| /* |
| * Copyright (c) 1997, 2008, 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 javax.swing; |
| |
| |
| |
| import java.util.*; |
| import java.util.concurrent.atomic.AtomicBoolean; |
| import java.util.concurrent.locks.*; |
| import java.awt.*; |
| import java.awt.event.*; |
| import java.io.Serializable; |
| import javax.swing.event.EventListenerList; |
| |
| |
| |
| /** |
| * Fires one or more {@code ActionEvent}s at specified |
| * intervals. An example use is an animation object that uses a |
| * <code>Timer</code> as the trigger for drawing its frames. |
| *<p> |
| * Setting up a timer |
| * involves creating a <code>Timer</code> object, |
| * registering one or more action listeners on it, |
| * and starting the timer using |
| * the <code>start</code> method. |
| * For example, |
| * the following code creates and starts a timer |
| * that fires an action event once per second |
| * (as specified by the first argument to the <code>Timer</code> constructor). |
| * The second argument to the <code>Timer</code> constructor |
| * specifies a listener to receive the timer's action events. |
| * |
| *<pre> |
| * int delay = 1000; //milliseconds |
| * ActionListener taskPerformer = new ActionListener() { |
| * public void actionPerformed(ActionEvent evt) { |
| * <em>//...Perform a task...</em> |
| * } |
| * }; |
| * new Timer(delay, taskPerformer).start();</pre> |
| * |
| * <p> |
| * {@code Timers} are constructed by specifying both a delay parameter |
| * and an {@code ActionListener}. The delay parameter is used |
| * to set both the initial delay and the delay between event |
| * firing, in milliseconds. Once the timer has been started, |
| * it waits for the initial delay before firing its |
| * first <code>ActionEvent</code> to registered listeners. |
| * After this first event, it continues to fire events |
| * every time the between-event delay has elapsed, until it |
| * is stopped. |
| * <p> |
| * After construction, the initial delay and the between-event |
| * delay can be changed independently, and additional |
| * <code>ActionListeners</code> may be added. |
| * <p> |
| * If you want the timer to fire only the first time and then stop, |
| * invoke <code>setRepeats(false)</code> on the timer. |
| * <p> |
| * Although all <code>Timer</code>s perform their waiting |
| * using a single, shared thread |
| * (created by the first <code>Timer</code> object that executes), |
| * the action event handlers for <code>Timer</code>s |
| * execute on another thread -- the event-dispatching thread. |
| * This means that the action handlers for <code>Timer</code>s |
| * can safely perform operations on Swing components. |
| * However, it also means that the handlers must execute quickly |
| * to keep the GUI responsive. |
| * |
| * <p> |
| * In v 1.3, another <code>Timer</code> class was added |
| * to the Java platform: <code>java.util.Timer</code>. |
| * Both it and <code>javax.swing.Timer</code> |
| * provide the same basic functionality, |
| * but <code>java.util.Timer</code> |
| * is more general and has more features. |
| * The <code>javax.swing.Timer</code> has two features |
| * that can make it a little easier to use with GUIs. |
| * First, its event handling metaphor is familiar to GUI programmers |
| * and can make dealing with the event-dispatching thread |
| * a bit simpler. |
| * Second, its |
| * automatic thread sharing means that you don't have to |
| * take special steps to avoid spawning |
| * too many threads. |
| * Instead, your timer uses the same thread |
| * used to make cursors blink, |
| * tool tips appear, |
| * and so on. |
| * |
| * <p> |
| * You can find further documentation |
| * and several examples of using timers by visiting |
| * <a href="http://java.sun.com/docs/books/tutorial/uiswing/misc/timer.html" |
| * target = "_top">How to Use Timers</a>, |
| * a section in <em>The Java Tutorial.</em> |
| * For more examples and help in choosing between |
| * this <code>Timer</code> class and |
| * <code>java.util.Timer</code>, |
| * see |
| * <a href="http://java.sun.com/products/jfc/tsc/articles/timer/" |
| * target="_top">Using Timers in Swing Applications</a>, |
| * an article in <em>The Swing Connection.</em> |
| * <p> |
| * <strong>Warning:</strong> |
| * Serialized objects of this class will not be compatible with |
| * future Swing releases. The current serialization support is |
| * appropriate for short term storage or RMI between applications running |
| * the same version of Swing. As of 1.4, support for long term storage |
| * of all JavaBeans<sup><font size="-2">TM</font></sup> |
| * has been added to the <code>java.beans</code> package. |
| * Please see {@link java.beans.XMLEncoder}. |
| * |
| * @see java.util.Timer <code>java.util.Timer</code> |
| * |
| * |
| * @author Dave Moore |
| */ |
| public class Timer implements Serializable |
| { |
| /* |
| * NOTE: all fields need to be handled in readResolve |
| */ |
| |
| protected EventListenerList listenerList = new EventListenerList(); |
| |
| // The following field strives to maintain the following: |
| // If coalesce is true, only allow one Runnable to be queued on the |
| // EventQueue and be pending (ie in the process of notifying the |
| // ActionListener). If we didn't do this it would allow for a |
| // situation where the app is taking too long to process the |
| // actionPerformed, and thus we'ld end up queing a bunch of Runnables |
| // and the app would never return: not good. This of course implies |
| // you can get dropped events, but such is life. |
| // notify is used to indicate if the ActionListener can be notified, when |
| // the Runnable is processed if this is true it will notify the listeners. |
| // notify is set to true when the Timer fires and the Runnable is queued. |
| // It will be set to false after notifying the listeners (if coalesce is |
| // true) or if the developer invokes stop. |
| private transient final AtomicBoolean notify = new AtomicBoolean(false); |
| |
| private volatile int initialDelay, delay; |
| private volatile boolean repeats = true, coalesce = true; |
| |
| private transient final Runnable doPostEvent; |
| |
| private static volatile boolean logTimers; |
| |
| private transient final Lock lock = new ReentrantLock(); |
| |
| // This field is maintained by TimerQueue. |
| // eventQueued can also be reset by the TimerQueue, but will only ever |
| // happen in applet case when TimerQueues thread is destroyed. |
| // access to this field is synchronized on getLock() lock. |
| transient TimerQueue.DelayedTimer delayedTimer = null; |
| |
| private volatile String actionCommand; |
| |
| /** |
| * Creates a {@code Timer} and initializes both the initial delay and |
| * between-event delay to {@code delay} milliseconds. If {@code delay} |
| * is less than or equal to zero, the timer fires as soon as it |
| * is started. If <code>listener</code> is not <code>null</code>, |
| * it's registered as an action listener on the timer. |
| * |
| * @param delay milliseconds for the initial and between-event delay |
| * @param listener an initial listener; can be <code>null</code> |
| * |
| * @see #addActionListener |
| * @see #setInitialDelay |
| * @see #setRepeats |
| */ |
| public Timer(int delay, ActionListener listener) { |
| super(); |
| this.delay = delay; |
| this.initialDelay = delay; |
| |
| doPostEvent = new DoPostEvent(); |
| |
| if (listener != null) { |
| addActionListener(listener); |
| } |
| } |
| |
| |
| /** |
| * DoPostEvent is a runnable class that fires actionEvents to |
| * the listeners on the EventDispatchThread, via invokeLater. |
| * @see Timer#post |
| */ |
| class DoPostEvent implements Runnable |
| { |
| public void run() { |
| if (logTimers) { |
| System.out.println("Timer ringing: " + Timer.this); |
| } |
| if(notify.get()) { |
| fireActionPerformed(new ActionEvent(Timer.this, 0, getActionCommand(), |
| System.currentTimeMillis(), |
| 0)); |
| if (coalesce) { |
| cancelEvent(); |
| } |
| } |
| } |
| |
| Timer getTimer() { |
| return Timer.this; |
| } |
| } |
| |
| /** |
| * Adds an action listener to the <code>Timer</code>. |
| * |
| * @param listener the listener to add |
| * |
| * @see #Timer |
| */ |
| public void addActionListener(ActionListener listener) { |
| listenerList.add(ActionListener.class, listener); |
| } |
| |
| |
| /** |
| * Removes the specified action listener from the <code>Timer</code>. |
| * |
| * @param listener the listener to remove |
| */ |
| public void removeActionListener(ActionListener listener) { |
| listenerList.remove(ActionListener.class, listener); |
| } |
| |
| |
| /** |
| * Returns an array of all the action listeners registered |
| * on this timer. |
| * |
| * @return all of the timer's <code>ActionListener</code>s or an empty |
| * array if no action listeners are currently registered |
| * |
| * @see #addActionListener |
| * @see #removeActionListener |
| * |
| * @since 1.4 |
| */ |
| public ActionListener[] getActionListeners() { |
| return listenerList.getListeners(ActionListener.class); |
| } |
| |
| |
| /** |
| * Notifies all listeners that have registered interest for |
| * notification on this event type. |
| * |
| * @param e the action event to fire |
| * @see EventListenerList |
| */ |
| protected void fireActionPerformed(ActionEvent e) { |
| // Guaranteed to return a non-null array |
| Object[] listeners = listenerList.getListenerList(); |
| |
| // Process the listeners last to first, notifying |
| // those that are interested in this event |
| for (int i=listeners.length-2; i>=0; i-=2) { |
| if (listeners[i]==ActionListener.class) { |
| ((ActionListener)listeners[i+1]).actionPerformed(e); |
| } |
| } |
| } |
| |
| /** |
| * Returns an array of all the objects currently registered as |
| * <code><em>Foo</em>Listener</code>s |
| * upon this <code>Timer</code>. |
| * <code><em>Foo</em>Listener</code>s |
| * are registered using the <code>add<em>Foo</em>Listener</code> method. |
| * <p> |
| * You can specify the <code>listenerType</code> argument |
| * with a class literal, such as <code><em>Foo</em>Listener.class</code>. |
| * For example, you can query a <code>Timer</code> |
| * instance <code>t</code> |
| * for its action listeners |
| * with the following code: |
| * |
| * <pre>ActionListener[] als = (ActionListener[])(t.getListeners(ActionListener.class));</pre> |
| * |
| * If no such listeners exist, |
| * this method returns an empty array. |
| * |
| * @param listenerType the type of listeners requested; |
| * this parameter should specify an interface |
| * that descends from <code>java.util.EventListener</code> |
| * @return an array of all objects registered as |
| * <code><em>Foo</em>Listener</code>s |
| * on this timer, |
| * or an empty array if no such |
| * listeners have been added |
| * @exception ClassCastException if <code>listenerType</code> doesn't |
| * specify a class or interface that implements |
| * <code>java.util.EventListener</code> |
| * |
| * @see #getActionListeners |
| * @see #addActionListener |
| * @see #removeActionListener |
| * |
| * @since 1.3 |
| */ |
| public <T extends EventListener> T[] getListeners(Class<T> listenerType) { |
| return listenerList.getListeners(listenerType); |
| } |
| |
| /** |
| * Returns the timer queue. |
| */ |
| private TimerQueue timerQueue() { |
| return TimerQueue.sharedInstance(); |
| } |
| |
| |
| /** |
| * Enables or disables the timer log. When enabled, a message |
| * is posted to <code>System.out</code> whenever the timer goes off. |
| * |
| * @param flag <code>true</code> to enable logging |
| * @see #getLogTimers |
| */ |
| public static void setLogTimers(boolean flag) { |
| logTimers = flag; |
| } |
| |
| |
| /** |
| * Returns <code>true</code> if logging is enabled. |
| * |
| * @return <code>true</code> if logging is enabled; otherwise, false |
| * @see #setLogTimers |
| */ |
| public static boolean getLogTimers() { |
| return logTimers; |
| } |
| |
| |
| /** |
| * Sets the <code>Timer</code>'s between-event delay, the number of milliseconds |
| * between successive action events. This does not affect the initial delay |
| * property, which can be set by the {@code setInitialDelay} method. |
| * |
| * @param delay the delay in milliseconds |
| * @see #setInitialDelay |
| */ |
| public void setDelay(int delay) { |
| if (delay < 0) { |
| throw new IllegalArgumentException("Invalid delay: " + delay); |
| } |
| else { |
| this.delay = delay; |
| } |
| } |
| |
| |
| /** |
| * Returns the delay, in milliseconds, |
| * between firings of action events. |
| * |
| * @see #setDelay |
| * @see #getInitialDelay |
| */ |
| public int getDelay() { |
| return delay; |
| } |
| |
| |
| /** |
| * Sets the <code>Timer</code>'s initial delay, the time |
| * in milliseconds to wait after the timer is started |
| * before firing the first event. Upon construction, this |
| * is set to be the same as the between-event delay, |
| * but then its value is independent and remains unaffected |
| * by changes to the between-event delay. |
| * |
| * @param initialDelay the initial delay, in milliseconds |
| * @see #setDelay |
| */ |
| public void setInitialDelay(int initialDelay) { |
| if (initialDelay < 0) { |
| throw new IllegalArgumentException("Invalid initial delay: " + |
| initialDelay); |
| } |
| else { |
| this.initialDelay = initialDelay; |
| } |
| } |
| |
| |
| /** |
| * Returns the <code>Timer</code>'s initial delay. |
| * |
| * @see #setInitialDelay |
| * @see #setDelay |
| */ |
| public int getInitialDelay() { |
| return initialDelay; |
| } |
| |
| |
| /** |
| * If <code>flag</code> is <code>false</code>, |
| * instructs the <code>Timer</code> to send only one |
| * action event to its listeners. |
| * |
| * @param flag specify <code>false</code> to make the timer |
| * stop after sending its first action event |
| */ |
| public void setRepeats(boolean flag) { |
| repeats = flag; |
| } |
| |
| |
| /** |
| * Returns <code>true</code> (the default) |
| * if the <code>Timer</code> will send |
| * an action event |
| * to its listeners multiple times. |
| * |
| * @see #setRepeats |
| */ |
| public boolean isRepeats() { |
| return repeats; |
| } |
| |
| |
| /** |
| * Sets whether the <code>Timer</code> coalesces multiple pending |
| * <code>ActionEvent</code> firings. |
| * A busy application may not be able |
| * to keep up with a <code>Timer</code>'s event generation, |
| * causing multiple |
| * action events to be queued. When processed, |
| * the application sends these events one after the other, causing the |
| * <code>Timer</code>'s listeners to receive a sequence of |
| * events with no delay between them. Coalescing avoids this situation |
| * by reducing multiple pending events to a single event. |
| * <code>Timer</code>s |
| * coalesce events by default. |
| * |
| * @param flag specify <code>false</code> to turn off coalescing |
| */ |
| public void setCoalesce(boolean flag) { |
| boolean old = coalesce; |
| coalesce = flag; |
| if (!old && coalesce) { |
| // We must do this as otherwise if the Timer once notified |
| // in !coalese mode notify will be stuck to true and never |
| // become false. |
| cancelEvent(); |
| } |
| } |
| |
| |
| /** |
| * Returns <code>true</code> if the <code>Timer</code> coalesces |
| * multiple pending action events. |
| * |
| * @see #setCoalesce |
| */ |
| public boolean isCoalesce() { |
| return coalesce; |
| } |
| |
| |
| /** |
| * Sets the string that will be delivered as the action command |
| * in <code>ActionEvent</code>s fired by this timer. |
| * <code>null</code> is an acceptable value. |
| * |
| * @param command the action command |
| * @since 1.6 |
| */ |
| public void setActionCommand(String command) { |
| this.actionCommand = command; |
| } |
| |
| |
| /** |
| * Returns the string that will be delivered as the action command |
| * in <code>ActionEvent</code>s fired by this timer. May be |
| * <code>null</code>, which is also the default. |
| * |
| * @return the action command used in firing events |
| * @since 1.6 |
| */ |
| public String getActionCommand() { |
| return actionCommand; |
| } |
| |
| |
| /** |
| * Starts the <code>Timer</code>, |
| * causing it to start sending action events |
| * to its listeners. |
| * |
| * @see #stop |
| */ |
| public void start() { |
| timerQueue().addTimer(this, getInitialDelay()); |
| } |
| |
| |
| /** |
| * Returns <code>true</code> if the <code>Timer</code> is running. |
| * |
| * @see #start |
| */ |
| public boolean isRunning() { |
| return timerQueue().containsTimer(this); |
| } |
| |
| |
| /** |
| * Stops the <code>Timer</code>, |
| * causing it to stop sending action events |
| * to its listeners. |
| * |
| * @see #start |
| */ |
| public void stop() { |
| getLock().lock(); |
| try { |
| cancelEvent(); |
| timerQueue().removeTimer(this); |
| } finally { |
| getLock().unlock(); |
| } |
| } |
| |
| |
| /** |
| * Restarts the <code>Timer</code>, |
| * canceling any pending firings and causing |
| * it to fire with its initial delay. |
| */ |
| public void restart() { |
| getLock().lock(); |
| try { |
| stop(); |
| start(); |
| } finally { |
| getLock().unlock(); |
| } |
| } |
| |
| |
| /** |
| * Resets the internal state to indicate this Timer shouldn't notify |
| * any of its listeners. This does not stop a repeatable Timer from |
| * firing again, use <code>stop</code> for that. |
| */ |
| void cancelEvent() { |
| notify.set(false); |
| } |
| |
| |
| void post() { |
| if (notify.compareAndSet(false, true) || !coalesce) { |
| SwingUtilities.invokeLater(doPostEvent); |
| } |
| } |
| |
| Lock getLock() { |
| return lock; |
| } |
| |
| /* |
| * We have to use readResolve because we can not initialize final |
| * fields for deserialized object otherwise |
| */ |
| private Object readResolve() { |
| Timer timer = new Timer(getDelay(), null); |
| timer.listenerList = listenerList; |
| timer.initialDelay = initialDelay; |
| timer.delay = delay; |
| timer.repeats = repeats; |
| timer.coalesce = coalesce; |
| timer.actionCommand = actionCommand; |
| return timer; |
| } |
| } |