1 /*
2 * Copyright (c) 2010, 2018, 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 javafx.application;
27
28 import com.sun.javafx.tk.Toolkit;
29 import javafx.beans.property.ReadOnlyBooleanProperty;
30 import javafx.beans.property.ReadOnlyBooleanWrapper;
31 import com.sun.javafx.application.PlatformImpl;
32
33 /**
34 * Application platform support class.
35 * @since JavaFX 2.0
36 */
37 public final class Platform {
38
39 // To prevent instantiation
40 private Platform() {
41 }
42
43 /**
44 * This method starts the JavaFX runtime. The specified Runnable will then be
45 * called on the JavaFX Application Thread. In general it is not necessary to
46 * explicitly call this method, since it is invoked as a consequence of
47 * how most JavaFX applications are built. However there are valid use cases
48 * for calling this method directly. Because this method starts the JavaFX
49 * runtime, there is not yet any JavaFX Application Thread, so it is normal
50 * that this method is called directly on the main thread of the application.
51 *
52 * <p>
53 * This method may or may not return to the caller before the run method
54 * of the specified Runnable has been called. In any case, once this method
55 * returns, you may call {@link #runLater(Runnable)} with additional Runnables.
56 * Those Runnables will be called, also on the JavaFX Application Thread,
57 * after the Runnable passed into this method has been called.
58 * </p>
59 *
60 * <p>As noted, it is normally the case that the JavaFX Application Thread
61 * is started automatically. It is important that this method only be called
62 * when the JavaFX runtime has not yet been initialized. Situations where
63 * the JavaFX runtime is started automatically include:
64 * </p>
65 *
66 * <ul>
67 * <li>For standard JavaFX applications that extend {@link Application}, and
68 * use either the Java launcher or one of the launch methods in the
69 * Application class to launch the application, the FX runtime is
70 * initialized automatically by the launcher before the {@code Application}
71 * class is loaded.</li>
72 * <li>For Swing applications that use {@link javafx.embed.swing.JFXPanel}
73 * to display FX content, the
74 * FX runtime is initialized when the first {@code JFXPanel} instance is
75 * constructed.</li>
76 * <li>For SWT application that use {@code FXCanvas} to display FX content,
77 * the FX runtime is initialized when the first {@code FXCanvas} instance is
78 * constructed.</li>
79 * </ul>
80 *
81 * <p>When an application does not follow any of these common approaches,
82 * then it becomes the responsibility of the developer to manually start the
83 * JavaFX runtime by calling this startup method.
84 * </p>
85 *
86 * <p>Calling this method when the JavaFX runtime is already running will result in an
87 * {@link IllegalStateException} being thrown - it is only valid to request
88 * that the JavaFX runtime be started once.
89 * </p>
90 *
91 * @throws IllegalStateException if the JavaFX runtime is already running
92 *
93 * @param runnable the Runnable whose run method will be executed on the
94 * JavaFX Application Thread once it has been started
95 *
96 * @see Application
97 *
98 * @since 9
99 */
100 public static void startup(Runnable runnable) {
101 PlatformImpl.startup(runnable, true);
102 }
103
104 /**
105 * Run the specified Runnable on the JavaFX Application Thread at some
106 * unspecified
107 * time in the future. This method, which may be called from any thread,
108 * will post the Runnable to an event queue and then return immediately to
109 * the caller. The Runnables are executed in the order they are posted.
110 * A runnable passed into the runLater method will be
111 * executed before any Runnable passed into a subsequent call to runLater.
112 * If this method is called after the JavaFX runtime has been shutdown, the
113 * call will be ignored: the Runnable will not be executed and no
114 * exception will be thrown.
115 *
116 * <p>
117 * NOTE: applications should avoid flooding JavaFX with too many
118 * pending Runnables. Otherwise, the application may become unresponsive.
119 * Applications are encouraged to batch up multiple operations into fewer
120 * runLater calls.
121 * Additionally, long-running operations should be done on a background
122 * thread where possible, freeing up the JavaFX Application Thread for GUI
123 * operations.
124 * </p>
125 *
126 * <p>
127 * This method must not be called before the FX runtime has been
128 * initialized. For standard JavaFX applications that extend
129 * {@link Application}, and use either the Java launcher or one of the
130 * launch methods in the Application class to launch the application,
131 * the FX runtime is initialized by the launcher before the Application
132 * class is loaded.
133 * For Swing applications that use JFXPanel to display FX content, the FX
134 * runtime is initialized when the first JFXPanel instance is constructed.
135 * For SWT application that use FXCanvas to display FX content, the FX
136 * runtime is initialized when the first FXCanvas instance is constructed.
137 * For applications that do not follow any of these approaches, then it is
138 * necessary to manually start the JavaFX runtime by calling
139 * {@link #startup(Runnable)} once.
140 * </p>
141 *
142 * @param runnable the Runnable whose run method will be executed on the
143 * JavaFX Application Thread
144 *
145 * @throws IllegalStateException if the FX runtime has not been initialized
146 *
147 * @see Application
148 */
149 public static void runLater(Runnable runnable) {
150 PlatformImpl.runLater(runnable);
151 }
152
153 // NOTE: Add the following if we decide to expose it publicly
154 // public static void runAndWait(Runnable runnable) {
155 // PlatformImpl.runAndWait(runnable);
156 // }
157
158 /**
159 * Requests the Java Runtime to perform a pulse. This will run a pulse
160 * even if there are no animation timers, scene graph modifications,
161 * or window events that would otherwise cause the pulse to run.
162 * If no pulse is in progress, then one will be scheduled to
163 * run the next time the pulse timer fires.
164 * If there is already a pulse running, then
165 * at least one more pulse after the current pulse will be scheduled.
166 * This method may be called on any thread.
167 *
168 * @since 9
169 */
170 public static void requestNextPulse() {
171 Toolkit.getToolkit().requestNextPulse();
172 }
173
174 /**
175 * Returns true if the calling thread is the JavaFX Application Thread.
176 * Use this call the ensure that a given task is being executed
177 * (or not being executed) on the JavaFX Application Thread.
178 *
179 * @return true if running on the JavaFX Application Thread
180 */
181 public static boolean isFxApplicationThread() {
182 return PlatformImpl.isFxApplicationThread();
183 }
184
185 /**
186 * Causes the JavaFX application to terminate. If this method is called
187 * after the Application start method is called, then the JavaFX launcher
188 * will call the Application stop method and terminate the JavaFX
189 * application thread. The launcher thread will then shutdown. If there
190 * are no other non-daemon threads that are running, the Java VM will exit.
191 * If this method is called from the Preloader or the Application init
192 * method, then the Application stop method may not be called.
193 *
194 * <p>This method may be called from any thread.</p>
195 */
196 public static void exit() {
197 PlatformImpl.exit();
198 }
199
200 /**
201 * Sets the implicitExit attribute to the specified value. If this
202 * attribute is true, the JavaFX runtime will implicitly shutdown
203 * when the last window is closed; the JavaFX launcher will call the
204 * {@link Application#stop} method and terminate the JavaFX
205 * application thread.
206 * If this attribute is false, the application will continue to
207 * run normally even after the last window is closed, until the
208 * application calls {@link #exit}.
209 * The default value is true.
210 *
211 * <p>This method may be called from any thread.</p>
212 *
213 * @param implicitExit a flag indicating whether or not to implicitly exit
214 * when the last window is closed.
215 * @since JavaFX 2.2
216 */
217 public static void setImplicitExit(boolean implicitExit) {
218 PlatformImpl.setImplicitExit(implicitExit);
219 }
220
221 /**
222 * Gets the value of the implicitExit attribute.
223 *
224 * <p>This method may be called from any thread.</p>
225 *
226 * @return the implicitExit attribute
227 * @since JavaFX 2.2
228 */
229 public static boolean isImplicitExit() {
230 return PlatformImpl.isImplicitExit();
231 }
232
233 /**
234 * Queries whether a specific conditional feature is supported
235 * by the platform.
236 * <p>
237 * For example:
238 * <pre>
239 * // Query whether filter effects are supported
240 * if (Platform.isSupported(ConditionalFeature.EFFECT)) {
241 * // use effects
242 * }
243 * </pre>
244 *
245 * @param feature the conditional feature in question.
246 * @return true if a specific conditional feature is supported by the
247 * platform, otherwise false
248 */
249 public static boolean isSupported(ConditionalFeature feature) {
250 return PlatformImpl.isSupported(feature);
251 }
252
253 /**
254 * Enter a nested event loop and block until the corresponding
255 * exitNestedEventLoop call is made.
256 * The key passed into this method is used to
257 * uniquely identify the matched enter/exit pair. This method creates a
258 * new nested event loop and blocks until the corresponding
259 * exitNestedEventLoop method is called with the same key.
260 * The return value of this method will be the {@code rval}
261 * object supplied to the exitNestedEventLoop method call that unblocks it.
262 *
263 * <p>
264 * This method must either be called from an input event handler or
265 * from the run method of a Runnable passed to
266 * {@link javafx.application.Platform#runLater Platform.runLater}.
267 * It must not be called during animation or layout processing.
268 * </p>
269 *
270 * @param key the Object that identifies the nested event loop, which
271 * must not be null
272 *
273 * @throws IllegalArgumentException if the specified key is associated
274 * with a nested event loop that has not yet returned
275 *
276 * @throws NullPointerException if the key is null
277 *
278 * @throws IllegalStateException if this method is called during
279 * animation or layout processing.
280 *
281 * @throws IllegalStateException if this method is called on a thread
282 * other than the JavaFX Application Thread.
283 *
284 * @return the value passed into the corresponding call to exitEventLoop
285 *
286 * @since 9
287 */
288 public static Object enterNestedEventLoop(Object key) {
289 return Toolkit.getToolkit().enterNestedEventLoop(key);
290 }
291
292 /**
293 * Exit a nested event loop and unblock the caller of the
294 * corresponding enterNestedEventLoop.
295 * The key passed into this method is used to
296 * uniquely identify the matched enter/exit pair. This method causes the
297 * nested event loop that was previously created with the key to exit and
298 * return control to the caller. If the specified nested event loop is not
299 * the inner-most loop then it will not return until all other inner loops
300 * also exit.
301 *
302 * @param key the Object that identifies the nested event loop, which
303 * must not be null
304 *
305 * @param rval an Object that is returned to the caller of the
306 * corresponding enterNestedEventLoop. This may be null.
307 *
308 * @throws IllegalArgumentException if the specified key is not associated
309 * with an active nested event loop
310 *
311 * @throws NullPointerException if the key is null
312 *
313 * @throws IllegalStateException if this method is called on a thread
314 * other than the FX Application thread
315 *
316 * @since 9
317 */
318 public static void exitNestedEventLoop(Object key, Object rval) {
319 Toolkit.getToolkit().exitNestedEventLoop(key, rval);
320 }
321
322 /**
323 * Checks whether a nested event loop is running, returning true to indicate
324 * that one is, and false if there are no nested event loops currently
325 * running.
326 * This method must be called on the JavaFX Application thread.
327 *
328 * @return true if there is a nested event loop running, and false otherwise.
329 *
330 * @throws IllegalStateException if this method is called on a thread
331 * other than the JavaFX Application Thread.
332 *
333 * @since 9
334 */
335 public static boolean isNestedLoopRunning() {
336 return Toolkit.getToolkit().isNestedLoopRunning();
337 }
338
339 private static ReadOnlyBooleanWrapper accessibilityActiveProperty;
340
341 public static boolean isAccessibilityActive() {
342 return accessibilityActiveProperty == null ? false : accessibilityActiveProperty.get();
343 }
344
345 /**
346 * Indicates whether or not accessibility is active.
347 * This property is typically set to true the first time an
348 * assistive technology, such as a screen reader, requests
349 * information about any JavaFX window or its children.
350 *
351 * <p>This method may be called from any thread.</p>
352 *
353 * @return the read-only boolean property indicating if accessibility is active
354 *
355 * @since JavaFX 8u40
356 */
357 public static ReadOnlyBooleanProperty accessibilityActiveProperty() {
358 if (accessibilityActiveProperty == null) {
359 accessibilityActiveProperty = new ReadOnlyBooleanWrapper(Platform.class, "accessibilityActive");
360 accessibilityActiveProperty.bind(PlatformImpl.accessibilityActiveProperty());
361 }
362 return accessibilityActiveProperty.getReadOnlyProperty();
363 }
364 }