Java example source code file (TracedEventQueue.java)

This example Java source code file (TracedEventQueue.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

awt, eventqueue, numberformatexception, string, stringtokenizer, tracedeventqueue, util

The TracedEventQueue.java Java example source code

/*
 * Copyright (c) 1997, 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.
 */

/**
 * An EventQueue subclass which adds selective tracing of events as they
 * are posted to an EventQueue.  Tracing is globally enabled and disabled
 * by the AWT.TraceEventPosting property in awt.properties.  <P>
 *
 * The optional AWT.NoTraceIDs property defines a list of AWTEvent IDs
 * which should not be traced, such as MouseEvent.MOUSE_MOVED or PaintEvents.
 * This list is declared by specifying the decimal value of each event's ID,
 * separated by commas.
 *
 * @author  Thomas Ball
 */

package sun.awt;

import java.awt.EventQueue;
import java.awt.AWTEvent;
import java.awt.Toolkit;
import java.util.StringTokenizer;

public class TracedEventQueue extends EventQueue {

    // Determines whether any event tracing is enabled.
    static boolean trace = false;

    // The list of event IDs to ignore when tracing.
    static int suppressedIDs[] = null;

    static {
        String s = Toolkit.getProperty("AWT.IgnoreEventIDs", "");
        if (s.length() > 0) {
            StringTokenizer st = new StringTokenizer(s, ",");
            int nIDs = st.countTokens();
            suppressedIDs = new int[nIDs];
            for (int i = 0; i < nIDs; i++) {
                String idString = st.nextToken();
                try {
                    suppressedIDs[i] = Integer.parseInt(idString);
                } catch (NumberFormatException e) {
                    System.err.println("Bad ID listed in AWT.IgnoreEventIDs " +
                                       "in awt.properties: \"" +
                                       idString + "\" -- skipped");
                    suppressedIDs[i] = 0;
                }
            }
        } else {
            suppressedIDs = new int[0];
        }
    }

    public void postEvent(AWTEvent theEvent) {
        boolean printEvent = true;
        int id = theEvent.getID();
        for (int i = 0; i < suppressedIDs.length; i++) {
            if (id == suppressedIDs[i]) {
                printEvent = false;
                break;
            }
        }
        if (printEvent) {
            System.out.println(Thread.currentThread().getName() +
                               ": " + theEvent);
        }
        super.postEvent(theEvent);
    }
}