java/12 : java.desktop/javax/swing/package-info.java

javax.swing
https://openjdk.java.net/
GPLv2 + Classpath Exception
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 * Copyright (c) 1998, 2017, 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
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 * questions.
 */

Provides a set of "lightweight" (all-Java language) components
that, to the maximum degree possible, work the same on all platforms. For a
programmer's guide to using these components, see
Creating a GUI with JFC/Swing, a trail in
The Java Tutorial. For other resources, see
Related Documentation.
Swing's Threading Policy
In general Swing is not thread safe. All Swing components and related
classes, unless otherwise documented, must be accessed on the event
dispatching thread.
 Typical Swing applications do processing in response to an event generated from a user gesture. For example, clicking on a JButton notifies all ActionListeners added to the JButton. As all events generated from a user gesture are dispatched on the event dispatching thread, most developers are not impacted by the restriction. 
 Where the impact lies, however, is in constructing and showing a Swing application. Calls to an application's main method, or methods in Applet, are not invoked on the event dispatching thread. As such, care must be taken to transfer control to the event dispatching thread when constructing and showing an application or applet. The preferred way to transfer control and begin working with Swing is to use invokeLater. The invokeLater method schedules a Runnable to be processed on the event dispatching thread. The following two examples work equally well for transferring control and starting up a Swing application: 
import javax.swing.SwingUtilities;
public class MyApp implements Runnable {
    public void run() {
        // Invoked on the event dispatching thread.
        // Construct and show GUI.
    }
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new MyApp());
    }
}
Or:import javax.swing.SwingUtilities;
public class MyApp {
    MyApp(String[] args) {
        // Invoked on the event dispatching thread.
        // Do any initialization here.
    }
    public void show() {
        // Show the UI.
    }
    public static void main(final String[] args) {
        // Schedule a job for the event-dispatching thread:
        // creating and showing this application's GUI.
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new MyApp(args).show();
            }
        });
    }
}
 This restriction also applies to models attached to Swing components. For example, if a TableModel is attached to a JTable, the TableModel should only be modified on the event dispatching thread. If you modify the model on a separate thread you run the risk of exceptions and possible display corruption.  Although it is generally safe to make updates to the UI immediately, when executing on the event dispatch thread, there is an exception : if a model listener tries to further change the UI before the UI has been updated to reflect a pending change then the UI may render incorrectly. This can happen if an application installed listener needs to update the UI in response to an event which will cause a change in the model structure. It is important to first allow component installed listeners to process this change, since there is no guarantee of the order in which listeners may be called. The solution is for the application listener to make the change using invokeLater so that any changes to UI rendering will be done post processing all the model listeners installed by the component. 
 As all events are delivered on the event dispatching thread, care must be taken in event processing. In particular, a long running task, such as network io or computational intensive processing, executed on the event dispatching thread blocks the event dispatching thread from dispatching any other events. While the event dispatching thread is blocked the application is completely unresponsive to user input. Refer to SwingWorker for the preferred way to do such processing when working with Swing. 

More information on this topic can be found in the
Swing tutorial,
in particular the section on

Concurrency in Swing.
Related Documentation
For overviews, tutorials, examples, guides, and other documentation,
please see:

    The Swing Connection
    The Java Tutorial
    Online Training
    at the Java Developer Connection ^SM
    Java Foundation Classes (JFC) home page

@serial exclude/**
 * Provides a set of &quot;lightweight&quot; (all-Java language) components
 * that, to the maximum degree possible, work the same on all platforms. For a
 * programmer's guide to using these components, see
 * <a href="https://docs.oracle.com/javase/tutorial/uiswing/index.html"
 * target="_top">Creating a GUI with JFC/Swing</a>, a trail in
 * <em>The Java Tutorial</em>. For other resources, see
 * <a href="#related">Related Documentation</a>.
 *
 * <h2><a id="threading">Swing's Threading Policy</a></h2>
 * In general Swing is not thread safe. All Swing components and related
 * classes, unless otherwise documented, must be accessed on the event
 * dispatching thread.
 * <p>
 * Typical Swing applications do processing in response to an event generated
 * from a user gesture. For example, clicking on a {@code JButton} notifies all
 * {@code ActionListeners} added to the {@code JButton}. As all events generated
 * from a user gesture are dispatched on the event dispatching thread, most
 * developers are not impacted by the restriction.
 * <p>
 * Where the impact lies, however, is in constructing and showing a Swing
 * application. Calls to an application's {@code main} method, or methods in
 * {@code Applet}, are not invoked on the event dispatching thread. As such,
 * care must be taken to transfer control to the event dispatching thread when
 * constructing and showing an application or applet. The preferred way to
 * transfer control and begin working with Swing is to use {@code invokeLater}.
 * The {@code invokeLater} method schedules a {@code Runnable} to be processed
 * on the event dispatching thread. The following two examples work equally well
 * for transferring control and starting up a Swing application:
 * <pre>
 * import javax.swing.SwingUtilities;
 *
 * public class MyApp implements Runnable {
 *     public void run() {
 *         // Invoked on the event dispatching thread.
 *         // Construct and show GUI.
 *     }
 *
 *     public static void main(String[] args) {
 *         SwingUtilities.invokeLater(new MyApp());
 *     }
 * }</pre>
 * Or:<pre>
 * import javax.swing.SwingUtilities;
 *
 * public class MyApp {
 *     MyApp(String[] args) {
 *         // Invoked on the event dispatching thread.
 *         // Do any initialization here.
 *     }
 *
 *     public void show() {
 *         // Show the UI.
 *     }
 *
 *     public static void main(final String[] args) {
 *         // Schedule a job for the event-dispatching thread:
 *         // creating and showing this application's GUI.
 *         SwingUtilities.invokeLater(new Runnable() {
 *             public void run() {
 *                 new MyApp(args).show();
 *             }
 *         });
 *     }
 * }</pre>
 * This restriction also applies to models attached to Swing components. For
 * example, if a {@code TableModel} is attached to a {@code JTable}, the
 * {@code TableModel} should only be modified on the event dispatching thread.
 * If you modify the model on a separate thread you run the risk of exceptions
 * and possible display corruption.
 * <p>
 * Although it is generally safe to make updates to the UI immediately,
 * when executing on the event dispatch thread, there is an exception :
 * if a model listener tries to further change the UI before the UI has been
 * updated to reflect a pending change then the UI may render incorrectly.
 *
 * This can happen if an application installed listener needs to update the UI
 * in response to an event which will cause a change in the model structure.
 * It is important to first allow component installed listeners to process this
 * change, since there is no guarantee of the order in which listeners may be
 * called.
 *
 * The solution is for the application listener to make the change using
 * {@link SwingUtilities.invokeLater} so that any changes to  UI rendering will
 * be done post processing all the model listeners installed by the component.
 * </p>
 * <p>
 *
 * As all events are delivered on the event dispatching thread, care must be
 * taken in event processing. In particular, a long running task, such as
 * network io or computational intensive processing, executed on the event
 * dispatching thread blocks the event dispatching thread from dispatching any
 * other events. While the event dispatching thread is blocked the application
 * is completely unresponsive to user input. Refer to
 * {@link javax.swing.SwingWorker} for the preferred way to do such processing
 * when working with Swing.
 * <p>
 * More information on this topic can be found in the
 * <a href="https://docs.oracle.com/javase/tutorial/uiswing/">Swing tutorial</a>,
 * in particular the section on
 * <a
 * href="https://docs.oracle.com/javase/tutorial/uiswing/concurrency/index.html">
 * Concurrency in Swing</a>.
 *
 * <h2><a id="related">Related Documentation</a></h2>
 * For overviews, tutorials, examples, guides, and other documentation,
 * please see:
 * <ul>
 *     <li><a href="http://www.oracle.com/technetwork/java/javase/tech/articles-jsp-139072.html"
 *     target="_top">The Swing Connection</a></li>
 *     <li><a href="https://docs.oracle.com/javase/tutorial/"
 *     target="_top">The Java Tutorial</a></li>
 *     <li><a href="http://www.oracle.com/technetwork/java/javase/training/index.html"
 *     target="_top">Online Training</a>
 *     at the Java Developer Connection <sup>SM</sup></li>
 *     <li><a href="http://www.oracle.com/technetwork/java/javase/tech/index-jsp-142216.html"
 *     target="_top">Java Foundation Classes (JFC)</a> home page</li>
 * </ul>
 *
 * @serial exclude
 */
package javax.swing;
/

java/ 12/ java.desktop/javax/swing/package-info.java

Swing's Threading Policy

Related Documentation
