ErrorHandlerTest.java Source code

Introduction

Here is the source code for ErrorHandlerTest.java

Source

/*
 * Copyright (c) Ian F. Darwin, http://www.darwinsys.com/, 1996-2002.
 * All rights reserved. Software written by Ian F. Darwin and others.
 * $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 * Java, the Duke mascot, and all variants of Sun's Java "steaming coffee
 * cup" logo are trademarks of Sun Microsystems. Sun's, and James Gosling's,
 * pioneering role in inventing and promulgating (and standardizing) the Java 
 * language and environment is gratefully acknowledged.
 * 
 * The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
 * inventing predecessor languages C and C++ is also gratefully acknowledged.
 */

import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;

/**
 * Contrived program showing how to catch Exceptions that occur on the event
 * dispatching thread. Define the System property "sun.awt.exception.handler" to
 * name a class with a method
 * 
 * <pre>
 * 
 *  public void handle(Throwable t)
 *  
 * </pre>.
 * <p>
 * That really is all you have to do to catch GUI Exceptions. But it may change
 * at any time (hence the name sun.awt...).
 * 
 * @author Ian Darwin.
 */
public class ErrorHandlerTest extends JFrame {

    /**
     * A fairly banal GUI, just to show interaction.
     */
    ErrorHandlerTest() {
        super("GUI");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        Container cp = getContentPane();
        JButton bx = new JButton("Throw!");
        bx.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent evt) {
                throw new IllegalArgumentException("foo");
            }
        });
        cp.add(bx);
        setBounds(200, 200, 200, 100);
    }

    public static void main(String[] args) {
        // Tell AWT to invoke my Handler.
        System.setProperty("sun.awt.exception.handler", "ErrorHandler");

        // Now create and show the GUI.
        new ErrorHandlerTest().setVisible(true);
    }
}

/**
 * This class is usable by AWT to handle exceptions.
 * System.setProperty("sun.awt.exception.handler", "ErrorHandler"); This usage
 * is documented in the source code up to 1.4Beta for
 * java.awt.EventDispatchThread. This class exists in all standard
 * implementations (try "javap java.awt.EventQueueDispatchThread"), but is not
 * public so there's no javadoc. NOTE: there is a strong admonition that the
 * interface WILL be changed in future.
 * <p>
 * In real life this could be part of your application, and can do almost
 * anything. The error handler itself does not need to import awt, awt.event,
 * swing, or anything else.
 * 
 * @author Ian Darwin
 * @version $Id: ErrorHandler.java,v 1.4 2003/08/24 12:31:03 ian Exp $
 */

class ErrorHandler extends java.lang.Object {

    /**
     * Default constructor must exist (I know it's the default; this is here in
     * case somebody adds any other constructor).
     */
    public ErrorHandler() {
        System.out.println("CONSTRUCTED");
    }

    public void handle(Throwable t) {
        System.err.println("Hey, I caught it!");
        System.err.println(t.toString());
    }
}