Java tutorial
/* * Copyright (c) 1995, 2009, Oracle and/or its affiliates. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * - 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. * * - Neither the name of Oracle or the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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. */ import javax.swing.*; import java.applet.*; import java.awt.*; import java.awt.event.*; import java.util.Enumeration; public class GetApplets extends JApplet implements ActionListener { private JTextArea textArea; public void init() { //Execute a job on the event-dispatching thread: //creating this applet's GUI. try { javax.swing.SwingUtilities.invokeAndWait(new Runnable() { public void run() { createGUI(); } }); } catch (Exception e) { System.err.println("createGUI didn't successfully complete"); } } private void createGUI() { JPanel contentPane = new JPanel(new BorderLayout()); contentPane.setBorder(BorderFactory.createCompoundBorder(BorderFactory.createLineBorder(Color.BLACK), BorderFactory.createEmptyBorder(10, 10, 10, 10))); setContentPane(contentPane); JButton b = new JButton("Click to call getApplets()"); b.addActionListener(this); add(b, BorderLayout.PAGE_START); textArea = new JTextArea(5, 40); textArea.setEditable(false); JScrollPane scroller = new JScrollPane(textArea); add(scroller, BorderLayout.CENTER); } public void actionPerformed(ActionEvent event) { printApplets(); } public String getAppletInfo() { return "GetApplets"; } public void printApplets() { //Enumeration will contain all applets on this page //(including this one) that we can send messages to. Enumeration e = getAppletContext().getApplets(); textArea.append("Results of getApplets():\n"); while (e.hasMoreElements()) { Applet applet = (Applet) e.nextElement(); String info = ((Applet) applet).getAppletInfo(); if (info != null) { textArea.append("- " + info + "\n"); } else { textArea.append("- " + applet.getClass().getName() + "\n"); } } textArea.append("________________________\n\n"); } }