AppletViewer - a simple Applet Viewer program
/*
* 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.applet.Applet;
import java.applet.AppletContext;
import java.applet.AppletStub;
import java.applet.AudioClip;
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Image;
import java.awt.Label;
import java.awt.Panel;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import javax.swing.JFrame;
/*
* AppletViewer - a simple Applet Viewer program.
* @author Ian Darwin, http://www.darwinsys.com/
*/
public class AppletViewer {
/** The main Frame of this program */
JFrame f;
/** The AppletAdapter (gives AppletStub, AppletContext, showStatus) */
static AppletAdapter aa = null;
/** The name of the Applet subclass */
String appName = null;
/** The Class for the actual applet type */
Class ac = null;
/** The Applet instance we are running, or null. Can not be a JApplet
* until all the entire world is converted to JApplet. */
Applet ai = null;
/** The width of the Applet */
final int WIDTH = 250;
/** The height of the Applet */
final int HEIGHT = 200;
/** Main is where it all starts.
* Construct the GUI. Load the Applet. Start it running.
*/
public static void main(String[] av) {
new AppletViewer(av.length==0?"HelloApplet":av[0]);
}
/** Construct the GUI for an Applet Viewer */
AppletViewer(String appName) {
super();
this.appName = appName;
f = new JFrame("AppletViewer");
f.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
f.setVisible(false);
f.dispose();
System.exit(0);
}
});
Container cp = f.getContentPane();
cp.setLayout(new BorderLayout());
// Instantiate the AppletAdapter which gives us
// AppletStub and AppletContext.
if (aa == null)
aa = new AppletAdapter();
// The AppletAdapter also gives us showStatus.
// Therefore, must add() it very early on, since the Applet's
// Constructor or its init() may use showStatus()
cp.add(BorderLayout.SOUTH, aa);
showStatus("Loading Applet " + appName);
loadApplet(appName , WIDTH, HEIGHT); // sets ac and ai
if (ai == null)
return;
// Now right away, tell the Applet how to find showStatus et al.
ai.setStub(aa);
// Connect the Applet to the Frame.
cp.add(BorderLayout.CENTER, ai);
Dimension d = ai.getSize();
d.height += aa.getSize().height;
f.setSize(d);
f.setVisible(true); // make the Frame and all in it appear
showStatus("Applet " + appName + " loaded");
// Here we pretend to be a browser!
ai.init();
ai.start();
}
/*
* Load the Applet into memory. Should do caching.
*/
void loadApplet(String appletName, int w, int h) {
// appletName = ... extract from the HTML CODE= somehow ...;
// width = ditto
// height = ditto
try {
// get a Class object for the Applet subclass
ac = Class.forName(appletName);
// Construct an instance (as if using no-argument constructor)
ai = (Applet) ac.newInstance();
} catch(ClassNotFoundException e) {
showStatus("Applet subclass " + appletName + " did not load");
return;
} catch (Exception e ){
showStatus("Applet " + appletName + " did not instantiate");
return;
}
ai.setSize(w, h);
}
public void showStatus(String s) {
aa.getAppletContext().showStatus(s);
}
}
/*
* AppletAdaptor: partial implementation of AppletStub and AppletContext.
*
* This code is far from finished, as you will see.
*
* @author Ian Darwin, http://www.darwinsys.com/, for Learning Tree Course 478
*/
class AppletAdapter extends Panel implements AppletStub, AppletContext {
/** The status window at the bottom */
Label status = null;
/** Construct the GUI for an Applet Status window */
AppletAdapter() {
super();
// Must do this very early on, since the Applet's
// Constructor or its init() may use showStatus()
add(status = new Label());
// Give "status" the full width
status.setSize(getSize().width, status.getSize().height);
showStatus("AppletAdapter constructed"); // now it can be said
}
/****************** AppletStub ***********************/
/** Called when the applet wants to be resized. */
public void appletResize(int w, int h) {
// applet.setSize(w, h);
}
/** Gets a reference to the applet's context. */
public AppletContext getAppletContext() {
return this;
}
/** Gets the base URL. */
public URL getCodeBase() {
return getClass().getResource(".");
}
/** Gets the document URL. */
public URL getDocumentBase() {
return getClass().getResource(".");
}
/** Returns the value of the named parameter in the HTML tag. */
public String getParameter(String name) {
String value = null;
return value;
}
/** Determines if the applet is active. */
public boolean isActive() {
return true;
}
/************************ AppletContext ************************/
/** Finds and returns the applet with the given name. */
public Applet getApplet(String an) {
return null;
}
/** Finds all the applets in the document */
public Enumeration getApplets() {
class AppletLister implements Enumeration {
public boolean hasMoreElements() {
return false;
}
public Object nextElement() {
return null;
}
}
return new AppletLister();
}
/** Create an audio clip for the given URL of a .au file */
public AudioClip getAudioClip(URL u) {
return null;
}
/** Look up and create an Image object that can be paint()ed */
public Image getImage(URL u) {
return null;
}
/** Request to overlay the current page with a new one - ignored */
public void showDocument(URL u) {
}
/** as above but with a Frame target */
public void showDocument(URL u, String frame) {
}
/** Called by the Applet to display a message in the bottom line */
public void showStatus(String msg) {
if (msg == null)
msg = "";
status.setText(msg);
}
/* StreamKey stuff - new in JDK1.4 */
Map streamMap = new HashMap();
/** Associate the stream with the key. */
public void setStream(String key, InputStream stream) throws IOException {
streamMap.put(key, stream);
}
public InputStream getStream(String key) {
return (InputStream)streamMap.get(key);
}
public Iterator getStreamKeys() {
return streamMap.keySet().iterator();
}
}
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