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| 1 | /* | ||
| 2 | * Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved. | ||
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | ||
| 4 | * | ||
| 5 | * This code is free software; you can redistribute it and/or modify it | ||
| 6 | * under the terms of the GNU General Public License version 2 only, as | ||
| 7 | * published by the Free Software Foundation. Oracle designates this | ||
| 8 | * particular file as subject to the "Classpath" exception as provided | ||
| 9 | * by Oracle in the LICENSE file that accompanied this code. | ||
| 10 | * | ||
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT | ||
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | ||
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | ||
| 14 | * version 2 for more details (a copy is included in the LICENSE file that | ||
| 15 | * accompanied this code). | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU General Public License version | ||
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, | ||
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | ||
| 20 | * | ||
| 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | ||
| 22 | * or visit www.oracle.com if you need additional information or have any | ||
| 23 | * questions. | ||
| 24 | */ | ||
| 25 | |||
| 26 | package java.awt; | ||
| 27 | |||
| 28 | import java.util.LinkedList; | ||
| 29 | import sun.awt.AppContext; | ||
| 30 | import sun.awt.SunToolkit; | ||
| 31 | |||
| 32 | /** | ||
| 33 | * A mechanism for ensuring that a series of AWTEvents are executed in a | ||
| 34 | * precise order, even across multiple AppContexts. The nested events will be | ||
| 35 | * dispatched in the order in which their wrapping SequencedEvents were | ||
| 36 | * constructed. The only exception to this rule is if the peer of the target of | ||
| 37 | * the nested event was destroyed (with a call to Component.removeNotify) | ||
| 38 | * before the wrapping SequencedEvent was able to be dispatched. In this case, | ||
| 39 | * the nested event is never dispatched. | ||
| 40 | * | ||
| 41 | * @author David Mendenhall | ||
| 42 | */ | ||
| 43 | class SequencedEvent extends AWTEvent implements ActiveEvent { | ||
| 44 | /* | ||
| 45 | * serialVersionUID | ||
| 46 | */ | ||
| 47 | private static final long serialVersionUID = 547742659238625067L; | ||
| 48 | |||
| 49 | private static final int ID = | ||
| 50 | java.awt.event.FocusEvent.FOCUS_LAST + 1; | ||
| 51 | private static final LinkedList list = new LinkedList(); | ||
| 52 | |||
| 53 | private final AWTEvent nested; | ||
| 54 | private AppContext appContext; | ||
| 55 | private boolean disposed; | ||
| 56 | |||
| 57 | /** | ||
| 58 | * Constructs a new SequencedEvent which will dispatch the specified | ||
| 59 | * nested event. | ||
| 60 | * | ||
| 61 | * @param nested the AWTEvent which this SequencedEvent's dispatch() | ||
| 62 | * method will dispatch | ||
| 63 | */ | ||
| 64 | public SequencedEvent(AWTEvent nested) { | ||
| 65 | super(nested.getSource(), ID); | ||
| 66 | this.nested = nested; | ||
| 67 | // All AWTEvents that are wrapped in SequencedEvents are (at | ||
| 68 | // least currently) implicitly generated by the system | ||
| 69 | SunToolkit.setSystemGenerated(nested); | ||
| 70 | synchronized (SequencedEvent.class) { | ||
| 71 | list.add(this); | ||
| 72 | } | ||
| 73 | } | ||
| 74 | |||
| 75 | /** | ||
| 76 | * Dispatches the nested event after all previous nested events have been | ||
| 77 | * dispatched or disposed. If this method is invoked before all previous nested events | ||
| 78 | * have been dispatched, then this method blocks until such a point is | ||
| 79 | * reached. | ||
| 80 | * While waiting disposes nested events to disposed AppContext | ||
| 81 | * | ||
| 82 | * NOTE: Locking protocol. Since dispose() can get EventQueue lock, | ||
| 83 | * dispatch() shall never call dispose() while holding the lock on the list, | ||
| 84 | * as EventQueue lock is held during dispatching. The locks should be acquired | ||
| 85 | * in the same order. | ||
| 86 | */ | ||
| 87 | public final void dispatch() { | ||
| 88 | try { | ||
| 89 | appContext = AppContext.getAppContext(); | ||
| 90 | |||
| 91 | if (getFirst() != this) { | ||
| 92 | if (EventQueue.isDispatchThread()) { | ||
| 93 | EventDispatchThread edt = (EventDispatchThread) | ||
| 94 | Thread.currentThread(); | ||
| 95 | edt.pumpEvents(SentEvent.ID, new Conditional() { | ||
| 96 | public boolean evaluate() { | ||
| 97 | return !SequencedEvent.this.isFirstOrDisposed(); | ||
| 98 | } | ||
| 99 | }); | ||
| 100 | } else { | ||
| 101 | while(!isFirstOrDisposed()) { | ||
| 102 | synchronized (SequencedEvent.class) { | ||
| 103 | try { | ||
| 104 | SequencedEvent.class.wait(1000); | ||
| 105 | } catch (InterruptedException e) { | ||
| 106 | break; | ||
| 107 | } | ||
| 108 | } | ||
| 109 | } | ||
| 110 | } | ||
| 111 | } | ||
| 112 | |||
| 113 | if (!disposed) { | ||
| 114 | KeyboardFocusManager.getCurrentKeyboardFocusManager(). | ||
| 115 | setCurrentSequencedEvent(this); | ||
| 116 | Toolkit.getEventQueue().dispatchEvent(nested); | ||
| 117 | } | ||
| 118 | } finally { | ||
| 119 | dispose(); | ||
| 120 | } | ||
| 121 | } | ||
| 122 | |||
| 123 | /** | ||
| 124 | * true only if event exists and nested source appContext is disposed. | ||
| 125 | */ | ||
| 126 | private final static boolean isOwnerAppContextDisposed(SequencedEvent se) { | ||
| 127 | if (se != null) { | ||
| 128 | Object target = se.nested.getSource(); | ||
| 129 | if (target instanceof Component) { | ||
| 130 | return ((Component)target).appContext.isDisposed(); | ||
| 131 | } | ||
| 132 | } | ||
| 133 | return false; | ||
| 134 | } | ||
| 135 | |||
| 136 | /** | ||
| 137 | * Sequenced events are dispatched in order, so we cannot dispatch | ||
| 138 | * until we are the first sequenced event in the queue (i.e. it's our | ||
| 139 | * turn). But while we wait for our turn to dispatch, the event | ||
| 140 | * could have been disposed for a number of reasons. | ||
| 141 | */ | ||
| 142 | public final boolean isFirstOrDisposed() { | ||
| 143 | if (disposed) { | ||
| 144 | return true; | ||
| 145 | } | ||
| 146 | // getFirstWithContext can dispose this | ||
| 147 | return this == getFirstWithContext() || disposed; | ||
| 148 | } | ||
| 149 | |||
| 150 | private final synchronized static SequencedEvent getFirst() { | ||
| 151 | return (SequencedEvent)list.getFirst(); | ||
| 152 | } | ||
| 153 | |||
| 154 | /* Disposes all events from disposed AppContext | ||
| 155 | * return first valid event | ||
| 156 | */ | ||
| 157 | private final static SequencedEvent getFirstWithContext() { | ||
| 158 | SequencedEvent first = getFirst(); | ||
| 159 | while(isOwnerAppContextDisposed(first)) { | ||
| 160 | first.dispose(); | ||
| 161 | first = getFirst(); | ||
| 162 | } | ||
| 163 | return first; | ||
| 164 | } | ||
| 165 | |||
| 166 | /** | ||
| 167 | * Disposes of this instance. This method is invoked once the nested event | ||
| 168 | * has been dispatched and handled, or when the peer of the target of the | ||
| 169 | * nested event has been disposed with a call to Component.removeNotify. | ||
| 170 | * | ||
| 171 | * NOTE: Locking protocol. Since SunToolkit.postEvent can get EventQueue lock, | ||
| 172 | * it shall never be called while holding the lock on the list, | ||
| 173 | * as EventQueue lock is held during dispatching and dispatch() will get | ||
| 174 | * lock on the list. The locks should be acquired in the same order. | ||
| 175 | */ | ||
| 176 | final void dispose() { | ||
| 177 | synchronized (SequencedEvent.class) { | ||
| 178 | if (disposed) { | ||
| 179 | return; | ||
| 180 | } | ||
| 181 | if (KeyboardFocusManager.getCurrentKeyboardFocusManager(). | ||
| 182 | getCurrentSequencedEvent() == this) { | ||
| 183 | KeyboardFocusManager.getCurrentKeyboardFocusManager(). | ||
| 184 | setCurrentSequencedEvent(null); | ||
| 185 | } | ||
| 186 | disposed = true; | ||
| 187 | } | ||
| 188 | // Wake myself up | ||
| 189 | if (appContext != null) { | ||
| 190 | SunToolkit.postEvent(appContext, new SentEvent()); | ||
| 191 | } | ||
| 192 | |||
| 193 | SequencedEvent next = null; | ||
| 194 | |||
| 195 | synchronized (SequencedEvent.class) { | ||
| 196 | SequencedEvent.class.notifyAll(); | ||
| 197 | |||
| 198 | if (list.getFirst() == this) { | ||
| 199 | list.removeFirst(); | ||
| 200 | |||
| 201 | if (!list.isEmpty()) { | ||
| 202 | next = (SequencedEvent)list.getFirst(); | ||
| 203 | } | ||
| 204 | } else { | ||
| 205 | list.remove(this); | ||
| 206 | } | ||
| 207 | } | ||
| 208 | // Wake up waiting threads | ||
| 209 | if (next != null && next.appContext != null) { | ||
| 210 | SunToolkit.postEvent(next.appContext, new SentEvent()); | ||
| 211 | } | ||
| 212 | } | ||
| 213 | } | ||