com.darwinsys.swingui.ErrorUtil Maven / Gradle / Ivy

Go to download
package com.darwinsys.swingui;

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.CharArrayWriter;
import java.io.PrintWriter;
import java.sql.SQLException;

import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JTextArea;

/**
 * Convenience class for fielding Exceptions in a Swing App.
 * Displays exceptions in a JOptionPane, and follows chained
 * exceptions, both the old SQLException.getNextExeption() and
 * the more general Exception.getCause().
 * 
 * The user can press a Details... button to see the stack
 * traceback in a dialog; tracebacks are not displayed unless
 * the user requests them.
 * @author Ian Darwin
 */
public class ErrorUtil {

    // static { System.out.println("ErrorUtil loaded"); }

    /** The button options for the ultimate (or only) Excepton */
    final static String[] choicesNoMore = { "OK", "Details..." };

    /** The button options for any non-ultimate Exception */
    final static String[] choicesMore = { "OK", "Details...", "Next" };

    /** Secondary dialog for the "Details..." button */
    static DetailsDialog detailsDialog;

    /** Public no-arg constructor for those who like simple instantiation. */
    public ErrorUtil() {
        // Nothing to do
    }

    /** Convenience routine for use with AWT's dispatch thread; this is the old,
     * never-supported and now often-doesn't-work method, but the code is still here.
     * Usage:
     * 
     * System.setProperty("sun.awt.exception.handler", "com.darwinsys.swingui.ErrorUtil");
     * 
	 * @param th The Throwable to handle.
     */
    public void handle(Throwable th) {
        //System.out.println("handle() called with " + th.getClass().getName());
        showExceptions(null, th);
    }
        
    // tag::main[]
    /**
	 * Show the given Exception (and any nested Exceptions) in JOptionPane(s).
	 * @param parent The parent window or frame
	 * @param theExc The Exception object
     */
    public static void showExceptions(Component parent, Throwable theExc) {

        Throwable next = null;

        do {
            String className = theExc.getClass().getName();
            String message = className;

            if (theExc instanceof SQLException) {
                SQLException sexc = (SQLException)theExc;
                message += "; code=" + sexc.getErrorCode();
                next = sexc.getNextException();
            } else {
                next = theExc.getCause();   // Comment out if < JDK 1.4
			}

            String[] choices = next != null ? choicesMore : choicesNoMore;

            /* Show the Dialog! */
            int response = JOptionPane.showOptionDialog(
                parent,
                message,
                className,                             // title
                JOptionPane.YES_NO_CANCEL_OPTION,      // icontType
                JOptionPane.ERROR_MESSAGE,             // messageType
                null,                                  // icon
                choices,                               // options
                choices[0]                             // default
                );

            if (response == 0)          // "OK"
                return;
            if (response == 1) {        // "Details"
                // show ANOTHER JDialog with a JTextArea of printStackTrace();
                if (detailsDialog == null) // first time, lazy creation
                    detailsDialog = new DetailsDialog((JFrame)parent);
                detailsDialog.showStackTrace(theExc);
            }
            // else resp = 2, "Next", let it fall through:

            theExc = next;

        } while (next != null);
    }

    /** JDialog class to display the details of an Exception */
    protected static class DetailsDialog extends JDialog {

        private static final long serialVersionUID = -4779441441693785664L;
        JButton ok;
        JTextArea text;
        /** Construct a DetailsDialog given a parent (Frame/JFrame) */
        DetailsDialog(JFrame parent) {
            super(parent);
            Container cp = getContentPane();
            text = new JTextArea(40, 40);
            cp.add(text, BorderLayout.CENTER);
            ok = new JButton("Close");
            cp.add(ok, BorderLayout.SOUTH);
            ok.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent evt) {
                    dispose();
                }
            });
            pack();
        }

        /** Display the stackTrace from the given Throwable in this Dialog. */
        void showStackTrace(Throwable exc) {
            CharArrayWriter buff = new CharArrayWriter();
            PrintWriter pw = new PrintWriter(buff);
            exc.printStackTrace(pw);
            pw.close();
            text.setText(buff.toString());
            setVisible(true);
        }
    }
    // end::main[]
}