Mini Appletviewer : Applet « Development « Java Tutorial

1. Java Tutorial
2. Development
3. Applet

import java.applet.Applet;
import java.applet.AppletContext;
import java.applet.AppletStub;
import java.applet.AudioClip;
import java.awt.BorderLayout;
import java.awt.Image;
import java.awt.Toolkit;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.Enumeration;
import java.util.Iterator;

import javax.swing.JFrame;

public class MinAppletviewer {
  public static void main(String args[]) throws Exception {
    AppSupport theAppSupport = new AppSupport();
    JFrame f = new JFrame();
    URL toload = new URL(args[0]);
    String host = toload.getHost();
    int port = toload.getPort();
    String protocol = toload.getProtocol();
    String path = toload.getFile();
    int join = path.lastIndexOf('/');
    String file = path.substring(join + 1);
    path = path.substring(0, join + 1);

    theAppSupport.setCodeBase(new URL(protocol, host, port, path));
    theAppSupport.setDocumentBase(theAppSupport.getCodeBase());

    URL[] bases = { theAppSupport.getCodeBase() };
    URLClassLoader loader = new URLClassLoader(bases);
    Class theAppletClass = loader.loadClass(file);
    Applet theApplet = (Applet) (theAppletClass.newInstance());

    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    f.add(theApplet, BorderLayout.CENTER);

    theApplet.setStub(theAppSupport);

    f.setSize(200, 200);
    f.setVisible(true);
    theApplet.init();
    theApplet.start();
  }
}

class AppSupport implements AppletStub, AppletContext {
  private URL codeBase;

  private URL documentBase;

  public AppSupport() throws Exception {
    URL url = null;
    String urlpart = System.getProperty("user.dir");
    urlpart = urlpart.replace(File.separatorChar, '/');
    url = new URL("file://" + urlpart + "/");
    codeBase = documentBase = url;
  }

  public void appletResize(int w, int h) {
  }

  public AppletContext getAppletContext() {
    return (AppletContext) this;
  }

  public URL getDocumentBase() {
    return documentBase;
  }

  public void setDocumentBase(URL url) {
    documentBase = url;
  }

  public URL getCodeBase() {
    return codeBase;
  }

  public void setCodeBase(URL url) {
    codeBase = url;
  }

  public String getParameter(String s) {
    return null;
  }

  public boolean isActive() {
    return true;
  }

  public Applet getApplet(String name) {
    return null;
  }

  public Enumeration getApplets() {
    return new Enumeration() {
      public boolean hasMoreElements() {
        return false;
      }

      public Object nextElement() {
        return null;
      }
    };
  }

  public AudioClip getAudioClip(URL url) {
    return Applet.newAudioClip(url);
  }

  public Image getImage(URL url) {
    return Toolkit.getDefaultToolkit().getImage(url);
  }

  public void showDocument(URL url) {
  }

  public void showDocument(URL url, String target) {
  }

  public void showStatus(String status) {
    System.err.println(status);
  }

  public void setStream(String key, InputStream stream) throws IOException {
  }

  public InputStream getStream(String key) {
    return null;
  }

  public Iterator<String> getStreamKeys() {
    return null;
  }
}