionality. |
| * |
| * @see AWTAutoShutdown#isReadyToShutdown |
| */ |
| public void run() { |
| Thread currentThread = Thread.currentThread(); |
| boolean interrupted = false; |
| synchronized (mainLock) { |
| try { |
| /* Notify that the thread is started. */ |
| mainLock.notifyAll(); |
| while (blockerThread == currentThread) { |
| mainLock.wait(); |
| timeoutPassed = false; |
| /* |
| * This loop is introduced to handle the following case: |
| * it is possible that while we are waiting for the |
| * safety timeout to pass AWT state can change to |
| * not-ready-to-shutdown and back to ready-to-shutdown. |
| * In this case we have to wait once again. |
| * NOTE: we shouldn't break into the outer loop |
| * in this case, since we may never be notified |
| * in an outer infinite wait at this point. |
| */ |
| while (isReadyToShutdown()) { |
| if (timeoutPassed) { |
| timeoutPassed = false; |
| blockerThread = null; |
| break; |
| } |
| timeoutPassed = true; |
| mainLock.wait(SAFETY_TIMEOUT); |
| } |
| } |
| } catch (InterruptedException e) { |
| interrupted = true; |
| } finally { |
| if (blockerThread == currentThread) { |
| blockerThread = null; |
| } |
| } |
| } |
| if (!interrupted) { |
| AppContext.stopEventDispatchThreads(); |
| } |
| } |
| |
| static AWTEvent getShutdownEvent() { |
| return new AWTEvent(getInstance(), 0) {}; |
| } |
| |
| /** |
| * Creates and starts a new blocker thread. Doesn't return until |
| * the new blocker thread starts. |
| */ |
| private void activateBlockerThread() { |
| Thread thread = new Thread(this, "AWT-Shutdown"); |
| thread.setDaemon(false); |
| blockerThread = thread; |
| thread.start(); |
| try { |
| /* Wait for the blocker thread to start. */ |
| mainLock.wait(); |
| } catch (InterruptedException e) { |
| System.err.println("AWT blocker activation interrupted:"); |
| e.printStackTrace(); |
| } |
| } |
| |
| final void registerPeer(final Object target, final Object peer) { |
| synchronized (activationLock) { |
| synchronized (mainLock) { |
| peerMap.put(target, peer); |
| notifyPeerMapUpdated(); |
| } |
| } |
| } |
| |
| final void unregisterPeer(final Object target, final Object peer) { |
| synchronized (activationLock) { |
| synchronized (mainLock) { |
| if (peerMap.get(target) == peer) { |
| peerMap.remove(target); |
| notifyPeerMapUpdated(); |
| } |
| } |
| } |
| } |
| |
| final Object getPeer(final Object target) { |
| synchronized (activationLock) { |
| synchronized (mainLock) { |
| return peerMap.get(target); |
| } |
| } |
| } |
| |
| final void dumpPeers(final PlatformLogger aLog) { |
| synchronized (activationLock) { |
| synchronized (mainLock) { |
| aLog.fine("Mapped peers:"); |
| for (Object key : peerMap.keySet()) { |
| aLog.fine(key + "->" + peerMap.get(key)); |
| } |
| } |
| } |
| } |
| |
| } // class AWTAutoShutdown |
